cal Sound A1 aska F. D.

UNITED STATES DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT S E R V I C E

Geol og i cal and Opera t iona l Summary Nor ton Sound COST No. 2 Well

Nor ton Sound, A1 aska

R. F. Turner ( e d ) , J. G. Bolrn, C. M. McCarthy, D. A. S t e f f y , Paul Lowry, T. 0. F l e t t , and Dav id B l u n t

U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 83-557

Th is r e p o r t has n o t been e d i t e d f o r conformity w i t h M ine ra l s Management Se rv i ce and U.S. Geo log ica l Survey e d i t o r i a l s tandards o r s t r a t i g r a p h i c nomenclature,

Any tise o f t r a d e names i s f o r d e s c r i p t i v e purposes o n l y and does n o t c o n s t i t u t e endorsement o f these p roduc ts by t h e M ine ra l s Management Se rv i ce and Geo lo$ ica l Survey.

CONTENTS

I n t r o d u c t i o n

Opera t iona l Summary

Sha l l ow Geol o g i c S e t t i ng

Seismic K e f l e c t i o n C o r r e l a t i o n and V e l o c i t y A n a l y s i s

Pa leon to l ogy and B i o s t r a t i graphy

Geophysical Log I n t e r p r e t a t i o n

Geochemi s t ry

Env i ronmental Cons idera t ions

Summary and Conc 1 us i ons

References

ILLUSTRATIONS

F i g u r e 1. L o c a t i o n map

2. F i n a l l o c a t i o n p l o t

3. Graph showing d a i l y d r i l l i n g p rogress

4. Schematic d iagram showing cas ing , s t r i n g s , p l ugging, and abandonment program

5. Changes w i t h depth o f d r i l l i n g p r o p e r t i e s .

6. L o c a t i o n diagram showing Nor ton Bas in , COST we1 1 s 1 and 2, and USGS se ismic 1 i nes

7. S y n t h e t i c Seismogram

8. USGS se ismic l i n e 807

9. USGS se ismic l i n e 81 3

10. USGS se ismic l i n e 802

11, T i m e - s t r a t i g r a p h i c column and se ismic p r o f i l e

Page

1

5

17

21

3 9

5 8

99

121

132

144

Page - 12. Compari son between s t a c k i n g ve l o c i t i es and RMS

ve l o c i t i e s

13. I n t e r v a l v e l o c i t i e s and t ime-depth cu rve f rom son ic 1 og o f COST we1 1 2

14. I n t e r v a l v e l o c i t i e s and t ime-depth curves f rorn s e i srnic da ta near COST we1 1 2

15. Comparison between t ime-depth curves d e r i v e d froin se ismic and son i c da ta f o r COST w e l l 2

16, Cornparison between t ime-depth curves f o r COST w e l l s 1 and 2

17. B i o s t r a t i g raph ic c o r r e l a t i ons o f Nor ton Sound COST we1 1 s

18. S t r a t i g r a p h i c summary o f Nor ton Sound COST No. 1 w e l l

19. S t r a t i g r a p h i c summary of Nor ton Sound COST No. 2 well

20. Ternary d i agrams o f framework c l a s t coniposi t i on o f sandstone

21. D e s c r i p t i o n o f conven t iona l c o r e 1


23. D e s c r i p t i o n o f conven t iona l co re 3



26. D e s c r i p t i o n of conven t iona l c o r e 6


28. D e s c r i p t i o n of conven t iona l c o r e 8




32: D e s c r i p t i o n o f conven t iona l co re 12

ILLUSTRATIONS (cont . )

33 , D e s c r i p t i o n o f conven t iona l c o r e 13

34. Decrease i n p o r o s i t y w i t h dep th

35. Re1 a t i o n s h i p between p o r o s i t y and permeabi 1 i t y o f sandstones

36. Temperature l o g da ta

37. Organic r i chness Cis+ e x t r a c t a b l e o rgan i c m a t t e r

38. C l a s s i f i c a t i o n o f o rgan i c ma t te r

39. Van Krevel en diagram. E l emental analyses

40. Selected i n d i c a t o r s o f thermal ma tu ra t i on

41. Represen ta t i ve Cis+ gas chromatograms

42. Organic r i chness and hydrocarbon p o t e n t i a l

PLATES

P l a t e 1. S t r a t i g r a p h i c co lu~nn and summary c h a r t o f geo log ic d a t a , COST No. 1 We1 1, Nor ton Sound, Alaska.

TABLES

T a b l e 1. P o r o s i t y and p e r m e a b i l i t y , Nor ton 2

Page - 88

96

iii

Geol og i c and Opera t iona l Summary

Nor ton Sound COST No. 2 Well

B e r i n g Sea Area, A1 aska

Ronald F. Turner , E d i t o r

I NTROOUCTION

T i t l e 30, Code o f Federa l Regu la t i ons (CFR) , paragraph 251.1 4 s t i p u l a t e s

t h a t g e o l o g i c a l d a t a and processed geo log i ca l i n f o r m a t i o n ob ta i ned f rorn Deep

S t r a t i g r a p h i c Test w e l l s d r i l l e d on t h e Outer Con t i nen ta l S h e l f ( O C S ) be made

a v a i l a b l e f o r p u b l i c i n s p e c t i o n 60 ca lenda r days a f t e r t h e issuance o f t h e f i r s t

Federal l e a s e w i t h i n 50 n a u t i c a l m i l e s o f t h e w e l l s i t e o r 10 years a f t e r comp le t i on

o f t h e w e l l i f no leases a re issued. T r a c t s w i t h i n t h i s d i s t a n c e o f t h e f i r s t

Nor ton Sound Deep S t r a t i g r a p h i c Tes t we1 1 (des igna ted t h e ARC0 Nor ton Sound

COST No. 2 Well by t h e o p e r a t o r and h e r e a f t e r r e f e r r e d t o as t h e w e l l o r t h e

No. 2 w e l l ) were o f f e r e d f o r l e a s e i n Sa le 57 on March 15, 1983. N i n e t y - e i g h t

b i d s on 6 4 t r a c t s were r ece i ved w i t h t h e t o t a l h i g h b i d s amounting t o $325

m i l l i o n . F i f t y - n i n e b i d s were accepted and f i v e r e j e c t e d . The e f f e c t i v e

i ssuance d a t e o f t h e leases i s June 1, 1983.

Th i s o p e n - f i l e r e p o r t i s p resen ted i n accordance w i t h t h e requi rements o f

30 CFR 251.14. The i n t e r p r e t a t i o n s con ta i ned h e r e i n a r e c h i e f l y t h e work o f

M i n e r a l s Management S e r v i c e personnel , a1 though s u b s t a n t i a l c o n t r i b u t i o n s were

a made by geosc ience c o n s u l t i n g companies.

The ARC0 Nor ton Sound No. 2 w e l l was completed on August 27, 1982, on

OCS Lease B lock 273, l o c a t e d approx imate ly 68 m i l e s sou th o f Nome, Alaska

( f i g . 1 ) The we1 1 da ta i s a v a i l a b l e f o r p u b l i c i n s p e c t i o n a t t h e M i n e r a l s

Management Serv ice , O f f sho re F i e l d Operat ions o f f i c e , l o c a t e d a t 800 "A" S t r e e t ,

Anchorage, A1 aska , 99501 .

A l l measurements a r e g i ven as measured depths i n f e e t from t h e K e l l y

Bushing ( K B ) , which was 105 f e e t above sea level . For t h e most p a r t , measurements

a r e g i v e n i n U.S. Customary U n i t s except where s c i e n t i f i c conven t ion d i c t a t e s

m e t r i c usage. A conve rs i on c h a r t i s prov ided.

EQUIVALENT MEASUREMENT UNITS

U.S. Customary t o S I M e t r i c U n i t s :

1 i n c h = 2.54 cen t ime te r s

1 f o o t = 0.3048 meter

1 s t a t u t e m i l e = 1.61 k i l o m e t e r s

1 n a u t i c a l m i l e = 1.85 k i l o m e t e r s

1 pound = 0.45 k i l o g r a m

1 pound/gal l o n = 1 1 9.83 k i 1 ograms/cubic meter

1 pound/square i n c h = 0.07 k i 1 ograms/square cen t i rneters

1 g a l l o n = 3.78 l i t e r s ( c u b i c dec imete rs )

1 b a r r e l = ( 4 2 U.S. g a l s . ) = 0.16 c u b i c meters

Temperature i n degrees Fahrenhe i t = O F l e s s 32, d i v i d e d by 1.8 f o r degrees

Ce l s i us .

O ther Conversions: 1 k n o t = 1 n a u t i c a l m i l @/hour

1 n a u t i c a l m i l e = 1.15 s t a t u t e m i l e s o r 6,080 f e e t

OPERATIONAL SUMMARY

by

Col 1 een McCarthy

The jackup d r i l l i n g r i g , Key Singapore, a r r i v e d on l o c a t i o n i n Nor ton Sound

on June 3, 1982, 1630 hours A.S.T. and t h e Nor ton Sound Con t i nen ta l Of fshore

S t r a t i g r a p h i c Tes t No. 2 w e l l was spudded June 7, 1982. D r i l l i n g was completed

81 days l a t e r on August 27, 1982 a t a t r u e v e r t i c a l depth o f 14,889 f e e t .

A f t e r w i r e l i n e l ogg ing , runn ing v e l o c i t y and temperature surveys, s i dewa l l

co r i ng , and d r i l l - s t e m t e s t i n g were accomplished, t h e w e l l was plugged and

abandoned, and t h e r i g was under tow by September 20, 1982.

The c o n s t r u c t i o n o f t h e Key Singapore, owned by K e y d r i l Company, was

completed i n March o f 1982 and t h e r i g was g iven t h e c l a s s i f i c a t i o n ABS l - A .

M ine ra l s Management Se rv i ce r e p r e s e n t a t i v e s inspec ted t h e r i g March 15, 1982.

The Key Singapore i s a Le Tourneau 116-C des ign and i s a s e l f - e l e v a t i n g

d r i l l i n g u n i t . It was designed t o w i t hs tand 35- foo t waves and 115-knot winds

i n 300 f e e t o f water. The r i g was r a t e d a t an a i r temperature o f -10" and f o r

a d r i l l i n g depth o f 30,000 f e e t i n 300 f e e t water depth. The Key Singapore

was p r o p e r l y w i n t e r i z e d f o r a r c t i c use, and t h e r e were no ma jo r acc iden t s o r

i n c i d e n t s d u r i n g t h e d r i l l i n g o f t h e w e l l . Whi le t h e r i g was be ing towed o u t

o f Alaskan waters, however, i t c o l l i d e d w i t h rocks o f f t h e A l e u t i a n Chain and

a1 1 personnel were evacuated. The Key Singapore was recovered w i t h no major

damage t o t h e r i g .

A s t udy was made by Woodward-Clyde Consu l t an t s t o o b t a i n i n f o r m a t i o n on

t h e subsur face c o n d i t i o n s a t t h e d r i l l i n g l o c a t i o n i n o r d e r t o develop c r i t e r i a

and recommendations f o r jackup r i g s i t i n g , des ign, and i n s t a l l a t i o n o f t h e

p l a t f o r m p i l e s and conductors. Th is was accompl ished by d r i l l i n g t h r e e bo r i ngs ;

one 300- foo t p e n e t r a t i o n and two 50- foo t pene t ra t i ons . The samples recovered

were t hen t e s t e d , b o t h on board t h e research vessel and i n t h e l a b o r a t o r y , t o

de te rmine t h e des ign s t r e n g t h p r o p e r t i e s o f t h e f ounda t i on s o i l s .

Nome, which i s app rox ima te l y 68 m i l e s NW o f t h e l o c a t i o n , was t h e shore

base f o r sea and a i r suppor t opera t ions . Kenai and Dutch Harbor Here occds iona l

sources o f n o n r o u t i n e equipment and i n a t e r i a l s supply. A1 1 major m a t e r i a l s

needed f o r t h e e n t i r e w e l l were s t o r e d on a l a r g e supp ly barge anchored

approx imate ly one m i l e f r om t h e d r i l l i n g l o c a t i o n . Two sea-go ing supp ly boa ts

s h u t t l e d m a t e r i a l between t h e barge and t h e r i g . These supp ly boa ts a l s o

suppl i ed f u e l , water , and m i s ce l 1 aneous cargo v i a 1 i ghterage barge f r o ~ n t4one.

He1 i c o p t e r s c e r t i f i e d f o r i ns t r umen t f l i g h t t r a n s p o r t e d personnel , g roce r i es ,

and l i g h t w e i g h t equipment between t h e r i g and t h e p r ima ry shore base a t Nome.

Personnel , equipment, and suppl i e d were t r a n s p o r t e d t o and f rorn t h e shore base

by b o t h c h a r t e r e d and commercial a i r c a r r i e r s .

ARC0 Alaska ac ted as t h e o p e r a t o r f o r i t s e l f and t h e f o l l o w i n g n ine teen

companies t h a t shared expenses f o r t h e w e l l .

AMOCO Product i o n Co.

Chevron, U.S.A., I nc ,

C i t i e s S e r v i c e Co.

CONOCO, I nc .

E l f - A q u i t a n e Co.

Exxon Company, U.S.A.

Ge t t y O i l Co.

G u l f O i l Corp.

Marathon O i l Co.

Mobil E x p l o r a t i o n and P roduc t i on Se rv i ce

Murphy O i l Corp.

Pennzoi l Oil and Gas, Inc .

Phi 11 i p s P e t r o l eum Co.

She1 1 O i l Co.

Sohi o A1 aska Petro leum Co.

Sun O i l Co.

Tenneco O i 1 Co,

Texaco, Inc .

Union O i l Company o f C a l i f o r n i a

Nor ton Sound COST No. 2 we1 1 was 1 ocated a t 1 a t 63" 41 ' 49.43" N; 1 ong 164" 1 1 '

03.38" W, o r UTM c o o r d i n a t e s (zone 3 ) X = 540,331.3 rn and Y = 7,063,318.2 m.

The survey p l a t f o r t h e f i n a l w e l l s i t e l o c a t i o n i s shown i n F i g u r e 2. Water

depth a t t h e l o c a t i o n i s 49 f e e t . A l l measurements were made frorn t h e K e l l y

Bushing (KB) which was 105 f e e t above sea l e v e l and 154 f e e t above t h e s e a f l o o r .

BLOCK 273

WELL LOCATION

2869 METERS - - - - - - - - - - - _ - 7 I

I I

2 I I- :'

PP l G I N

1 I 0 1,000

I u Meters

I

GEODETIC POSITION UNIVERSAL TRANSVERSE MERCATOR COORDINATES, ZONE 3, in METERS.

L AT. 63O 4 1 ' 4 9 . 4 3 " ~ . y = 7,063,318.2 LONG. 164O 1 1' 03.38" W. x = 540,331.3

Figure 2. Final location plat showing the posit ion o f Norton Sound COST No. 2 well in O C S P r o t r a c t ion Diagram "s t . Michoel, NP 3-2.''

The w e l l was d r i l l e d t o a dep th of 10,254 f e e t w i t h l e s s than 4" d e v i a t i o n f rom

v e r t i c a l ; t h e ang le i nc reased t o 6' by 12,020 f e e t ; and a t t o t a l t r u e v e r t i c a l

depth, 14,889 f e e t , d e v i a t i o n was 10'.

D r i l l i n g s t i p u l a t i o n s r e q u i r e d t h e o p e r a t o r t o p r o v i d e t h e M i n e r a l s

Management S e r v i c e w i t h a1 1 we1 1 l ogs , samples, c o r e s l a b s , o p e r a t i o n a l and

t e c h n i c a l r e p o r t s , and geo log i c i n f o rma t i on .

Owing t o t h e i c e season i n Nor ton Sound t h e d r i l l i n g window i s f rom June

t o October.

D r i l l i n g Program

@ The No. 2 we1 1 was d r i l l e d u s i n g s i x t e e n 12 1 /4 - i nch d r i l l b i t s t o a dep th

o f 11,555 f e e t and deepened w i t h f o u r t e e n 3 1 /2 - i nch b i t s t o 14,889 f e e t .

A d d i t i o n a l b i t s were used t o open t h e h o l e be fo re s e t t i n g t h e l a r g e r cas i ng

s t r i n g s , t o d r i l l t h rough cement, f o r c lean-ou t t r i p s , and f o r t h e conven t i ona l

c o r i n g program. D r i l l i n g r a t e s ranged f rom 3 t o 250 f e e t / h o u r , and averaged

100 f e e t / h o u r down t o 3900 f ee t , 75 f e e t / h o u r t o 7400 f e e t , 35 f e e t / h o u r t o

11,400 f e e t , and 14 fee t /hour f o r t h e remainder o f t h e w e l l . The d a i l y d r i l l i n g

p rogress f o r t he w e l l i s shown on F i g u r e 3.

Four s t r i n g s o f cas i ng were cemented i n t h e w e l l , a s shown in F i g u r e 4.

The 30-inch conduc to r c a s i n g was s e t a t 476 feet , w i t h 950 sacks o f Class G

cement. A t 1181 f e e t , 2200 sacks o f C lass G cement were used t o cement t h e 20-

Day o f Month

0 10 20 30 10 20 3 1 10 20 3 1 10 20

Figure 3. Graph showing daily drilling progress f o r N o r t o n Sound COST No. 2 well, 1982.

I 1 1 I I

casing I

- ?, 20" I cas ing

-

I I

-

I I I

1 I

-

-

-

-

JUNE

I I

I

\ -

\

-9s/a'' casing

T.D. 14,889' 4

I JULY I AUGUST SEPTEMBER i

Oepth below K 0 Sea Floor ot 154'

30" Cut at 175'

20" Cut at 350 '

133/1'' Cut at 36 9'

9YaL' Cut at 380'

- 3 0 " Casing a t 416' Sur f p c r Plug 200 - 460 '

Plug 13Yat' x 9 - 20"Casing o t 1181'

Annulus 4,181'-9,671' Perf orations at 4~71 ' -4 ,373 ' Rmfainrr a t 4,321 v , " g y x - 13~/8" Casing at 4 6 7 3 '

- 3 0 " Casing a t 416' Sur f p c r Plug 200 - 460 '

- 20"Casing o t 1181'

, 133/a" Casing at 4 6 7 3 '

Plug 7,948'- 8,264' Retainer ot 8,086' Per forat ions 8,116'-8,124'

Plug 10,675'- 11,225' Retoiner at 10,859' pe r fo ra t ions 10,901'- 10,909'

Plug 11,651'- 12,000' Retainer a t 11,810'

Plug 12 ,600~ - 12,900'

I mud I

- 9 '/it Cosing ot 11,862'

mud

Figure 4. Schematic d iagram showing casing strings, plugging, and abandonment program, Nor ton Sound COST No. 2 wet I.

a i n c h cas ing, Whil e cement ing t h e 20- inch cas ing , 1 o s t c i r c u l a t i o n problems

were encountered and t h e r e were no r e t u r n s t o t h e sur face. Twenty- four hundred

sacks o f C lass G cement were used t o cement t h e 13 318- inch cas ing , a t 4673

f e e t . The 9 518- inch c a s i n g was s e t a t 11,862 f e e t w i t h 255 sacks o f Class G

cement and be low t h i s cas i ng p o i n t t h e w e l l was open ho le .

D r i l l i n g Mud

Se lec ted d r i l l i n g mud p r o p e r t i e s and t h e i r changes w i t h dep th a r e shown i n

F i g u r e 5. D r i 11 i n g f l u i d f o r t h e we1 1 was sea water t o 1,231 f ee t , and

1 i g n o s u l f a n a t e mud f o r t h e remainder o f t h e hole. Mud we igh t was kep t a t about

9.0 pounds /ga l lon t o 5100 f e e t , 10 pounds/ga l lon a t 11,100 f e e t and i n c r e a s i n g

t o 12 pounds/gal l o n a t t o t a l depth. V i s c o s i t y v a r i e d between 35 t o 46 seconds

th roughou t t h e w e l l , averag ing around 38 seconds. C h l o r i d e c o n c e n t r a t i o n s

ranged f rom 600 pp~n t o 5700 ppm, general l y dec reas ing w i t h depth. Calc ium

c o n c e n t r a t i o n s Mere g e n e r a l l y l i r n i t e d t o c o n c e n t r a t i o n s near zero, a l t hough

va lues were as h i g h as 500 ppm a t 14,750 fee t . Mud pH ranged f rom 8.0 t o

12.0, s t a y i n g a t about 10.0 th roughou t most o f t h e w e l l . Between 12,212 and

13,717 f e e t , gas assoc ia ted w i t h coa l beds was encountered. Mud we igh t was

i nc reased f rom 10.0 ppg t o 11.5 ppg th roughou t t h i s i n t e r v a l and we1 1 c o n t r o l

was ma in ta i ned a t a l l t imes. Mud-logging s e r v i c e s were p rov i ded by E x p l o r a t i o n

Logging from 154 f e e t t o t o t a l depth,

Figure 5. Changes wi th depth of drilling mud properties. Nor ton Sound COST No. 2 well, including mud weight, viscosity, t o t a l chlorides, and pH.

MUD WEIGHT

( I b s /ga l ) RS 9.0 9.5 10.0 10.5 11.0 l l l

- - - - - - - - - I I , . I I 3% coring 4,673'

- - Q-- w

\ /

I i 1

I

I 1 I 1 !

1 I 1 1 I - I I 1 1

MUD CHLORIDES CALCIUM V I S C O S I T Y

(seconds) ( X 1000 p p m ) ( P P ~ ) 15 40 4 5 1 2 1 4 5 100 200 JW 4 0 0 I 1 I I 1

- 14

I

- -

1 I

- -

MUD pH I # 10 1 1

- -

I I

81' - -

I -

- -

b

Samples and Tests

Dri 11 c u t t i n g s f o r 1 i t h o l o g i c and p a l e o n t o l o g i c analyses were c o l l ected

froin 436 f e e t t o t o t a l depth. T h i r t e e n convent iona l cores were c u t and analyzed

f o r p o r o s i t y , permeabi 1 i t y , and g r a i n dens i ty . The f o l l owing a r e t h e r e s u l t s :

Core No. I n t e r v a l ( f t ) Recovered

Dur i ng s i x runs, s i d e w a l l co res were c o l l e c t e d w i t h t h e f o l l o w i n g r e s u l t s :

Depth Number Number Percent

Run No. _(ft) A t t empt ed Recovered Recovered

TOTAL 777 499 64

Logging runs were made a t depths o f 4700, 11,907, and 14,889 f e e t . The Dual

I n d u c t i on-Later1 og (OIL ) , Borehol e Cornpensated Sonic Log (BHC) , and Spontaneous

P o t e n t i a l (SP), Gamma Ray ( G R ) , Long Spaced Sonic Log (LSS) w i t h I n t e g r a t e d

. Trave l Time ( ITT ) , Repeat Format ion Tes t (RFT), and t h e Four-arm, H igh Reso lu t i on

Cont inuous Dipmeter (HRD) , were recorded on a1 1 runs. The Compensated Neutron

Log (CNL) w i t h Neutron Gamma Tool (NGT) were recorded on t h e f i r s t and second

runs. On t h e second and t h i r d runs a V e r t i c a l Se ismic P r o f i l e ( V S P ) , L i t h o d e n s i t y

Neut r u n Log and Proxirni t y Log-Mi c r o l og (MPL) were recorded. A d d i t i o n a l 1 ogs

run were a Compensated Format ion D e n s i t y (FDC) and a V e l o c i t y Survey on t h e

f i r s t run, and a Cement Bond Log (CBL) and Temperature Log on t h e l a s t run. A

Gamma Ray Casing C o l l a r L o c a t o r was run a t 11,651 f e e t ,

Two d r i l l s tem t e s t s f o r w a t e r ana lys i s were made through p e r f o r a t i o n s i n

the 9 518-inch casing. To min imize r i s k , t e s t i n g was conducted through the

3 1 1 2 - i nch t u b i n g r a t h e r than d r i l l pipe. The f i r s t t e s t was made between

10,901 and 10,909 f e e t and the second between 81 16 and 81 24 f ee t ,

The cumula t i ve cost f o r t h e well was $32.2 m i l l i o n ,

SHALLOW GEOLOGIC SETTING

NORTON SOUND COST NO. 2 WELL

By Dav id S t e f f y

Sha l low g e o l o g i c c h a r a c t e r i s t i c s o f t h e d r i l l s i t e were i d e n t i f i e d i n a

su rvey conducted by Nekton, Inc., i n 1980. The survey, p a r t o f t h e pe rm i t

t o d r i l l a p p l i c a t i o n , i n c l u d e d a geo techn ica l s tudy o f t h e upper 300 f e e t o f

sediment and a h i g h - r e s o l u t i o n s e i s m i c - r e f l e c t i o n survey o f t h e s e a f l o o r and

i t s nea r - su r f ace f ea tu res . The r e g i o n a l d e s c r i p t i o n o f Nor ton Sound i s based

on f i v e U.S. Geo log ica l Survey maps prepared as p a r t o f t h e p re l ease i n v e s t i g a -

t i o n o f t h e su r face and near-sur face geo log i c environment o f Nor ton Sound

@ (Hoose, S te f f y , and Lybeck, 1981 ; S t e f f y and Hoose, 1981 ; S t e f f y and Lybeck,

1981 ; S t e f f y , Turner , and Lybeck, 1981 ; S t e f f y , Turner , Lybeck, and Roe, 1981 ).

Bathymetry

Nor ton Sound i s a f l a t - b o t t o m e d embayment o f t h e n o r t h e a s t e r n B e r i n g Sea

e p i c o n t i n e n t a l she l f . Water depths i n t h e OCS Sa le 5 7 a r e a rarige from 16 t o 89

f e e t . The s a l e area covers p a r t of t h e Yukon R i v e r d e l t a f r o n t and p r o d e l t a ,

which a r e separated from t h e p rog rad ing s h o r e l i n e by a sub ice p l a t f o r m (Larsen,

Nelson, and Thor, 1980). Th i s p l a t f o r m i s 3 t o 1 2 m i l e s wide a l ong the sou thern

boundary o f t h e sale area and occurs i n ~ a t e r depths o f l e s s than 32 f e e t , The

a No. 2 w e l l i s l o c a t e d a t t h e base o f t h e nor thward s l o p i n g Yukon d e l t a f r o n t i n

49 f e e t o f water. The d e l t a f r o n t i s t h e seaward ex tens ion o f Holocene, nearshore

sand d e p o s i t s and i s c h a r a c t e r i z e d by a 1- t o 2-degree seaward s l o p i n g sea f l oo r .

Seaward, t h e f r o n t becomes t h e p r o d e l t a , a ve ry g e n t l y s l o p i n g area t h a t marks

t h e edge o f d e l t a i c sed imentat ion. I n t h e s a l e area t h e p r o d e l t a s lopes l e s s

t h a n 1 degree and i s 52 t o 89 f e e t deep.

Sea- f l o o r Geol ogy

The s e a - f l o o r topography o f t h e Nor ton Sound area i s t h e r e s u l t o f t h e

i n t e r a c t i o n s o f wind, water, i c e , and sed imen ta t i on processes. Sur face sediments

range i n s i z e f r om f i n e sand a t t h e d e l t a f r o n t t o sandy s i l t and s i l t i n t h e

@ p r o d e l t a area. These unconso l ida ted sediments a r e c o n t i n u a l l y reworked by

i c e gouging, c u r r e n t scour, s to rm su rg i ng , and r e l e a s e of h i o g e n i c gas.

S i ng le - kee led and m u l t i k e e l e d i c e f l o e s d r i v e n by wind and wate r c u r r e n t s

f u r r o w t h e s e a f l o o r p a r a l l e l t o t h e ba thyme t r i c con tours . These f u r rows occur

i n wa te r depths down t o 79 f e e t , and a r e most dense between depths o f 32 and 56

f e e t . The No. 2 w e l l i s l o c a t e d i n a r e l a t i v e l y i n t e n s e i ce -goug ing zone caused

b y the westward-movi ng i c e pack o f Nor ton Sound shea r i ng a g a i n s t t h e s h o r e f a s t

i c e t h a t extends o f f s h o r e from t h e d e l t a . The s i n g l e - k e e l e d i c e gouges i d e n t i f i e d

by s ide-scan sonar range i n w i d t h from 16 t o 164 f e e t and a r e seldom g r e a t e r

t h a n 3 f e e t deep. A c t i v e sed imenta t ion i n f i l l s t h e gouges i n t h e r i ve r -dom ina ted

months o f summer.

Trans ien t f e a t u r e s such as c u r r e n t scour, ~ n e g a r i p p l es, and l o n g i t u d i n a l

c u r r e n t l i n e a t i o n s were n o t found a t t h e d r i l l s i t e , b u t were found i n a

l i m i t e d e x t e n t n o r t h of t h e we1 1 s i t e and j u s t west o f t h e d e l t a . Cu r ren t scour

i s c h a r a c t e r i z e d by e longa ted depress ions 330 t o 490 f e e t l ong , 115 t o 330 f e e t

wide, and l e s s than 6 f e e t deep. They para1 l e l t h e dominant bo t tom-cur ren t

d i r e c t i o n and rework t h e unconso l ida ted s i l t y f i n e sand compr i s i ng t h e l o c a l

s u r f a c e sediments. Megar ipp les occur as a s e r i e s o f r i p p l e s hav ing a wavelength

o f 65 t o 165 f e e t and an amp l i tude o f l e s s than 1.5 fee t , They occur i n a s u b t l e

ba thy rne t r i c t r ough n o r t h o f t h e w e l l s i t e , and t h e i r c r e s t s a re norrnal t o the

dominant westward bo t tom-cur ren t d i r e c t i o n , L o n g i t u d i n a l c u r r e n t l i n e a t i o n s

occur as a s e r i e s o f fu r rows hav ing a wavelength of 30 t o 100 f e e t and depths o f

l e s s t han 1.5 f ee t . The l i n e a t i o n s p a r a l l e l t h e dominant bo t tom-cur ren t d i r e c t i o n

and occur j u s t sou th o f t h e megar ipp l es.

Degassing o f b i o g e n i c gas generated by b u r i e d Holocene peat l a y e r s r e s u l t s

i n gas c r a t e r i n g i n t h e eas te rn h a l f o f Nor ton Sound. The c r a t e r i n g i s u s u a l l y

l e s s than 1.5 f e e t i n r e l i e f and on s ide-scan sonograms appears as a pa tchy

t e x t u r a l f ea tu re .

Qua te rna ry Geology

Nor ton Sound was s u b a e r i a l l y exposed i n t h e l a t e P l e i s t o c e n e owing t o a

1 owered sea 1 eve1 , Quate rnary sediments cons i s t of fl u v i a1 d e p o s i t s of cl ayey

s i l t t o s i l t y sand w i t h v a r y i n g amounts o f wood fragments, s h e l l s , and o rgan i c

ma t t e r . About 10,000 t o 9,500 y r B.P., t h e sea t r ansg ressed ove r Nor ton Sound

and began rework ing and bu ry i ng t und ra peat depos i t s (Nelson, 1980). These

o rgan i c depos i t s represen t a sea- leve l s t i l l s t a n d 60 t o 80 f e e t below presen t

sea l e v e l and a r e t h e base of t h e Holocene. Transgress ion r e s u l t e d i n Holocene

depos i t s r ang ing f rom a f i n e sand i n t h e n o r t h e r n h a l f o f t h e s a l e area t o

c l a y e y s i l t near t h e Yukon De l t a . Approx imate ly 32 t o 40 f e e t below presen t

sea l e v e l , a younger, l e s s ex tens i ve , o r g a n i c - r i c h l a y e r i s found ex tend ing

seaward f rom t h e Yukon D e l t a . Th i s represen ts a l a t e r s t i l l s t a n d t h a t a l lowed

t h e development o f t und ra peat. Subsequent t r a n s g r e s s i o n over t h e area reworked

and b u r i e d t h e peat r e s u l t i n g i n an o r g a n i c - r i c h s i l t depos i t . Th i s depos i t

grades upward i n t o c l a y e y s i l t i n t h e west and a s i l t y sand i n t h e east. The

b u r i e d o r g a n i c - r i c h d e p o s i t s a r e c u r r e n t l y gene ra t i ng gas as i n d i c a t e d by t h e

gas c r a t e r i n g and by ex tens ive , sha l low acous t i c anomalies t h a t occur on bo th

t h e processed and analog records of t h e m i n i s p a r k e r and watergun systems.

SEISMIC REFLECTION CORRELATION

AND

VELOCITY ANALYSIS

by Dav id S t e f f y

By t h e use o f v e l o c i t y i n f o r m a t i o n f ro in t h e Nor ton Sound COST Nos. 1 and

2 w e l l s and a 1978 USGS se ismic r e f l e c t i o n survey ( f i g . 6 ) , se ismic c o r r e l a t i o n s

and v e l o c i t i e s f rom t h e 2 w e l l s were compared t o each o t h e r and t o those f rom

t h e nearby se ismic l i n e s . The s t a c k i n g v e l o c i t i e s used on t h e common-depth-point

(CDP) t r a c e s were eva l uated be fo re s t a c k i n g t h e gathers . These comparisons

were used t o ass i gn geo log i c s i g n i f i c a n c e t o f e a t u r e s i d e n t i f i e d on t h e p r o f i l e s ,

and t h e s i g n i f i c a n t f ea tu res were used t o e s t a b l i s h t h e geo log i c h i s t o r y o f

Nor ton Bas in i n t h e conc lud ing s e c t i o n o f t h i s r e p o r t .

Seismic Ref1 e c t i o n C o r r e l a t i o n

A s y n t h e t i c seismogram was produced by use o f borehole-compensated, i n t e r v a l -

t r a n s i t - t i m e l o g o f t h e No. 2 w e l l , ( f i g . 7) . The son i c l o g was v i s u a l l y

averaged w h i l e b e i n g s t ream d i g i t i z e d dnd was measured t o t h e neares t f o o t i n

dep th and t h e nea res t microseconds/ foot i n t r a n s i t t ime. T h i s r e s u l t e d i n l u g

samples b e i n g t aken a t i r r e g u l a r i n t e r v a l s . However, t h e sampl ing was f r equen t

enough t o p reven t a l i a s i n g i n t h e seismogram. The d i g i t i z e d da ta were then

en te red i n t o a computer program t h a t produced a s y n t h e t i c seismogram w i t h o u t

m u l t i p l e s , Constant d e n s i t y was assumed, t h e r e f o r e d e n s i t y was n o t i n c o r p o r a t e d

i n t o t h e c a l c u l a t i o n o f t h e r e f l e c t i o n c o e f f i c i e n t s . T h i s assumption a p p a r e n t l y

does n o t adve rse l y a f f e c t t h e r e s u l t s of t h e s y n t h e t i c seismogram i n a s imp le

geo log i c s e t t i n g (She r i f f, 1978). The cornputer program a1 so assumes a s e r i e s

o f h o r i z o n t a l , p a r a l l e l e a r t h l a y e r s w i t h an e l a s t i c cons tan t , and assumes

t h a t t h e i n c i d e n t waves a r e normal t o t h e r e f l e c t i n g s u r f a c e and have p l a n a r

wavef ronts . The c a l c u l a t e d r e f l e c t i o n c o e f f i c i e n t s were then convolved w i t h a

s tandard r i c k e r wave le t hav ing a f requency range o f 8-55 Hz. Th i s c o n v o l u t i o n

r e s u l t s i n a seismogra~n t h a t i s d i s p l a y e d w i t h b o t h normal and reve rse p o l a r i t y .

The s y n t h e t i c seismogram was then c o r r e l a t e d t o t h e 1977 Western Geophysical

se ismic l i n e WNS-24 which p r o f i l e s th rough t h e we1 1 l o c a t i o n ( f i g , 7 ) . By use

o f t h i s c o r r e l a t i o n , f o u r d i s t i n c t ho r i zons a re i d e n t i f i e d i n o r d e r t o r ep resen t

t h e s t r u c t u r a l and s t r a t i g r a p h i c c o n f i g u r a t i o n o f t h e bas in , Three o f t h e

@ f o u r ho r i zons a r e con t inuous t o t h e No. 1 w e l l , where d s i m i l d r l y d e r i v e d

s y n t h e t i c seismogram was used. F i gu res 8, 9, and 10 a r e USGS se ismic l i n e s

807, 813, and 802, r e s p e c t i v e l y , which were surveyed near t h e w e l l s and t h a t

d i s p l a y these hor i zons . L i n e 807 i s a n o r t h - s o u t h p r o f i l e t h rough t h e S t u a r t

subbasin. The l i n e p r o f i l e s w i t h i n one rn i l e o f t h e No. 2 w e l l a t CDP ga the r

1004. L i n e 802 i s a no r t h - sou th p r o f i l e th rough t h e St. Lawrence subbasin.

The l i n e p r o f i l e s w i t h i n one m i l e o f t h e No. 1 w e l l a t CDP g a t h e r 2240. L i n e

813 i s an east -west p r o f i l e across t h e S t u a r t subbasin, t h e Yukon h o r s t , and

t h e St. Lawrence subbasin. The l i n e p r o f i l e s w i t h i n 4 m i l e s o f t h e No. 2

w e l l and w i t h i n 16 m i l e s o f t h e No, 1 w e l l a t CDP ga thers 1740 and 120,

r e s p e c t i v e l y . F i g u r e 11 d i s p l a y s the t i m e - s t r a t i g r a p h i c column o f t h e No. 2

we1 1 based on desc r i bed i n t h e Pa leon to logy and R i o s t r a t i g r a p h y s e c t i o n o f

t h i s r e p o r t .

0

Seismic Profile

4

a3 c 91 0 m + V) .- m - P

0 e w

C 0 w

0 .- - m a b

e m e a3

l 0 'VVVVI 0

f 4

aa C a2 U 0 Q) .- 6

w C a V 0

W

L 0

g k g

W

Probable P a l e o z o i c

horizon D

horizon C

horizon 6- I

horizon A

Figure I I . T irne-stratigraphic column and seismic prof i le o f COST No. 2 well

26

• Hor izon A occurs a t 3.57 seconds o r 14,460 f e e t i n t h e No. 2 w e l l , and

a t 3.1 0 seconds o r 12,550 f e e t i n t h e No. 1 we1 1. The h o r i z o n i s c h a r a c t e r i z e d

by l a r g e ampl i tude, 1 ow frequency r e f 1 e c t i o n s t h a t a re most1 y d i scont i nuous.

Below t h e h o r i z o n t h e r e a r e few areas i n t h e b a s i n where r e f l e c t i o n s occur.

Above t h e h o r i z o n t h e r e f l e c t i ons d i s p l a y an on lap r e l a t i o n s h i p . The ho r i zon

represen ts an u n c o n f o r ~ n i t y t h a t separates t h e base of t h e b a s i n f i l l f r om t h e

u n d e r l y i n g metamorphic basement rock. Hor izon A i s c o r r e l a t e d between t h e

w e l l s and d i s p l a y s ~ n a j o r s t r u c t u r a l de fo rmat ion o f an e a r l y T e r t i a r y t o l a t e

Mesozoic e ros iona l su r face , Th i s de fo rmat ion i n i t i a t e d t h e subsidence of t h e

S t . Lawrence and S t u a r t subbasins. D u r i n g t h e subsidence, and t h e i r common

border , t h e nor th -sou th t r e n d i n g Yukon h o r s t , was a r e l a t i v e l y h i gh basement

f e a t u r e ( f i g . 9). Normal f au l t i n g de1 i n e a t e s the s t r u c t u r a l depress ions w i t h i n

a t h e subbasins, and t h e Yukon h o r s t . Some o f these f a u l t s were a c t i v e i n t o t h e

P le i s tocene and p robab ly t h e Holocene (Hoose, S t e f f y , and Lybeck , 1981 ) . Normal f a u l t s ~ i t h d isp lacements o f over 4500 f e e t o f f s e t h o r i z o n A. Downwarping

o f t h e h o r i z o n a l lowed over 14,000 f e e t o f sedimentary fill t o accumulate i n

t h e S t u a r t subbasin.

Hor izon B-1 occurs a t 3.12 seconds o r 12,700 f e e t i n t h e No. 2 w e l l . The

ho r i zon i s c h a r a c t e r i z e d by l a r g e ampl i t u d e , 1 ow f r eque r~cy r e f l e c t i o n s . There

a r e few r e f l e c t i o n s j u s t below t h e hor i zon , and those t h a t do occur have v a r i a b l e

ampl i tude and a r e d iscon t inuous . Th is ho r i zon i s an apparent unconformable

s u r f a c e t h a t on1 aps ho r i zon A a t s t r u c t u r a l h i ghs and r e f 1 e c t s syndeposi t i o n a l

subsidence and f a u l t i n g . Hor izon B-1 i s n e i t h e r con t inuous throughout t h e S t u a r t

subbasin n o r c o r r e l a t e d t o any s p e c i f i c h o r i z o n i n t h e No. 1 w e l l . A t t h e No.

2 w e l l , t h e h o r i z o n d e f i n e s t h e t o p o f an Eocene coal -sandstone sequence t h a t

i s bounded a t t h e bot tom by ho r i zon A.

Hor izon C occurs a t 2.33 seconds o r 8,500 f e e t i n t h e No, 2 w e l l , and a t

2.41 seconds o r 8,620 f e e t i n t h e No. 1 we l l . I n t h i s S t u a r t subbasin, t h i s

h o r i z o n i s t h e boundary between a deeper zone of smal l e r ampl i tude, d i s c o n t i nuous

r e f l e c t i o n s and a sha l l owe r zone o f l a r g e r amp1 i t u d e , con t inuous r e f l e c t i o n s .

Bo th zones o f r e f l e c t i o n s a r e conformable t o h o r i z o n C i n t h e b a s i n and t h i n

towards s t r u c t u r a l h i ghs where t h e l owe r zone onlaps ho r i zons B-1 and A.

Hor izon C i s con t inuous th roughout t h e b a s i n and i s c o r r e l a t e d t o t h e No. 1

w e l l , I n t h e St. Lawrence subbasin, t h e h o r i z o n i s n o t as d i s t i n c t as i t i s

i n t h e S t u a r t subbasin. Both the deep and sha l l ow zones o f r e f l e c t i o n s i n t h e

S t . Lawrence subbasin a r e more d i scon t i nuous and have sma l l e r and more v a r i a b l e

ampl i t u d e s than t h e i r e q u i v a l e n t s i n t h e S t u a r t subbasin. Throughout t h e

bas in , t h e h o r i z o n shows syndeposi t i o n a l warping and f a u l t i n g and pinches ou t

a t some s t r u c t u r a l h ighs , i n c l u d i n g t h e Yukon ho rs t . A t t h e No. 1 w e l l t h e

ho r i zon c o r r e l a t e s w i t h a s h e l f a l mar ine mudstone, sha le , and in te rbedded

sandstone sequence. A t t h e No. 2 w e l l t h i s h o r i z o n i s c o r r e l a t e d t o t h e boundary

between an o v e r l y i n g mar ine sandstone and an u n d e r l y i n g coal -sandstone sequence.

Hor izon D occurs a t 1.18 seconds o r 3,490 f e e t i n t h e No. 2 we1 1 , and

1.42 seconds o r 4,490 f e e t i n t h e No. 1 we l l . Throughout t h e b a s i n t h i s h o r i z o n

separates a deeper zone o f 1 arge amp1 i tude, h i g h f requency, con t inuous r e f l e c t i o n s

f rom a s h a l l ower zone o f smal l amp1 i t ude, d i s c o n t i nuous r e f l e c t i ons. The

h o r i z o n i s a conformable su r f ace th roughout t h e b a s i n and i s c o r r e l a t i v e w i t h

a l a t e Ol igocene coal -sandstone sequence. The h o r i z o n i s commonly o f f s e t by

normal f a u l t s t h a t a r e younger than ho r i zon C.

V e l o c i t y Ana l ys i s

RMS ve l o c i t i e s , i n t e r v a l v e l o c i t i e s and a t ime-depth curve were c a l c u l a ted

( f i g s . 12 and 13) u s i n g t h e i n t e r v a l - t r a n s i t - t i m e l o g o f t h e No. 2 w e l l . A

comparison i s made between these and s i m i l a r v e l o c i t i e s and a t ime-depth curve

t h a t were c a l c u l a t e d f rom nearby se ismic r e f l e c t i o n data. I n f l a t - l y i n g p a r a l l e l -

bedded s t r a t a , t h e RMS v e l o c i t i e s d e r i v e d f rom a son ic l o g a r e comparable t o

t h e s t a c k i n g v e l o c i t i e s t h a t a r e used t o c o r r e c t f o r normal rnovernent o f CDP

t races . F i g u r e 12 d i sp lays t h i s comparison. S tack ing v e l o c i t i e s f o r USGS

1 i n e s 81 3 and 814 t h a t were shot w i t h i n 5 m i l e s o f t h e we1 1 were p i cked and

averaged. Down t o 1.75 seconds o r 6,000 f e e t , t h e two types o f v e l o c i t i e s a r e

i n good agreement. Below 1.75 seconds, t h e s t a c k i n g v e l o c i t i e s become i n c r e a s i n g l y

h i g h e r than t h e RMS v e l o c i t i e s . Anstey (1977) p o i n t e d o u t t h a t s t a c k i n g v e l o c i t i e s

and borehol e v e l o c i t y f i n d i n g s rn i ght n o t agree because o f geornet r i c and nongeolnet r i c

d i f f e r e n c e s i n t h e da ta c o l l e c t i o n methods. I n t h i s case, t h e d i f f e r e n c e

below 1.75 seconds i s p a r t i a l l y exp la i ned by d i p p i n g r e f l e c t o r s . R e f l e c t i o n s

w i t h d i p s o f up t o 25' a r e p resen t where some o f t h e v e l o c i t y spec t ra were

--- Stecklng Veloclty

RMS Velocity

5,000 8.000 7.000 8,000 9,000 10.000

VELOCITY (feetlsecond)

Figure 12. Comparison between stacking velocities and RMS velbcities for COST No. 2 well

32

TWO-WAY TIME (aeconda) 0 1.0 2 -0 3 -0 4.0

S,OOO 10,000 15,000 20,000 25.000

INTERVAL VELOCITY (feet/second)

F i g u r e 13. I n t e r v a l v e l o c i t i e s a n d t i m e - d e p t h c u r v e f r o m s o n i c l o g o f

COST N o . 2 we l l 33

d isp layed . Also, a t 2.94 seconds o r 12,500 f e e t , t h e RMS v e l o c i t y cu r ve becornes

cons tan t a t 8800 t o 8850 fee t l seconds . Th i s i s app rox ima te l y where h o r i z o n

B-1 i s l o c a t e d , which d e f i n e s t h e t o p of a coa l -sandstone sequence. The low-

d e n s i t y c o a l s and i n t e rbedded gaseous sandstones reduced t h e i n t e r v a l v e l o c i t i e s

o f t h i s sequence. There fo re , t h i s sequence has l o w e r RMS v e l o c i t i e s .

A f t e r a d j u s t i n g t h e s t a c k i n g v e l o c i t i e s f o r d i p , i n t e r v a l v e l o c i t i e s and a

t i rne-depth cu rve were c a l c u l a t e d ( f i g . 14). Down t o 9200 f e e t , t hese i n t e r v a l

v e l o c i t i e s are i n c l o s e agreement w i t h t hose c a l c u l a t e d f r om son i c da ta ( f i g . 13) .

Be1 ow 9200 f e e t , t h e i n t e r v a l v e l o c i t i e s d e r i v e d f rom s e i smic r e f 1 e c t i o n da ta

a r e c o n s i s t e n t l y h i g h e r than those d e r i v e d f rom son i c data. Th i s d i f f e r e n c e

i n i n t e r v a l ve l oc i t i e s causes a d ive rgence i n t h e i r co r respond ing t ime-dep th

cu r ves ( f i g . 15) . The d i f f e r e n c e i s probably due t o geometric and nongeornetric

d i f f e rences i n da ta c o l l e c t i o n methods.

F i g u r e 16 i s a comparison of t h e t ime-dep th cu rves d e r i v e d f rom se is in i c

r e f l e c t i o n da ta c o l l e c t e d near t h e we l l s . Down t o 5,000 f e e t t h e cu rves a r e

i n good agreement. Below 5,000 f ee t , t h e No. 2 w e l l d i s p l a y s a s teeper t ime -

depth curve. These h i g h e r v e l o c i t i e s a r e p robab l y due t o l i t h o l o g i c d i f f e rences

i n t h e w e l l s between 5,000 and 10,000 f ee t . I n t h i s i n t e r v a l t h e No. 2 w e l l

pene t ra ted a coa l -sandstone sequence t h a t has a h i g h e r average i n t e r v a l v e l o c i t y

t han t h e mar ine sediments found i n t h e No. 1 w e l l . From 10,000 t o about

12,550 f e e t , t h e i n t e r v a l v e l o c i t i e s a r e approx imate ly t h e same. Be1 ow 12,550

f e e t , t h e No. 1 we1 1 i n t e r v a l v e l o c i t i e s r e f l e c t an a c o u s t i c basement o f metamorphic

rock, whereas t h e No. 2 w e l l i n t e r v a l v e l o c i t i e s r e f l e c t a r e l a t i v e l y l owe r

TWO-WAY TIME (seconds)

INTERVAL VELOCITY (feet/aecondl

F i g u r e 14. I n t e r v a l v e l o c i t i e s a n d t i m e - d e p t h c u r v e f r o m s e i s m i c

n e a r COST N o . 2 w e l l

d a t a

1 .O 2 -0 3.0 4.0

TWO-WAY TIME (seconds)

F i g u r e 15. Comparison b e t w e e n t i m e - d e p t h c u r v e s d e r i v e d f r o m s e i s m i c and s o n i c d a t a f o r C O S T No.2 w e l l

--- Coat Well 2

Coat Well 1

TWO-WAY TIME (aeconds)

FIGURE 16 - COMPARISON BETWEEN TIME-DEPTH CURVES FOR COST WELLS I AND 2

v e l o c i t y coa l -sandstone sequence down t o a dep th o f 14,460 f e e t . Below 11,460

f e e t t h e i n t e r v a l v e l o c i t i e s r e f l e c t t h e metamorphic r ock o f a c o u s t i c basement,

Therefore, any t ime-dep th convers ions shou ld cons ide r t h e l i t h o l o g i c d i f f e r e n c e s

i n t h e wells below 5,000 f ee t . The d i f f e r e n c e s p robab l y r e f l e c t t h e i n d i v i d u a l

subbasin h i s t o r i e s . Below 5000 f e e t v e l o c i t y v a r i a t i o n s w i t h i n each subbas in

p robab l y w i l l n o t be a s g rea t as v e l o c i t y v a r i a t i o n s between t h e subbasins.

PALEONTOLOGY AND BIOSTRATIGRAPHY

by

Ronald F. Turner

Pal eoecol o g i c and b i o s t r a t i g r a p h i c de te rm ina t i ons i n t h e ARC0 Nor ton Sound

COST No. 2 Well a r e based on d e t a i l e d analyses o f m i c r o f o s s i l assemblages

c o n t a i n i n g Fo ram in i f e ra , s i 1 i c o f l age1 1 a tes and d i atoms, c a l careous nannopl ankton,

and mar ine and t e r r e s t r i a l palynomorphs. Rotary d r i l l b i t c u t t i n g s were exami ned

a t 30- foot i n t e r v a l s f rom t h e f i r s t sample a t 450 f e e t t o t h e t o t a l depth o f

14,889 f e e t . Data f rom convent iona l and s i d e w a l l co res were a l s o examined

and u t i l i zed . I n a d d i t i o n , sl i des , processed samples, and r e p o r t s prepared f o r

t h e p a r t i c i p a n t s by c o n s u l t a n t s ( B i o s t r a t i g r a p h i c s , 1982) were examined,

i n t e r p r e t e d , and i n t e g r a t e d i n t o t h i s r e p o r t . D isc repanc ies between M ine ra l s

Management Se rv i ce and c o n s u l t a n t i n t e r p r e t a t i o n s , p r i n c i p a l l y t h e l o c a t i o n o f

b i o s t r a t i g r a p h i c tops , f o r t h e most p a r t can be a t t r i b u t e d t o sample con ten t

v a r i a t i o n s and d i f f e rences i n sampl e p r e p a r a t i o n techniques. Forami n i f e r a l

a n a l y s i s , i n t e r p r e t a t i o n , and syn thes i s o f o t h e r da ta were done by t h e author .

S i l i c e o u s ~ n i c r o f o s s i l a n a l y s i s was done by Donald L. Olson.

S t r a t a a r e d iscussed i n t h e o rde r t h a t they were penetrated. The

b i o s t r a t i g r a p h i c u n i t s d e l i n e a t e d represen t a syn thes i s o f da ta d e r i v e d f rom

var ious s u b d i s c i p l i n e s t h a t do n o t agree i n every p a r t i c u l a r . Sample depths

may d i sag ree s l i g h t l y w i t h measured depths, Fo l l ow ing convent ion, f o s s i l

occurrences a r e l i s t e d as h i ghes t and lowes t r a t h e r t han t h e p o t e n t i a l l y

con fus ing f i r s t and l a s t . Data ob ta i ned f rom cores a r e g i ven somewhat more

we igh t than those f rom c u t t i n g s . C o r r e l a t i o n w i t h t h e o t h e r Norton Sound

COST we l l i s d iscussed a t t h e conc lus ion of t h i s r epo r t .

Pal eoenvi ronmental determi na t i ons a r e based on t h e e n t i r e and macrofoss i 1

m i c r o f o s s i l s u i t e s . Pal eoc l i ~ n a t o l o g i c a l i n t e r p r e t a t i o n s a r e based on spore

and p o l l e n assemblages and, t o a l e s s e r ex ten t , on diatoms, s i l i c o f l agellates,

and Foramin i fe ra . Fl u v i a l , l a c u s t r i n e , and p a l udal env i ronments a r e c l a s s i f i e d

as c o n t i n e n t a l o r nonmarine. T r a n s i t i o n a l environments a r e b r a c k i s h e s t u a r i e s ,

marshes, and hypersa l i n e and hyposa l i ne 1 agoons. F o r sediments depos i t ed i n

mar ine environments, t h e paleoenvironment i s expressed i n terms of bathymetry.

Paleobathyrnet r ic de te rm ina t i ons a r e p r i r na r i l y based on f o r a m i n i f e r a 1 c r i t e r i a ,

b u t d i n o f l a g e l l a t e s and o t h e r mar ine organisms such as bryozoans, ech ino ids ,

ophuro ids, and c i r r i p e d s a re a l s o u t i l ized. The mar ine environment i s d i v i d e d

i n t o i n n e r n e r i t i c (0-60 f e e t ) , m idd le n e r i t i c (60-300 f e e t ) , o u t e r n e r i t i c

(300-600 f e e t ) , and upper ha thya l (600-1500 f e e t ) .

Pl e i stocene

The i n t e r v a l f rom 450 t o 1320 f e e t i s cons idered t o be P le i s tocene i n age

on t h e b a s i s o f a f o r a m i n i f e r a 1 fauna c h a r a c t e r i z e d by E lph id i um clavatum,

E l ph id ium b a r t l e t t i , Pro toe l p h i d i um o r b i c u l a r e , E l p h i d i e l l a gorbunovi , E l p h i d i e l l a

oregonense, E l p h i d i e l l a hannai, Bucce l l a f r i g i d a , and Q u i n q u e l c u l i n a akner iana.

Rare, p o o r l y preserved and broken ost racodes ass ignab le t o Pa racyp r i de i s

p s e u d o p u n c t i l l a t a , "Acan thocy there is " dunelmensis, and R a b i l i m i s s e p t e n t r i o n a l i s

s u b s t a n t i a t e a P le i s tocene age.

The d ia tom assemblage i s q u i t e sparse, b u t t h e presence o f M e l o s i r a s u l c a t a

t o some degree suppor ts a P le i s tocene age. Spores and p o l l e n a r e a l s o r a r e , bu t

@ an assemblage composed o f Sphagnurnspori t e s spp., A1 n ip01 1 en i t e s sp., and Be tu l aceae

and Compositae (He l i an thus t y p e ) i s c o n s i s t e n t w i t h a P le i s t ocene age. No

ca lcareous nannoplankton o r r a d i o l a r i a n s were recovered i n t h i s i n t e r v a l .

Envi ronment

The m i c r o f o s s i l assemblage i n d i c a t e s t h a t t h e P le i s tocene sediments were

depos i ted i n c o l d water a t i n n e r n e r i t i c depths (0-60 f e e t ) . S a l i n i t y v a r i e d

f rom normal mar ine t o b rack ish .

P I i ocene

The i n t e r v a l f rom 1320 t o 2580 f e e t i s here considered t o represent t h e

Pl iocene s e c t i o n o f t h e we1 1. The b i o s t r a t i g r a p h i c s i l iceous m i c r o f o s s i l

zonat ion u t i 1 i zed hereaf te r t o l l ows t h a t o f Koizumi (1973), Schrader (1973) and

Barron (1 980). The Pl iocene sec t i on can be on l y p r o v i s i o n a l l y f u r t h e r subdivided

owing t o t h e poo r l y known b i o s t r a t i g r a p h y o f t h e area and compl ica t ions caused

by ex tens ive reworking and downhole contaminat ion.

The l a t e Pl iocene, 1320 t o 1846 f e e t , i s de f i ned by t h e h ighes t occurrences

o f t h e diatoms Coscinodiscus marginatus f o s s i l i s , Coscinodiscus pus tu la tus ,

Stephanopyxis ho r r i dus , and Thal ass ios i r a zabel inae. Rare specimens o f

Den t i cu lops i s kamtschat ica recovered from a s idewal l core a t 1846 f e e t mark

t h e t o p o f t h e middle Pliocene. The base of t h i s i n t e r v a l i s t e n t a t i v e l y

p laced a t 2228 f e e t on t h e bas i s of t h e h ighes t occurrence o f the e a r l y Pl iocene

forms Cosmiodiscus i n s i gnis and Thal ass ios i r a punctata. The early P l iocene

sec t ion , 2228 t o 2580 f e e t , i s based on t h e h ighes t occurrences o f the afore-

mentioned d iatom species and an assemhl age charac ter ized by Cosci nodi scus

ten~pere i and t he s i l i c o f l a g e l l a t e Eb r iops i s ant iqua.

The t e r r e s t r i a1 pa lynof l ora conta ins re1 a t i ve l y abundant speci~nens o f

A l n i p o l l e n i t e s sp., Osmundacites sp., and r a r e t o f requent Betulaceae,

Polypodi aceae, Pol emoni aceae, Composi tae, and Ma1 vaceae.

0 The mar ine component of t h e p a l y n o f l o ra i n c l u d e s t h e d i n o f l age1 1 a tes L e j u n i a

spp., S p i n i f e r i t e s spp., and Cannosphaeropsis a f f . - C. sp. A Wi l l i ams and

Br ideaux 1975. The h ighes t occurrence of t h e l a t t e r species, 231 0 f e e t , i s

cons idered a p o s s i b l e Miocene marker by t h e c o n s u l t a n t s on t h e b a s i s of t h e

occur rence o f Cannosphaeropsis sp. A i n t h e Miocene o f eas te rn Canada.

The c o n s u l t a n t s a l s o i d e n t i f y a Tasmanaceae zonule between 2040 and 2670 f e e t

t h a t t hey cons ide r t o be P l i ocene t o Miocene i n age.

The f o ram in i f e ra1 fauna con ta ins a l l o f t h e spec ies p resen t i n t h e

P l e i stocene sec t i o n as we1 1 as Pseudopolyrnorphi na sp., Denta l i na sp. ,

Quinque locu l i n a seminul um, Globobul im ina sp., E l p h i d i e l l a s i b i r i c a , E l p h i d i e l l a

c f - E. brunescens, E lph id i um incer tum, Cass idu l i na c f . C. minuta, P u l l e n i a sp.,

and 001 i n a melo. -

Envi ronment

D e p o s i t i o n took p l a c e a t i n n e r n e r i t i c depths i n a c o l d water environment

c h a r a c t e r i z e d by f l u c t u a t i n g s a l i n i t i e s . The che i los tome bryozoan fragments

recovered i n c l u d e b o t h e n c r u s t i n g and e r e c t co lon ies . The presence o f

c e l l a r i i form and c a t e n i c e l l i fo rm z o a r i a l t ypes ( e r e c t w i t h f l e x i b l e i n te rnodes )

suggests a d e p o s i t i o n a l env i ronrnent c h a r a c t e r i z e d by modera te ly s t r o n g c u r r e n t s

and a r e l a t i v e l y h i g h sed imenta t ion ra te . S t rong l y s tenohal i n e forins such as

ech ino ids and ophuro ids a r e p resen t th roughout t h e i n t e r v a l , b u t a re n e i t h e r

d i v e r s e n o r numerous.

lli ocene

The i n t e r v a l f r om 2580 t o 3524 f e e t i s Miocene i n age. The s e c t i o n i s

subd iv ided i n t o l a t e and e a r l y Miocene on t h e b a s i s o f s i l i c e o u s m i c r o f o s s i l

assemblages. The l a t e Miocene, 2580 t o 3120 f e e t , i s based on t h e lowes t

occurrence o f T h a l a s s i o s i r a zabe l inae and t h e h i g h e s t occurrences o f Rhaphoneis

s u r i r e l l a and Goniothecum tenue assoc ia ted w i t h Cosc inodiscus ve tus t i s s imus ,

and Coscinodiscus temperei . No i n s i t u m idd le Miocene forms a r e p resen t and

i t i s p o s s i b l e t h a t t h i s t ime i s represen ted by a h i a tus . The e a r l y Miocene,

31 20 t o 3524 f e e t , i s c h a r a c t e r i z e d by T h a l a s s i o t h r i x long iss ima, Rhaphoneis

miocenica, Rhaphoneis c f . - R. f o s s i l i s , and Ac t i nocyc l us ingens.

The spore-po l len assemblage i s q u i t e s i m i l a r t o t h a t i d e n t i f i e d i n the

o v e r l y i n g P l iocene sec t ion . The d i n o f l agel 1 a t e assembl age c o n t a i n s L e j u n i a

pa ra tene l 1 a, L e j u n i a spp., S p i n i f e r i t e s c i n g u l a t u s , S p i n i f e r i t e s ramosus,

Tubercu lod in ium vancampoe, and Hys t r i chosphaerops is sp. The d i n o c y s t s t r a t i g r a p h y

suppor ts t h a t d e r i v e d f r o m diatoms and s i l i c o f l agel l a t e s .

The f o ram in i f e ra1 assernbl age i s s i m i l a r t o t h e Elph id ium-El p h i d i e l l a

dominated faunas seen h ighe r i n t h e w e l l and con ta ins a1 1 o f t h e same species.

New taxa i n c l u d e C r i b r o e l p h i d i u m crassum, ~ u i n q u e l o c u l i n a s a c h a l i n i c a , Oen ta l i na

a f f. D. nasuta, E l p h i d i e l l a s implex, ,E l p h i d i e l l a ka tang l i e n s i s , Pseudogl andul i n a - sp., Pseudoglandul ina a f f . - P. n a l l p e e n s i s , E l l i p s o g l a n d u l i n a c f . - E, subobesa,

S ig rno ide l la p a c i f i c a , and P o r o s o r o t a l i a c l a r k i . Th i s assemblage, here cons idered

t o represen t m idd le t o e a r l y Miocene, i s bes t developed f rom 3200 t o 3540

f ee t . Species such a s E l p h i d i e l l a ka tang l i e n s i s , Porosoro ta l i a c l a r k i , and

Qu inque locu l i na s a c h a l i n i c a were desc r i bed f rom d e p o s i t s o f supposed l a t e

Miocene age on Sakha l i n I s l a n d , U.S.S.R. (Voloshinova, and o thers , 1970).

Subsequent s t r a t i g r a p h i c r e v i s i o n s (Serova, 1976; Gladenkov, 1977; Menner, and

o the rs , 1977) p l a c e these s t r a t a i n t h e m idd le Miocene, and i t i s q u i t e p o s s i b l e

t h a t t h e y may prove t o be o l de r . Several o f t h e spec ies appear t o range th rough

t h e Ol igocene s e c t i o n and may extend i n t o t h e Eocene as w e l l .

The l a t e Miocene i n t e r v a l was depos i t ed i n i n n e r t o rniddle n e r i t i c depths

(0-300 f e e t ) i n a c o l d c l ima te . The ear ly Miocene i n t e r v a l r ep resen ts a

shal lower ( i n n e r n e r i t i c ) and warmer env i ronrnent (warm-temperate t o s u b t r o p i c a l ).

01 i gocene

The i n t e r v a l f r o m 3524 t o 10,160 f e e t i s cons idered t o . b e Ol igocene i n

age, The p a l y n o f l oras over t h i s i n t e r v a l a r e abundant, d i ve rse , and re1 a t i v e l y

d i agnos t i c . The uppermost coa l -bea r i ng p o r t i o n o f t h e sequence, 3524 t o 3930

f e e t , i s c h a r a c t e r i z e d by an assemblage composed o f A l n i p o l l e n i t e s sp,,

Be tu l aceae, and r a r e t o f r equen t U lmipo l l e n i t e s sp. , Pterocaryapol 1 e n i t e s sp. ,

e and Momipi tes sp. From 3930 t o 6520 f e e t , t h e spo re -po l l en and d i n o c y s t

assembl ages a r e much more d i v e r s e and age d iagnos t i c . A d d i t i o n a l t e r r e s t r i a l

palynomorphs i n c l u d e common Caryapo l l e n i t e s sp., Jug1 anspol l e n i t e s sp.,

T i l i a e p o l l e n i t e s sp., and l e s s abundant specimens o f Faguspo l l en i t es s p . ,

I l e x p o l l e n i t e s sp., and Liquidamberpol l e n i t e s sp. The d i nocys t assemblage

c o n t a i n s Tenua c f . - T. decorata, D i s ta tod in i u rn e l l i p t i c u m , Def landrea sp., and

Para lecanice11 a i nden ta ta . Fungal palyno~norphs, p a r t i c u l a r l y spec ies of

S t r i a d i p o r i t e s , a r e an i n c r e a s i n g l y impo r tan t f l o r a l element be1 ow 7900 feet .

The c o n s u l t a n t s suggest t h a t some of t h e funga l t axa recovered below 9,300

f e e t may have Eocene a f f i n i t i e s ,

Calcareous nannoplankton a r e represented i n t h e we1 1 by a s i n g l e , incomple te

p l a c o l i t h o f Cocco l i t hus pe lag i cus f rom 7250-7340 f e e t . A morpho log ica l a n a l y s i s

o f t h e specimen suggests t h a t i t i s o l d e r than Miocene.

The f o r a m i n i f e r a 1 assecnbl age c o n t a i n s E l p h i d i e l l a ka tang l i e n s i s, E l p h i d i e l l a

c f - E. p rob lema t i ca , E l p h i d i e l l a c f . - E. tenera , E l p h i d i e l l a c f . - E. c a l i f o r n i c a ,

Cri b roe lph id i um c f . - C. crassum, C r i b r o e l ph id ium c f . - C. vu l gare, Buccel l a

m a n s f i e l d i , Porosoro ta l i a c l a r k i , Rota l i a japon ica , Ro ta l i a j apon i ca v a r i a n t a ,

Qu inque locu l i n a sp., M i l iamnia fusca, Bul i m i n e l l a c u r t a , Caucasina eocenica

kamchatica, Caucasi na b u l l a ta , Caucasi na schwageri , Reophax P l e c t i n a

Haplophragmoides spp., Cyclammina cf. - C. p a c i f i c a , Sigmomorphina suspecta,

S igmo ide l l a p a c i f i c a , Pseudoglandul i n a i n f l a t a , M a r t i n o t t i e l l a sp., Pyrgo

w i l l i a m s o n i , T r i chyohya lus b a r t l e t t i , Saccarnmina s p . , and Psarnmosphaera carnata.

Shal low wate r forms such as E l p h i d i e l l a k a t a n g l i e n s i s and P o r o s o r o t a l i a

c l a r k i dominate over much o f t h e i n t e r v a l . She l f forms such as Caucasina and

deeper wate r forms such a s Cyclammina a r e f a r l e s s common. The Caucasina

eocenica kamchat ica Zone i s r e s t r i c t e d t o t h e l a t e Eocene i n t h e U.S.S.R. and

d e f i n e s t h e Eocene-Oligocene boundary on t h e Kamchatka and I l p e n s k y pen insu las

(Serova, 1976). However, t h e severa l spec ies o f Caucasina recovered f rom t h e

Nor ton Sound No. 2 w e l l range w e l l up i n t o t h e Ol igocene.

Envi ronment

The c l i m a t e o f t he Ol igocene was s u b t r o p i c a l t o warm-temperate and t h e

bathymetry f l u c t u a t e d f rom as deep as p o s s i b l e o u t e r n e r i t i c t o c o n t i n e n t a l .

Two coal sec t i ons a r e p resen t i n t h e upper p a r t o f t h e s e c t i o n , 3424 t o 3930

f e e t and 4250 t o 4440 f ee t . These c o n t i n e n t a l t o t r a n s i t i o n a l i n t e r v a l s b racke t

an i n n e r n e r i t i c (0-60 f e e t ) section c o n t a i n i n g sha l l ow wate r f o r a m i n i f e r s

t h a t a r e common i n hyposa l ine environments. I nne r t o m idd le n e r i t i c (0-300

f e e t ) c o n d i t i o n s p r e v a i l e d f rom 4140 t o 5150 f e e t . M idd le t o o u t e r n e r i t i c

(60-600 f e e t ) c o n d i t i o n s ob ta i ned f r om 5150 t o 6770 f e e t . Poss ib l e o u t e r

n e r i t i c (300-600 f e e t ) d e p o s i t i o n a l depths a r e suggested by t h e Fo ram in i f e ra

recovered between 6290 and 6770 f ee t . Al though r a r e , i s o l a t e d specimens o f

Cyclamrnina c f . - C. p a c i f i c a and M a r t i n o t t i e l l a sp. a r e p resen t , t hey a r e n o t

assoc ia ted w i t h a t r u e deep water fauna l assemblage, The dominan t l y sha l low

wate r fauna and t h e presence o f t h i n coa l seams suggest t h a t o u t e r s h e l f , upper

s l ope d e p o s i t i o n a l depths were n o t ob ta i ned d u r i n g t h i s t r ansg ress ion . Be1 ow

6770 f ee t , t h e environment i s c h a r a c t e r i z e d by numerous f l u c t u a t i o n s f rom

c o n t i n e n t a l and t r a n s i t i o n a l t o p o s s i b l e i n n e r n e r i t i c . O v e r a l l , t h e i n t e r v a l

from 6770 t o 10,160 f e e t appears t o represen t t h e bay and marsh depos i t s o f a

t r a n s i t i o n a l env i ronment. There a r e numerous t h i n coal seams as w e l l as coa l

beds g r e a t e r than 10 f e e t t h i c k .

Eocene

The i n t e r v a l f rom 10,160 t o 12,700 f e e t i s Eocene i n age, A s u i t e o f

d i s t i n c t i v e and d i a g n o s t i c funga l palynomorphs, i n c l u d i n g Stri a d i p o r i t e s sp.,

Ctenospor i t e s wol f e i , Dice1 l a e s p o r i t e s sp. A Rouse 1977, and Pesavis t a g l u e n s i s ,

i s present . Publ ished ranges i n d i c a t e t h a t these spec ies g e n e r a l l y occur e a r l i e r

i n t h e Canadian A r c t i c than i n B r i t i s h Columbia. Presumably, t h e ranges i n

the Norton Sound area a r e somewhat i n te rmed ia te . On t h e b a s i s o f funga l

a palynon~orph ranges, t h e i n t e r v a l above 11,960 f e e t i s no o l d e r than e a r l y t o

m idd le Eocene and may be l a t e Eocene i n age. The spo re -po l l en assemblage i s

e s s e n t i a l l y t h e same as t ha t i n the o v e r l y i n g Oligocene. Mar ine palynomorphs

a r e r a r e and most a r e p robab ly caved.

Fo ram in i f e ra a r e q u i t e sparse over t h i s e n t i r e i n t e r v a l and occur most

f r e q u e n t l y between 10,160 and 12,000 f ee t . Many a r e p robab ly caved f r om uphole.

The assemblage con ta ins r a r e specimens o f Porosoro ta l i a c l a r k i , E l ph id ium

spp., E l p h i d i e l l a k a t a n g l i e n s i s , E l p h i d i e l l a c f . - E. c a l i f o r n i c a , Psammospahaera

c f . - P. carna ta , Saccammina sp., Ammodiscus sp., Loxostomurn sp., and f ragmentary

pol yinorphi nids.

A dermal scu te from a j u v e n i l e sturgeon was recovered from c u t t i n g s a t

10,160-170 f e e t . Comparisons w i t h m a t e r i a l i n t h e f o s s i l c o l l e c t i o n s o f t h e

U n i v e r s i t y o f C a l i f o r n i a a t Berkeley i n d i c a t e t h a t i t i s a species o f Acipenser

t h a t has a f f i n i t i e s w i t h an unnamed species f rom t h e e a r l y T e r t i a r y o f Montana

(P. McCl e l lan , personal communication),

Envi ronment

The Eocene depos i t i ona l environments f l u c t u a t e d between c o n t i n e n t a l

(predominant ly f l u v i a l and p a l udal ) , t r a n s i t i o n a l (marshes, hays, and e s t u a r i e s )

and i n n e r n e r i t i c . Depos i t iona l envi roninents i n t h e upper p a r t o f t h e sec t i on

(10,160-1 2,000 f e e t ) may have occasional 1y been as deep as midd le n e r i t i c

(0-300 f e e t ) . Thick coa l beds a re no t present above 12,700 f e e t , The presence o f

euryhal i ne Foramin i fe ra aszoci a ted w i t h t e r r e s t r i a1 po l 1 en and fungal p a l ynormorphs ,

pelecypod shards, s turgeon scutes, and s c a t t e r e d coal suggests a t r a n s i t i o n a l

environment. Al though sturgeon are anadromous, the j u v e n i l e s commonly i n h a b i t

s loughs near r i v e r mouths. The i n t e r v a l f rom 12,000 t o 12,700 f e e t i s dominant ly

c o n t i n e n t a l i n aspect. The c l i m a t e i n t h e Eocene was t r o p i c a l t o s u b t r o p i c a l .

Eocene o r 01 der

The i n t e r v a l f rom 12,700 t o 14,460 f e e t i s Eocene o r o lder . Palynomorph

recovery from c u t t i n g s i s poor i n t h i s p a r t o f t h e w e l l and t h e specimens are

poo r l y preserved. Al though geochemical i n v e s t i g a t i o n s i n d i c a t e a zone o f

rework ing o r a poss ib le unconformi ty between 11,960 and 12,200 f e e t , t h e

unconformi ty i s p laced a t 12,700 f e e t on t h e bas i s o f l i t h o l o g i c and d ipmeter

c r i t e r i a .

e Eocene fungal palynomorphs were recovered f r om s i d e w a l l co res b u t n o t from

conven t i ona l cores. T h i s l eaves open t h e p o s s i b i l i t y t h a t t h e s i d e w a l l co res

may have sampled contaminated mud cake.

Envi ron~nent

The t h i c k coa l sequences i n d i c a t e a c o n t i n e n t a l environment. The p a l c o c l i m a t e

was p robab l y no c o o l e r than t h a t o f t h e o v z r l y i n g t r o p i c a l Eocene sec t i on .

Metamorphic Basement

The i n t e r v a l f rom 14,460 t o 14,889 f e e t c o n s i s t s o f p h y l l i t e , q u a r t z i t e ,

and marb le s i m i l a r t o rocks o f p robab le Pa leozo i c age exposed on t h e Seward

@ Peninsu la . No i n s i t u f o s s i l s were recovered f rom t h i s p a r t o f t h e w e l l .

C o r r e l a t i o n

The s t r a t a i d e n t i f i e d i n t h e Nor ton Sound COST No. 1 and No. 2 Wel ls can

be b i o s t r a t i g r a p h i c a l l y c o r r e l a t e d d e s p i t e t h e f a c t t h a t t hey a r e l o c a t e d

app rox ima te l y 49 n a u t i c a l m i l e s a p a r t and were depos i t ed i n g e o g r a p h i c a l l y

d i s t i n c t and t e c t o n i c a l l y independent subbasins ( f i g . 17). D e p o s i t i o n a l

env i ronments a l s o d i f f e r e d . Those o f t h e S t . Lawrence subbasin, t h e s i t e

o f t h e No. 1 w e l l ( f i g , 18) , a r e more mar ine t han those o f t h e S t u a r t subbasin,

t h e s i t e o f t h e No, 2 w e l l ( f i g . 19). However, s i m i l a r i t i e s between t h e two

w e l l s a r e more pronounced than d i f f e r e n c e s , p a r t i c u l a r l y i n t h e rnarine sequences

Figure 17. B i o s t r a t i g r a p h i c C o r r e l a t i o n o f Norton Sound COST W e l l s

OLIGOCENE

EOCENE

NORTON SOUND NORTON SOUND

COST NO. 1 WELL COST NO. 2 WELL

- 0

- 450

- 1000 1320

- 2000

2 580

-3000

0- 180-

1000- 1320

2000-

2837

3000-

F l r l t Sample First Sample

PLEISTOCENE

PLIOCENE

7 MIOCENE ? -'3120 3404--

4000- - 4000

4403

6000-

6000-

7000-

8000-

9000-

SO90 10000 - ? - 7

7 '

liooO-

12000- 12235 12545

- 5000

- 8000

- 7000

- 8000

- 9000

- 10000 10160

13000 - Eocene or Older - 13000

14000 - Mmtamorphlc Ba8ernent - 14000

Probable Paleorolc Age 14480

14883 14880 TD TO

Oligacmne or Older - 7 ? - 7 -

- 11000

- 12000

12700

Figure 18. STRATIGRAPHIC SUMMARY o f NORTON SOUND COST No. 1 W E L L

PALEOBATHYMETRY

Pleistocene 180'- 1,320'

Pliocene late 1,320'- 1,808' 2,000 middle 1,608'-2,327' early 2,327'-2,839'

Miocene 3,000

late 2,839'-3,464' early 3,464'-4,493' 4,000

Oligocene 4,493'- 9,680'

posslblm Oligocene or older marine

9,690~12.235' 1 1.000

Possible Eocene or older 2m000

12.235'-12,545' - 13.000 metamorphic

Probable Paleozoic

Figure 19. STRATIGRAPHIC SUMMARY of NORTON SOUND COST No. 2 WELL

PALEOBATHYMETRY

Pleistocene 460'-1,320'

Pliocene late 1,320'-1,846' middle 1,846'-2,228' early 2,228'-2,580'

Miocene late 2,580'-3,120' early 3,120'-3,524'

Oligocene 3,524'-10,160'

Eocene 1 1.000

10,180'- 12,700' I

Eocene or older

Probable Paleozoic 14,400'-14,889' f D 14,889'- metamorphic -

seen above 6800 f e e t i n both. C o r r e l a t i o n s a r e somewhat more d i f f i c u l t below

6800 f e e t i n t h a t t h e p redominan t l y nonrnarine s t r a t a o f t h e No, 2 w e l l must be

compared w i t h t h e predominant ly s h e l f and s l ope depos i t s o f t h e No. 1 w e l l .

With t h e excep t i on o f t h e Eocene and o l d e r sec t i on , which i s f a r t h i c k e r i n

t h e No. 2 we1 1, t ime -equ i va len t u n i t s a r e a l s o rough l y e q u i v a l e n t i n th ickness .

Sedi inentat ion r a t e s were n o t c a l c u l a t e d because o f t h e t e n t a t i v e n a t u r e o f some

o f t h e b i o s t r a t i g r a p h i c boundaries.

P l e i s t o c e n e

The f i r s t sample i n each w e l l i s P le i s t ocene i n age, a l though i t i s a lmost

c e r t a i n t h a t a t h i n Holocene s e c t i o n was penetrated. Sample q u a l i t y i s poor,

The base o f t h e P le i s tocene was p laced a t 1320 f e e t i n b o t h we l l s . M i c r o f o s s i l

assembl ages, 1 i t h o l o g y , and d e p o s i t i o n a l env i ronments a r e essenti a1 l y i d e n t i c a l . Shal low se ismic ev idence i n d i c a t e s t h a t t h e r e rnay be a sl i g h t unconformi t y

between t h e P l i ocene and t h e P le is tocene,

P l i ocene

The t o p o f t he P l i ocene i s a t 1320 f e e t i n each w e l l , t h e base a t 2639

f e e t i n t h e No. 1 w e l l and 2580 f e e t i n the No. 2 w e l l . The P l iocene was

subd iv ided i n t o e a r l y , midd le , and l a t e i n bo th w e l l s on t h e b a s i s o f s i l i c e o u s

m i c r o f o s s i 1 assemblages, b u t t h e c h a o t i c m i x t u r e of reworked and caved forrns

renders such s u b d i v i s i o n t e n t a t i v e and p r o v i s i o n a l a t best . I n genera l , t h e

l n i c r o f o s s i 1 assembl ages i n b o t h we1 1 s r e f1 e c t s i rni 1 a r pa l eoenvi ronments.

M i ocene

The t o p o f t h e Miocene i s a t 2639 f e e t i n t h e No. 1 w e l l and a t 2580 f e e t

i n t h e No. 2 w e l l . There appears t o be a m idd le Miocene h i a t u s , perhaps a

paracon fo rmi ty , p resen t i n b o t h we l l s . Th i s " s u r f a c e " i s d e f i n e d i n b o t h w e l l s

by t h e t o p of t h e e a r l y Miocene, 3464 f e e t i n t h e No. 1 w e l l , and 3120 f e e t i n

t h e No, 2 w e l l . The base o f t h e e a r l y Miocene i s a t 4493 f e e t i n t h e No, 1

w e l l and a t 3524 f e e t i n t h e No. 2 w e l l . M i c r o f o s s i l assemblages and 1 i t h o l o g i e s

a r e q u i t e s i m i l a r i n b o t h w e l l s , though t h e r e i s some ev idence t h a t d e p o s i t i o n

was a t s h a l l o w e r depths i n t h e No, 2 we l l .

01 i gocene

S t r a t a ass igned t o t h e Ol igocene epoch account f o r r ough l y h a l f of t h e

sed imentary s e c t i o n pene t ra ted by t h e we1 l s , 5197 f e e t i n t h e No. 1 w e l l ,

6644 f e e t i n t h e No. 2 we1 1. I n t h e No. 1 we1 1 t h e 01 igocene s e c t i o n (4493-

9690 f e e t ) i s rep resen ted almost e n t i r e l y by mar ine d e p o s i t i o n , much o f i t

o u t e r s h e l f and upper s lope. Ry way o f c o n t r a s t , i n t h e Ol igocene s e c t i o n o f

t h e No. 2 w e l l (3524-10,160 f e e t ) , w e l l ove r h a l f o f t h e sediments a r e c o a l -

b e a r i n g and were depos i t ed under c o n t i n e n t a l t o t r a n s i t i o n a l c o n d i t i o n s .

There i s a sma l l , bu t pronounced, c o n t i n e n t a l t o t r a n s i t i o n a l env i ronment

p resen t near t h e t o p o f t he Ol igocene s e c t i o n i n t h e No, 1 w e l l (4740-4980

f e e t ) t h a t i s c o r r e l a t i v e w i t h t h e coa l beds seen i n t h e No. 2 w e l l a t 3524 t o

@ 3930 f e e t and a t 4250 t o 4440 f e e t . The mar ine t r a n s g r e s s i v e s e c t i o n f r om 5360

t o 6770 f e e t i n t h e No. 2 we l l i s c e r t a i n l y i n p a r t c o r r e l a t i v e w i t h t h e upper

ba thya l env i ronments seen below 81 30 f e e t i n t h e No. 1 we1 1.

Eocene

D e f i n i t e l a t e t o m idd le Eocene s t r a t a a r e p resen t f rom 10,160 t o 12,700

f e e t i n t h e No. 2 w e l l . A l though no Eocene f o s s i l s were found i n t h e No. 1

w e l l , i t i s p o s s i b l e t h a t t h e p rob lema t i c Ol igocene o r o l d e r s e c t i o n (9,690 t o

12,235 f e e t ) i s i n p a r t c o r r e l a t i v e w i t h t h e Eocene s e c t i o n i n t h e No. 2 w e l l .

Eocene o r 01 d e r

I n b o t h we1 1 s a coa l - bea r i ng sec t i o n unconformably over1 i e s t h e r e g i ona l

e a r l y T e r t i a r y t o l a t e I"lesozoic e r o s i o n a l sur face. Th i s c o n t i n e n t a l sec t i on ,

310 f e e t t h i c k i n t h e No. 1 w e l l and 1760 f e e t t h i c k i n t h e No. 2 w e l l , i s

t r u n c a t e d by an uncon fo rm i t y a t 12,235 f e e t i n t h e No. 1 w e l l and a t 12,703

f e e t i n t h e No. 2 w e l l . Because b o t h d e p o s i t i o n and e r o s i o n t o o k p l a c e i n two

subbasins separa ted by a p o s i t i v e t e c t o n i c element, t h i s unconfor rn i ty i s n o t

c h a r a c t e r i z e d by a con t inuous se ismic r e f 1 ec to r . Never the less, i t i s reasor iable

t o assume t h a t t h e unconforrni t i e s a r e approx imate ly coeval . L i kewi se, on t h e

b a s i s of 1 i tho logy , d e p o s i t i o n a l env i ronment, s t r a t i g r a p h i c p o s i t i o n , and t h e

s i m i l a r p r e s e r v a t i o n a l s t a t e o f t h e pa lyno~norphs, i t seems h i g h l y l i k e l y t h a t

t h e Eocene o r o l d e r sec t i ons i n t h e two w e l l s a r e i n p a r t c o r r e l a t i v e .

Basement Compl ex ( P o s s i b l e Pal eozo i c )

Both we1 1 s pene t ra ted rnetasedimentary sec t i ons be1 ow t h e r e g i o n a l unconfor ln i t y

t h a t marks acous t i c basement. The 2135 - foo t - t h i ck sequence of c a t a c l a s t i c

rocks i n t h e No. 1 w e l l appears q u i t e s i m i l a r t o slate o f Precambrian t o

Pa leozo ic age descr ibed f rom t h e York Mountains o f t h e Seward Peninsula; t h e

429 f e e t o f q u a r t z i t e , p h y l l i t e , and marb le i d e n t i f i e d i n t h e No. 2 well

appears t o be q u i t e s i m i l a r t o metamorphic rocks o f p robab le Pa leozo ic age

desc r i bed from t h e c e n t r a l and eas te rn p a r t s o f t h e Seward Peninsula. I t i s

n o t p r e s e n t l y p o s s i b l e t o more c l o s e l y r e l a t e t h e metamorphic sec t i ons o f the

two w e l l s on t h e b a s i s of e i t h e r age o r genesis.

LITHOLOGY

AND

GEOPHYSICAL LOG INTERPRETATION

by J . G , Bolm

Exa~ni n a t i o n o f c u t t i n g s , conven t i ona l and s i d e w a l l cores, and geophys ica l

( e l e c t r i c ) l o g s f r om t h e w e l l p rov i ded i n f o r m a t i o n on 1 i t h o l o g i e s , ages,

d e p o s i t i o n a l environments, r e s e r v o i r c h a r a c t e r i s t i c s , and hydrocarbon source-rock

p o t e n t i a l s o f t h e s t r a t a penet ra ted. L i t h o l o g y and r e s e r v o i r c h a r a c t e r i s t i c s

d iscussed i n t h i s s e c t i o n a re based p r i m a r i l y on c o n s u l t a n t s ' r e p o r t s , e s p e c i a l l y

t h e p e t r o l o g i c r e p o r t by AGAT Consu l tan ts , Inc. , and t h e examina t ion o f geophys ica l

1 ogs. The gamma-ray, spontaneous p o t e n t i a l ( S P ) , deep r e s i s t i v i t y , d e n s i t y , and

son ic l o g s a re p resen ted w i t h o t h e r geo log i ca l and geophys ica l we1 1 da ta i n

P l a t e 1. Framework c l a s t composi t ions of sandstone samples f rom conven t iona l

co res a r e p resen ted i n F i g u r e 20.

0-1 180 f e e t

Geophysical 1 oggi ng o f t h e we1 1 began a t 11 80 f e e t , and recovery of c u t t i ngs

was poo r above 1230 f e e t . The few c u t t i n g s recovered f r o ~ n t h i s uppermost p a r t

of t h e w e l l a r e p redominan t l y ve ry f i n e t o coarse sand-s ize g r a i n s o f q u a r t z ,

hornblende, ep ido te , muscov i te , and va r i ous v o l c a n i c , metamorphic, and s i l t s t o n e

fragments. A few s i l t y o f sandstones were cemented w i t h i r o n ox ide. Fo ram in i f e ra

and o t h e r mar ine f o s s i l s a r e p resen t i n these samples.

11 80-3535 f e e t

The i n t e r v a l f r o m 1180 t o 3535 f e e t i s c h a r a c t e r i z e d by diatomaceous mudstone,

s i l t s t o n e , and muddy sandstone, Sand c l a s t s range f rom very f i n e t o coarse and

c o n s i s t p r i m a r i l y o f qua r t z , f e l dspa r , muscovi t e , and rock fragments. Qua r t z

c l a s t s a r e subangular t o subrounded, The sand g r a i n s a r e g e n e r a l l y w e l l so r ted ,

bu t t he muddy sandstones themselves a r e p o o r l y sor ted. Rocks i n t h i s i n t e r v a l

a r e l o c a l l y ca lcareous and c o n t a i n minor ep ido te , p y r i t e , g l aucon i t e , s h e l l

deb r i s , and Foramin i fe ra . P o r o s i t i e s o f 19 s i d e w a l l - c o r e samples f rom t h i s

i n t e r v a l range f rom 28.5 t o 53.6 percent . Perrneabil i t i e s f o r these same samples

range f rom 1.06 t o 58 mD w i t h most va lues under 10 mD.

The gamma-ray and SP l o g s suggest t h e presence of severa l 25- t o 100- foot -

t h i c k , re1 a t i v e l y coarse-g ra ined beds assoc ia ted w i t h t h i n n e r , f i n e r - g r a i ned

i n t e r b e d s i n t h e upper p a r t o f t h i s i n t e r v a l . Below 1685 f e e t (gamma-ray) and

1840 f e e t (SP) t h e log curves do n o t d e f i n e i n d i v i d u a l Seds. R e s i s t i v i t i e s a r e

low w i t h a d i f f e r e n c e o f about 1 ohm-rn comrnon between t h e deepest and sha l l owes t

measured va lues above 2200 f e e t , Below 2200 f e e t t h e r e i s l i t t l e d i f f e r e n c e

between t h e deepest and sha l lowes t r e s i s t i v i t y values.

The d e n s i t y and son i c l ogs d i s p l a y numerous e r r a t i c k i c k s due t o wash ou t s

i n t h i s i n t e r v a l . Where c a v i n g was n o t a problem, t h e d e n s i t y l o g i n d i c a t e s

average d e n s i t i e s o f about 1.75 g/cm3 f o r these rocks, and t h e son ic l o g shows

a genera l decrease i n i n t e r v a l t r a n s i t t ime f r o m 205 t o 145 p s / f e e t downward th rough

t h e i n t e r v a l ,

The presence of abundant mar ine f o s s i l m a t e r i a l and g l a u c o n i t ~ i n t h e rocks

o f t h i s i n t e r v a l i n d i c a t e s d e p o s i t i o n i n a mar ine s h e l f environment.

3535-4570 f e e t

The i n t e r v a l f rom 3535 t o 4570 f e e t i s c h a r a c t e r i z e d by in te rbedded coa l and

p o o r l y i n d u r a t e d mudstone, s i l t s t o n e , and sandstone. The mudstone and s i l t s t o n e * are commonly micaceous and c o n t a i n s c a t t e r e d sand g ra ins . The sandstone i s

comprised o f qua r t z , f e l d s p a r , and 1 esser rock fragments and 1 oca l l y i s ini caceous.

Q u a r t z c l a s t s a re subangular t o rounded. The sandstone ranges f rom very f i n e t o

very coarse g ra ined and i s moderate ly t o we1 1 sor ted. The sandstone i s l o c a l l y

muddy o r s i l t y . P y r i t e i s common i n t h i s i n t e r v a l ,

P o r o s i t i e s of 9 s i d e w a l l cores o f sandstones f rom t h i s i n t e r v a l range f r o m

26.1 t o 33 .7 percent . Measured pe r~neab i l i t y ranges f rom 9.89 t o 976 mD. Most

o f t h e sandstone permeabi 1 i t y va l ues, especi a1 l y t h e h i g h e r ones, a r e p robab ly

t o o l a r g e due t o rock f a b r i c d i s r u p t i o n i n t h e c o r i n g process.

The SP and gamma-ray l o g s d i s p l a y b l o c k y c h a r a c t e r s c o n s i s t e n t w i t h i n t e r -

bedded f i n e r - and c o a r s e r - g r a i ned rocks. Numerous sharp k i c k s t o 1 ower va l ues

on t h e garnma-ray l o g t h a t cor respond w i t h h i g h r e s i s t i v i t i e s and low d e n s i t i e s

and son i c v e l o c i t i e s on o t h e r l o g s a r e i n t e r p r e t e d t o r ep resen t coa l beds. The

SP and gamma-ray l o g s show a t o t a l o f 260 f e e t o f sandstone i n 5- t:, 50 - foo t

beds i n t h i s i n t e r v a l , The r e s i s t i v i t y cu r ve d i s p l a y s a l e s s pronounced b l o c k y

c h a r a c t e r t han t h e SP and gamma-ray curves. Separa t ion of about 1 ohm-m i s

common between t h e sha l l ow and deep r e s i s t i v i t y cu rves i n coa rse r -g ra i ned beds.

The sha l l ow and deep r e s i s t i v i t y va lues a r e commonly t h e same f o r f i n e r - g r a i n e d

beds. Sharp k i c k s t o h i g h e r r e s i s t i v i t y va lues a r e p resen t where t h e gamma-ray

l o g i n d i c a t e s coa l beds. The d e n s i t y l o g i n d i c a t e s d e n s i t i e s r ang ing from 2 t o

2.25 g/crn3, b u t d e n s i t i e s as l o w as 1.3 inark t h e l o c a t i o n s o f coa l beds. The

d e n s i t y l o g i n d i c a t e s p o r o s i t i e s r ang ing f r om 28 t o 39 pe rcen t f o r sandstone i n

t h i s i n t e r v a l . The son i c l o g shows i n t e r v a l t r a n s i t t imes g e n e r a l l y r ang ing

f rom 130 t o 115 rns/foot. The h i g h e r i n t e r v a l t r a n s i t t imes a r e assoc ia ted w i t h

coa l beds, a l t hough these coa l beds a r e n o t as w e l l d e f i n e d on t h e son i c l o g as

on t h e garnma-ray and d e n s i t y 1 ogs. The son i c l o g , when c o r r e c t e d f o r under-

compaction, i n d i c a t e s sandstone p o r o s i t i e s r ang ing f r om 29 t o 34 percen t .

A t l e a s t p a r t o f t h i s coa l -bea r i ng i n t e r v a l was depos i ted i n a f l u v i a l o r

d e l t a i c environment , b u t t h e recovery of mar ine f o s s i 1 s (see Pal eon to logy and

B i o s t r a t i g r a p h y s e c t i o n o f t h i s r e p o r t ) ' i n d i c a t e s t h a t some o f t h e rocks were

depos i t ed i n a nearshore mar ine env i ronment.

4570-6000 f e e t

The i n t e r v a l f rom 4570 t o 6000 f e e t i s c h a r a c t e r i z e d by i n te rbedded mudstone,

s i l t s t o n e , and sandstone w i t h minor amounts o f coa l , Convent ional cores 1 and 2

a r e f r o m t h i s i n t e r v a l and a r e descr ibed i n f i g u r e s 21 and 22. The mudstone

general ly con ta ins ve ry f i n e sand, and sandstone i s general l y muddy o r s i l t y .

Sand c l a s t s range f rom very f i n e t o f i n e g r a i n and c o n s i s t o f b o t h monocrys ta l l i n e

a and p o l y c r y s t a l l i n e qua r t z , p l ag ioc lase , and potass ium f e l d s p a r i n g e n e r a l l y

subequal amounts, as w e l l as v o l c a n i c , metamorphic, and sedimentary rock fragments,

M i no r g laucon i t e and f rarnboidal p y r i t e a r e p resen t 1 oca l 1y i n t h e sandstone.

The sandstone con ta ins s c a t t e r e d b i v a l v e fragments and i n conven t iona l cores i s

seen t o be lamina ted o r c ross- lamina ted and burrowed.

Soine d u c t i l e g r a i n s have been deforrned i n t h e sandstone o f t h i s i n t e r v a l ,

and au th igen i c c a l c i t e o r , l e s s commonly, s i d e r i t e cement i s p resen t i n i n t e r -

g ranu la r spaces t h a t a re n o t f i l l e d w i t h ma t r i x . Measured p o r o s i t i e s f rom 13

s i d e w a l l and convent iona l c o r e samples of sandstone range f r o m 1.5 t o 27.9

percent . P e r m e a b i l i t i e s range f r om 0.15 t o 173 mD. The l owes t va lues i n bo th

c a t e g o r i e s a r e f r o l ~ l ca l c i te-cemented rocks, and most samples have p o r o s i t i e s i n

t h e 20-percent range and p e r m e a b i l i t i e s o f a t l e a s t 1 mD. The h i g h e s t p e r m e a b i l i t y

Sandstone - 01 i ~ e - ~ r a ~ ( 5 ~ 4 / 11, very fine grained, muddy, ripple cross-laminated, burrowed.

Explanation

I

25 .4

25.6

q- burrow 0 -b iva lve

@-gastropod

A-flame structure p -pyrite

Y -cross- bedding -

Figure 21. Description of conventional core I, Norton Sound COST No. 2 wel l (Porosity and permeability data from Core Laboratories, Inc.: geochemical data f r o m Core Laboratories. Inc.)

4 0.07

7 3 ( F )

1 .60

0.42

I

0.31

T . O . C . (%)

Permeability (Millidarcies)

P o r o s i t y (Percent)

O L I G O C E N E

T E R T I A R Y

f rom an u n f r a c t u r e d conven t i ona l c o r e sample i s 5.88 mD. Many o f t h e h i g h e r

va lues from s i d e w a l l co res p robab ly r e s u l t e d from f a b r i c d i s r u p t i o n consequent

t o s h o o t i n g t h e cores.

Coal i s p resen t i n smal l b u t s i g n i f i c a n t amounts i n some of t h e c u t t i n g s

sampled f rom t h i s i n t e r v a l . Th is coa l i s i n t e r p r e t e d as r e p r e s e n t i n g t h i n beds

s c a t t e r e d th rough t h e i n t e r v a l .

The SP cu r ve i s r e l a t i v e l y f l a t w i t h some b l o c k y excu rs i ons t h a t a r e i n t e r p r e t e d

t o be sandstone beds. There i s a 200- foot t o t a l t h i c k n e s s o f sandstone i n beds

5 t o 65 f e e t t h i c k de f i ned by the SP l o g i n t h i s i n t e r v a l , b u t t h e presence of

sandstone i n conven t i ona l and s i d e w a l l co res where t h e r e i s no such SP d e f l e c t i o n

i n d i c a t e s t h a t t h e i n t e r v a l con ta i ns more sandstone than t h e SP l o g suggests.

The gamma-ray cu r ve i s f l a t and l a c k s i n t e r p r e t a b l e c h a r a c t e r ove r t h i s i n t e r v a l .

The r e s i s t i v i t y l o g i s b l ocky , and t h e r e i s g e n e r a l l y no s e p a r a t i o n b e t w e n

sha l l ow and deep r e s i s t i v i t y va lues except i n a 6 5 - f o o t - t h i c k sandstone bed

(5710-5775 f e e t ) where t h e r e i s a s e p a r a t i o n of about 1.5 ohm-rn. The d e n s i t y

1 og i n d i c a t e s d e n s i t i e s o f from 2.1 t o 2.25 g/crn3. D e n s i t y - d e r i ved sandstone

p o r o s i t i e s range f rom 25 t o 32 percent . I n t e r v a l t r a n s i t t imes as recorded on

t h e son i c l o g a r e g e n e r a l l y between 150 and 105 ms / f oo t , and t h e son i c l o g , when

c o r r e c t e d f o r undercornpaction, i n d i c a t e s sandstone p o r o s i t i e s r a n g i n g f r om 26 t o

30 percen t .

a The presence o f mar ine f o s s i l s , g l aucon i t e , and t h i n coa l beds i n t h i s

i n t e r v a l i n d i c a t e s d e p o s i t i o n i n a m i x t u r e o f marine, f l u v i a l , o r d e l t a i c env i r on -

ments.

6000-8425 f e e t

The i n t e r v a l f rom 6000 t o 8425 f e e t i s c h a r a c t e r i z e d by i n t e rbedded mudstone,

s i l t s t o n e , sandstone, and coa l . Convent iona l co res 3 and 4 a r e f rom t h i s i n t e r v a l

and a r e desc r i bed i n f i g u r e s 23 and 24. The mudstone and s i l t s t o n e a r e g e n e r a l l y

1 ami nated, carbonaceous, and a re 1 oca l l y sandy, The sandstones a re genera l l y

p o o r l y s o r t e d w i t h ve ry f i n e - t o medium-size c l a s t s o f qua r t z , f e l d s p a r , and

rock f ragments i n a d e t r i t a l ma t r i x . Both monocrysta l l i n e and po1 ,yc rys ta l l i n e

q u a r t z c l a s t s a r e p resen t , and potass ium f e l d s p a r and p l a g i o c l a s e a r e p resen t i n

subequal amounts. Rock fragments a r e a lmost e n t i r e l y sch i s t ose , b u t a few v o l c a n i c

and sedimentary rock f ragments a r e a l s o p resen t . The sandstone i s commonly

l am ina ted o r c ross -1 ami nated, and shal e p a r t i n g s and graded bedding were observed

i n t h e conven t i ona l co res frorn t h i s i n t e r v a l . Burrows a r e p resen t l o c a l l y i n

b o t h sandstone and mudstone. The sandstone has been a f f e c t e d by d u c t i l e g r a i n

de fo rmat ion , and where t h e r e i s no m a t r i x , a u t h i g e n i c k a o l i n i t e , s i d e r i t e , a n k e r i t e ,

o r s y n t a x i a l q u a r t z a r e p resen t as cements. P y r i t e f ramboids a r e a l s o common,

b u t p y r i t e cement was n o t observed. P o r o s i t y ranges f rom 10.1 t o 31.2 pe rcen t

and p e r m e a b i l i t y f rom 0.22 t o 543 mD i n 37 s i d e w a l l and conven t i ona l c o r e samples

o f sandstone f r om t h i s i n t e r v a l . Most p e r m e a b i l i t y va lues f rom conven t i ona l

c o r e samples a r e l e s s than 10 mD. Three samples f rom c o r e 3 a r e b e t t e r

s o r t e d than t h e o t h e r samples and have p e r m e a b i l i t i e s o f 40, 183, and 543 mD.

L.----,,, - - - - - - - - l . . . . . . . . . . Mudstone - grayish-black (~2)~ very f ine -f t- --- - - - - - - - - - ........... - - - - - - - - sandy at top; black(~l), silty at

base; contains scattered carbonaceous debris; weakly laminated.

Coal

Mudstone - carbonaceous.

Sandstone - brownish-olive-black ( 5 ~ 2 /I), very fine grained, silty at top; medium dark gray ( ~ 4 ) ~ very fine to fine grained at base; contains carbonaceous partings and stringers; laminated with some massive areas above 7027 feet and ripple cross- lamination or burrows in places.

Explanation

q - b u r r o w 0 - b i v a tve

m-gastropod

A-flame structure p -pyrite Y-cross-bedding -

n r d a- w Figure 23. Description of conventional core 3, Norton Sound COST No. 2 o m , 5 : 0

0

well (Porosity Permeability, and geochemical data from Core Laboratories, 4 0 r & m n m r c o . OX

ID P. w. Dl w Inc.) s r t L V

f l U P . - w * F x

0 P. - P. rt (D 'C in

Sands tone - g r a y i s h - b l a c k ( ~ 2 ) , very f i n e g r a i n e d , s i l t y n e a r t o p , t h i n l y l a m i n a t e d w i t h c o a l y l e n s e s and ca rbonaceous s t r i n g e r s , burrowed i n p l a c e s ; a s m a l l , open , a symmet r i ca l f o l d w i t h a x i a l p l a n e s h e a r i s l o c a t e d n e a r t h e b a s e o f t h i s b e d .

Sands tone and mudstone - s a n d s t o n e , l i g h t - o l i v e - g r a y ( 5 ~ 5/21 f i n e - t o medium-grained, g r a d e s upward t o mudstone, b l a c k ( ~ l ) , m o t t l e d , burrowed.

Sands tone and mudstone - s a n d s t o n e , g r a y i s h - b l a c k ( ~ 2 ) , v e r y f i n e g r a i n e d , g r a d e s upward t o mudstone, b i a c k ( ~ 1 ) .

Coal

Sands tone and mudstone - s a n d s t o n e , brownish-gray (5 YR 4/1), v e r y f i n e g r a i n e d , burrowed, c u t by q u a r t z v e i n s , g r a d e s upward t o mudstone, b l a c k ( ~ 1 ) .

Sands tone and mudstone - two g raded beds .

Sands tone - med iurn-ol i v e - g r a y ( 5 ~ 5/1), v e r y f i n e g r a i n e d , l a m i n a t e d and c r o s s - l a m i n a t e d w i t h ca rbonaceous s h a l e p a r t i n g s .

Sands tone and mudstone - f i v e g raded beds .

Mudstone - g r a y i s h - b l a c k (~2), c a r b o n a c e o u s , l a m i n a t e d .

Coal

Mudstone - g r a y i s h - b l a c k ( ~ 2 ) , ca rbonaceous , .;; 2 l a m i n a t e d . (D 0 rl r d o .

n

Coal o m ID P. P ~ D P. pl 0 u x

s n a u S i l t s t o n e - gray i s h - b l a c k (NZ), v e r y r + ' ~ sue- -

w 0-

fin:-. sandy, c a r b o n a c e o u s , O F v k. rr weak1 y l amina ted . ID V

M w

Figure 24. Description of conventional core 4, Norton Sound COST No. 2 well. fDarnei+t, r , a v m a a h i f i t s , . -m~nnh~- ia- l A - 4 - 8 - - - - - - - - L - - - * - - : - - a - - %

a The h i g h p e r m e a b i l t i e s t h a t c h a r a c t e r i z e most o f t h e s i d e w a l l c o r e samples from

t h i s i n t e r v a l p robab l y r e s u l t e d a t l e a s t i n p a r t f rom f a b r i c d i s r u p t i o n a t t endan t

on sampl i ng.

The SP cu r ve has a b l o c k y c h a r a c t e r c o n s i s t e n t w i t h i n t e rbedded f i n e r - and

coa rse r -g ra i ned l i t h o l o g i e s . A t o t a l o f 560 f e e t of sandstone i n 5- t o 50 - f oo t

beds can be recogn ized on t h e SP l og . The gamma-ray cu r ve i s r a t h e r f l a t i n t h e

upper p a r t o f t h i s i n t e r v a l b u t becomes q u i t e e r r a t i c be low 6700 feet . The

gamma-ray l o g i s no t e a s i l y i n t e r p r e t e d th rough t h i s i n t e r v a l , w i t h t h e excep t i on

o f k i c k s t o l o w va lues t h a t p robab l y cor respond t o coa l beds. The r e s i s t i v i t y

i s s i m i l a r i n t h i s i n t e r v a l t o t h e i n t e r v a l above b u t has numerous sharp k i c k s

t o h i g h e r va lues i n d i c a t i v e of coa l beds. There i s a1 so a gradual i n c r e a s e i n

r e s i s t i v i t y downward th rough t h i s i n t e r v a l , and sepa ra t i ons between s h a l l ow and

deep r e s i s t i v i t y va lues of 2 t o 4 ohm-m a r e common f o r sandstone beds. The

d e n s i t y l o g i n d i c a t e s a gradual i n c rease o f d e n s i t y w i t h d e n s i t i e s g e n e r a l l y

f rom 2.2 t o 2.5 g/cm3. Numerous sharp k i c k s t o 1 ower va lues c o r r e l a t e w i t h

coa l beds. The d e n s i t y l o g i n d i c a t e s p o r o s i t i e s o f from 12 t o 35 pe rcen t f o r

sandstone i n t h i s i n t e r v a l . The son ic l o g shows a genera l decrease i n i n t e r v a l

t r a n s i t t i m e th rough t h i s i n t e r v a l , w i t h va lues g e n e r a l l y between 110 and 85

us / f oo t . K icks t o l owe r i n t e r v a l t r a n s i t t imes c o r r e l a t e w i t h coa l beds. The

son i c l o g , when c o r r e c t e d f o r undercompact ion, i n d i c a t e s p o r o s i t i e s o f f rom 9 t o

29 percen t f o r sandstone i n t h i s i n t e r v a l .

a Mar ine f o s s i l s have been recovered from t h i s i n t e r v a l ( see Pa leon to logy and

B i o s t r a t i g r a p h y s e c t i o n of t h i s r e p o r t ) , b u t t he a s s o c i a t i o n of coa l w i t h

sandstone and mudstone seen i n co res and suggested by geophys ica l l o g i n t e r p r e t a t i o n

i n d i c a t e s d e p o s i t i o n i n f l u v i a l o r d e l t a i c environment. The i n t e r v a l as a whole

was p robab l y depos i t ed i n a t r a n s i t i o n a l environment where mar ine and nonmarine

c o n d i t i o n s a l t e r n a t e d . Only a few t h i n coa l beds a r e p resen t i n t h e upper p a r t

o f t h e i n t e r v a l ; i t i s l i k e l y t h a t more of t h e rock i n t h e upper p a r t o f t h e

i n t e r v a l was depos i t ed i n a mar ine environment t han was t h e case i n t h e more

coa l y , l owe r p a r t o f t h e sec t ion .

8425-9230 f e e t

The i n t e r v a l from 8425 t o 9230 f e e t c o n s i s t s o f s i l t s t o n e and mudstone w i t h

0 minor sandstone. Convent iona l c o r e 5 i s from t h i s i n t e r v a l and i s desc r i bed i n

f i g u r e 25. L i t h o l o g i e s a r e s i m i l a r t o t hose of the i n t e r v a l above except t h a t

v o l c a n i c r ock f ragments predominate among t h e li t h i c sand c l a s t s . Two sidewall

c o r e sandstone samples had 23.4 percen t p o r o s i t y and p e r m e a b i l i t i e s of 1 6 and 40

mD. Ten sandstone samples from c o r e 5 had p o r o s i t i e s froin 8.5 t o 17.5 pe rcen t

and p e r m e a b i l i t i e s f r om 0.07 t o 4.28 mD. The h i g h e r p o r o s i t i e s o f t h e s i d e w a l l

c o r e samples may be r e a l , b u t t h e h i g h e r p e r m e a b i l i t i e s a r e p robab l y due t o

f a b r i c d i s r u p t i o n i n sampl ing,

A -4 ri -Y E d m z m m 3 U 4 0 h Car m h u u b r l + m M P 3 e ~m o k L l a J L , m m u r p

P > c a O I d

3 -b" ' " f . r l a r a r n 'tl c +

a n d I * ~ m m u

k r n C I M O 0

M U O J a J L I m

0.d b 3 J A W 0 E V)

I I l u l U . h a & 0 a' a' a ' b b L i 3 r n u m m u o m .,""? & "

* E m 3 U I a J z a ' 9 m

T.O.C. (%)

OI

rp vl

u

a' c o m

Permeability (Millidarcies:

c a d C 0 U . d X U

c u a r r p r l r n O m E b r i r d u u ~ m u r n d * u

@J a' 0 0' C r n e c r i U

0.d 3 a - U ' u * r i urr] U L u aJ'C1 h a

C u c k u b r p m m w m o

* . 5 u -d

~ + t ~ E m m m u Q a UHZZri 4

Porosity (Pe r cen t )

- OLIQOCENE

b,

T E R T I A R Y

The SP cu rve th rough t h i s i n t e r v a l i s smooth and s t r a i g h t w i t h a few g e n t l e

undu la t ions . The lower va lue undu la t i ons appear t o mark t h e l o c a t i o n s o f t h e

sand ie r p a r t s o f t h e s t r a t i g r a p h i c sec t ion . The gamma-ray l o g curve g e n e r a l l y

f o l l o w s t h e SP l o g curve, b u t i s jagged r a t h e r than smooth and d i s p l a y s severa l

sharp k i c k s t h a t c o r r e l a t e w i t h coa l beds. The r e s i s t i v i t y cu rve i s smooth and

g e n t l y u n d u l a t i n g except where severa l sharp k i c k s i n d i c a t e coa l beds. There

i s 1 i t t l e o r no d i f f e r e n c e between t h e s h a l l owest and deepest measured r e s i s t i v i t y

va lues i n t h i s i n t e r v a l . The d e n s i t y and son ic l o g curves a r e re1 a t i v e l y smooth

w i t h some sharp k i c k s i n d i c a t i v e o f coa l beds and ha rd s t reaks . The d e n s i t y l o g

i n d i c a t e s d e n s i t i e s g e n e r a l l y i n t h e range f rom 1.9 t o 2 g/cm3. The son i c l o g

i n d i c a t e s general i n t e r v a l t r a n s i t t imes o f from 85 t o 90 p s / f o o t .

T h i s i n t e r v a l con ta ins mar ine f o s s i l s (see Pal eon to logy and B i o s t r a t i g r a p h y * s e c t i o n of t h i s r e p o r t ) . There i s l e s s sandstone and coa l than t h e i n t e r v a l

above, and d e p o s i t i o n was p robab ly l a r g e l y i n a mar ine environment c h a r a c t e r i z e d

by s h i f t s t o f l u v i a l o r d e l t a i c cond i t i ons .

9230-1 1,958 f e e t

The i n t e r v a l f rom 9230 t o 11,958 f e e t i s c h a r a c t e r i z e d by in te rbedded

s i l t s t o n e , sandstone, mudstone, and shale. Convent ional cores 6, 7 , and 8 a r e

f rom t h i s i n t e r v a l and a r e descr ibed i n F igures 26, 27, and 28. The mudstone i s

comrnmonly lamina ted o r i n t e r l a m i n a t e d w i t h s i l t s t o n e , and some i s sandy o r

micaceous. The sandstone i s composed of ve ry f i n e qua r t z , f e l d s p a r , and 1 i t h i c

c l a s t s i n a d e t r i t a l ma t r i x . Both monocrysta l l i n e and p o l y c r y s t a l l i n e q u a r t z

c l a s t s a r e present . Rock fragments a re p redominan t l y v o l c a n i c , b u t t h e r e a r e

s i g n i f i c a n t metamorphic and sedimentary c o n t r i b u t i o n s i n samples f r o i n c o r e 6 i n

t h e upper p a r t o f t h e i n t e r v a l , Sch is tose metamorphic rock fragments predominate

t h e l i t h i c f r a c t i o n i n t h e two deeper cores. The f e l d s p a r i s p redominan t l y

p l ag ioc lase . Local 1 arnination, cross-1 aminat ion, burrows, and s o f t sediment

s t r u c t u r e s were observed i n t h e convent iona l cores.

A combinat ion o f d u c t i l e g r a i n de fo rmat ion and t h e presence o f d e t r i t a l

m a t r i x and a u t h i genic cements a f f e c t s p o r o s i t y and permeahi 1 i t y o f sandstones i n

t h i s i n t e r v a l . The a u t h i g e n i c cements i n c l u d e s i d e r i t e , p y r i t e , qua r t z , c a l c i t e ,

and k a o l i n i t e . P o r o s i t i e s o f 10 sandstone samples range from 2.9 t o 25.3 percen t ,

and p e r r n e a b i l i t i e s range f rom 0.07 t o 147 mD. A l l p o r o s i t y va luss above 5.9

percen t a ~ d p e r m e a b i l i t y va lues above 2.63 mD a r e f rom s i d e w a l l cores.

The SP cu rve i s smooth th rough t h i s i n t e r v a l . Above 10,450 f e e t i t i s

s t r a i g h t , and below t h a t depth i t undu la tes gen t l y . The gamma-ray l o g i s jagged

and does n o t c l e a r l y de f i ne any bedded u n i t s . The r e s i s t i v i t y curves a r e moderate ly

"

T E R T I A R Y

O L l Q O C E N E or O L D E R

u h

00 m r l Ln N N 0 0 d 4

Lr r- m Lr

0 0

4 r- u m

rl 1

ul e-4 m m

r( o d

m e 5 a u

Ro (%)

T . O . C . (%)

P e r r n e a b i l i t y ( M i l l i d a r c i e s

P o r o s i t y (Percent )

. - I P n z P w U aJ u C w U - .rl C 1 - aJ m aJ c m a r u . - m aJ C c 4~ - 0 ar b r c w u - c c 3 - 0

h U L1 w 5 - a m m u . d O E @ J h .d o a r o h u E L I G -0 E U [ 3 + P v l

r y ) ~ - ~ r l - ' D m M CU ( O m -94 u m LO *.ri a -0-0 I 4 ~ h a ~ a - 1 ~ s c 3 m 4 U P I r d - 7 - 1 u Q q i - O 3 C Kz N Z ~ U ~ P ~ & m a- C W E b d C aJ a - b m W . - C t: a J k d 0 W P P a.d 0 h m " , " . - 3 U A b 0 d C n . C 2 UY 0 01 0 U W U dF1 - - U r n u + 3 - 0 C C J I - 1 7 1 N G 3 U U . d c u ~ a ~ m o N C w u o ~ ~ 5 4 , r l

r : c d z . d o a m ?+ . m u c cu .d.-u > L 5-~i o a & d k E o m - ~ . k p o ~7 "0 C + d P C k L b C V )

l ~ c r l m ~ a ~ ~ : u L ~ w . ~ u I @ ~ m ~ c t l ~ 3 I ~m,-3 3 ~ k - d

rn

m m

C m

W VJ U rl 'd V]

urn U C U w k - ~ w n c w 3 rl O D N ~ J U E a U I , Z $ 0 ) 3 1

u ,.c

g u P U A C C U * h m J l . r i m a r l m z m 3 h

4'-cu * o m m h n h r i b b

~ t f r l l c r ~ f f l r r l k 4 0 ~ 4 1 ~ . - C Z b G . 2 3

r n - A m M + I L - r 4 I t o r 4

I u C u 3 m u k arc I . - b m u & . + G a c m ~ u c l m - 1 m . 4 ~ O W 3 a J r i 3 a k a J C 0 U h H C d O I U E Q U l L I

m m r l ~ k c u o s s w . v k a ~ r n - d b m u m u r r l c ~ b ~ ~ r m g . d m

bD h U P ~ ~ ~ . ~ * * - ~ W C ~ U C U ~ 1

u a 1 w - 1 - b cd m o m p C C C r r l U M U 3 U k N U

0 0 .d C k C OJ Y C U - d a d C u uu.rl 1 . d f 3 0 b u [I107 d L n a C N b 0.d

b l U h A U U aJ m u c o ~ c

o o k m o m o c u U M ~ u . d m W

[II u ri -4 V1

' a m u p U 3 r l - a w u z m ~ c LI c c w e w * r l + a , o m O B N h a a b u r n . U u Z ( d m a J u * E L:oE'd2:

m p i l 3 m o - m u m a , - * F : C u ~ w u . d a S O 3 m . 4 a m ar a ~ h x o o a u

r l b ~ a ~ m m c v l u hncd I H ~ m u m

~ m v l ~ ~ i C C Z I - 0 m C a J C Q J U a.5 m E U . I - d

,-d 3 ~ ~ n ~ C ~ E T ~ J U T ~ U ~ c r l c O N c 0.d rn a~ m o o

L I [II > M r l U V] U rl 'd Lo

c

v1 U 4 .d V1

@JU h * d - d v l O J U . d U

o o ~ a r ~ o o o c d o o ~ ~ r i u ~ b D E b Q d U u r l u L m

n U ri ,c(

V1

~ J U + w ~ Z S c E B u e u c o m 3s 3.d U r l C 113 U Y d

m U -1 .d cn

2 OJ m a m ~ C C E r u a

OLIGOCENE 0 r 1 OLDER

T.O.C. (%)


Porosity (Percent)

I TERTIARY I

Mudstone - g r a y i s h - b l a c k ( ~ 2 ) w i t h s c a t t e r e d s i l t s t o n e , medium- g r a y {N5), l aminae and t h i n i n t e r b e d s ; c o n t a i n s 1-cm p y r i t e - r i c h l a y e r a t 11902.1 and 2-cm c a l c a r a c e o u s s i l t s t o n e l a y e r a t 11903.2.

I Explanation ] q- burrow 0-bivalve

@-gastropod A-flame structure p -pyrite Y -cross-bedding -

n ' d +I

I- n n w m . &?

P- ru w rz 0-

Figure 28. Description of conventional core 8, Norton Sound COST No. 2 w e l l (Porosity, permeability, and geochemical data from Core Laboratories, Inc.)

@ smooth t o l o c a l l y b l ocky and d l s p l ay a d i f f e r e n c e o f about 2 ohin-rn colnmon between

t h e deep and sha l l ow values.

The d e n s i t y l o g curve i s q u i t e jagged i n t h e upper p a r t o f t h i s i n t e r v a l ,

where c a v i n g has produced an i r r e g u l a r ho le . Average d e n s i t y values range f r o m

2.4 t o 2.65 g/crn3, w i t h a general i nc rease downward, Below 10,650 f e e t , h o l e

c o n d i t i o n s were b e t t e r and t h e d e n s i t y l o g i s l e s s v a r i a b l e . Average d e n s i t i e s

range from 2.65 t o 2.7 g/crn3 i n t h e lower p a r t o f t he i n t e r v a l . The son i c l o g

cu rve i s jagged w i t h i n generally narrow l imits i n t h i s i n t e r v a l . Average i n t e r v a l

t r a n s i t t imes range f rom 98 t o 80 p s l f o o t .

The rocks of t h i s i n t e r v a l were. depos i ted i n a mar ine s h e l f environment.

a Sedimentat ion was r a p i d l o c a l l y , as i n d i c a t e d by t h e common s o f t sediment s t r u c t u r e s

i n c o r e 6.

11,958-1 2,378 f e e t

The i n t e r v a l from 11,958 t o 12,378 f e e t i s c h a r a c t e r i z e d by sandstone w i t h

1 esser amounts o f s i l t s t one , mudstone, conglomerate, and coa l . Convent ional co re 9

i s f r o m t h i s i n t e r v a l and i s descr ibed i n F i g u r e 29,

Sandscane - dark-01 i ~ e - ~ r a y ( 5 ~ 3 / 3 , v e r y f i n e t o f i n e g r a i n e d , s l i g h t l y c a l c a r e o u s l o c a l l y , mass ive ; small c o a l c h i p s i n t o p 2 f e e t d i p 40' ; s u b a n g u l a r t o rounded s h a l e c i p s and p e b b l e s common from 12215.5 t o 1 2 2 2 3 f e e t , t h e n c e s p a r s e t o b a s e of c o r e ; a 3-cm l a y e r with abundant g r a n u l e - s i z e , l i g h t c o l o r e d , a p h a n i t i c v o l c a n i c rock f r a g m e n t s c r o s s e s t h e c o r e a t 1 2 2 2 3 . 3 f e e t ; s i m i l a r v o l c a n i c r o c k f r a g m e n t s i n c o a r s e s a n d t o p e b b l e s i z e a p p e a r aga in a t 1 2 2 2 4 . 4 f e e t and i n c r e a s e i n abundance downward t o c o n s t i t u t e a lmos t c l a s t - s u p p o r t e d cong lomera te a t b a s e ; sand g r a d e i n c r e a s e s g r a d u a l l y t o f i n e a t b a s e of c o r e .

i

Explanation

q-burrow 0 -b iva lve

m-gastropod

A - f l a m e structure p -pyrite

Y -cross- bedding -

Figure 29. Description of conventional core 9, Norton Sound COST No. 2 we l l (Porosity, permeability, and geochemical data from Core Laborator ies , Inc.)

The sandstone i s p o o r l y so r t ed and c o n s i s t s o f ve ry f i n e t o mediuin qua r t z ,

p l a g i o c l a s e , and l i t h i c c l a s t s i n an abundant d e t r i t a l ma t r i x . Angular t o

subangul a r v o l c a n i c granules and pebbles a r e s c a t t e r e d i n t h e sandstone, and

l o c a l l y v o l c a n i c pebbles a re so abundant as t o make conglomerate. Subangular t o

rounded sha le g ranu les and pebbles a re a l s o p resen t i n t h e sandstone. Qua r t z

sand c l a s t s a re both non no crystal 1 i n e and p o l y c r y s t a l l i n e , and v o l c a n i c rock

f ragments and sha le dominate t h e li t h i c sand-gra in component. Coal i s p resen t

below 12,190 f e e t .

P o r o s i t i e s o f 8 sandstone samples f rom co re 9 range f rom 7.2 t o 12.2 percen t ,

and p e r m e a b i l i t i e s range f rom 0.02 t o 0.08 mO. P o r o s i t y and p e r m e a b i l i t y a r e

. adve rse l y a f f e c t e d i n t h e sandstone by d u c t i l e g r a i n de fo rmat ion and t h e presence

o f abundant d e t r i t a l m a t r i x and a u t h i g e n i c s i d e r i t e , p y r i t e , qua r t z , smect i t i c

@ c l a y , c h l o r i t e , and c a l c i t e cements. Ru th igen i c c a l c i t e i s more commonly p resen t

as a replacement o f v o l c a n i c rock fragments than as cement.

The SP cu rve undu la tes smoothly th rough t h i s i n t e r v a l and cannot be

mean ing fu l l y i n t e r p r e t e d . Th is i s p robab ly a r e s u l t o f l ow p e r m e a b i l i t y c o n t r a s t s

between t h e v a r i o u s 1 i t h o l o g i e s . The gamma-ray 1 og de f ines t h r e e ma jo r b l ocky

u n i t s w i t h a t o t a l t h i ckness o f 390 f ee t . Convent ional c o r e 9 i s f ro in t h e

m idd le o f t h e lowes t o f these u n i t s , and a l l t h r e e u n i t s a r e i n t e r p r e t e d t o he

sandstone and conglomerate s i m i l a r t o t h a t seen i n c o r e 9. The r e s i s t i v i t y

r e t a i n s t h e f i n e l y jagged c h a r a c t e r i t d i sp layed i n t h e i n t e r v a l above, b u t i s

more b l o c k y i n o v e r a l l aspect. Deep and sha l l ow r e s i s t i v i t y values a r e commonly

2 t o 5 ohm-m apar t . The d e n s i t y l o g curve i s g e n e r a l l y smooth th rough t h i s

i n t e r v a l except f o r l a r g e k i c k s i n areas o f caving. D e n s i t i e s range g e n e r a l l y

f rom 2.45 t o 2.65 g/cm3, and t h e d e n s i t y l o g i n d i c a t e s p o r o s i t i e s f rom 0 t o 8

pe rcen t f o r sandstone i n t h e i n t e r v a l . The son ic l o g cu rve i s jagged th rough

t h i s i n t e r v a l , b u t t h e average i n t e r v a l t r a n s i t t imes range o n l y f rom 80 t o 70

) ~ s / f o o t . P o r o s i t i e s as i n d i c a t e d by t h e son ic l o g range f rom 11 t o 18 percent .

The l a r g e s c a l e cross-bedding, poor s o r t i n g , and coarse g r a i n s i z e o f t h e

sandstone seen i n t h e co re f rom t h i s coa l -bea r i ng i n t e r v a l suggest t h a t t h e

rocks o f t h i s i n t e r v a l were depos i ted i n a b ra i ded stream channel.

12,378-1 2,700 f e e t

The i n t e r v a l f rom 12,378 t o 12,700 f e e t i s c h a r a c t e r i z e d by in te rbedded

0 s i l t s t o n e , rnudstone, sandstone, and minor amounts o f coa l . No s i d e w a l l o r

conven t iona l co res were taken f r o m t h i s i n t e r v a l , and t h e l i t h o l o g i e s a re known

or l l y f rom c u t t i n g s and t h e i n t e r p r e t a t i o n o f geophys ica l 1 ogs.

The SP cu rve con t inues through t h i s i n t e r v a l w i t h t h e same smooth, u n d u l a t i n g

c h a r a c t e r d i sp layed i n t h e i n t e r v a l above. The gamma-ray 1 og curve i s jagged

and does n o t c l e a r l y d e f i n e any bedded u n i t s . The r e s i s t i v i t y curves a r e moderate1.y

smooth w i t h a general d i f f e r e n c e o f 2 t o 5 ohm-m between deep and sha l l ow values.

A few sharp k i c k s t o lower r e s i s t i v i t i e s , accompanied by t h e l o s s o f deep and

shal low separa t ion , y i e l d a weak b l o c k y cha rac te r . D e n s i t i e s general l y range

from 2.7 t o 2.75 g/cm3 i n t h i s i n t e r v a l , The g r e a t e r v a r i a b i l i t y p resen t i n

t h e upper p a r t o f t h e i n t e r v a l appears t o be r e l a t e d t o minor caving. The son i c

l o g i s more v a r i a b l e i n t h e upper p a r t o f t h e i n t e r v a l than i n t h e lower , and

i n d i c a t e s g e n e r a l l y l o w e r i n t e r v a l t r a n s i t t imes i n t he upper p a r t than i n t h e

1 ower. An examinat ion o f t h e c u t t i n g s i n d i c a t e d t h e presence o f more sandstone

above 12,500 f e e t t han below t h a t depth, and t h e change i n son ic v e l o c i t y p robab ly

r e f l e c t s t h i s l i t h o l o g i c d i f f e r e n c e . Average i n t e r v a l t r a n s i t t i m e above 12,500

f e e t i s 8 0 p s / f o o t , and below 12,500 f e e t t h e average i n t e r v a l t r a n s i t t ime i s

87 )s / foot .

The presence o f coa l i n d i c a t e s d e p o s i t i o n i n a nonmarine environment.

12,700-1 4,460 f e e t

The i n t e r v a l f rom 12,700 t o 14,460 f e e t i s c h a r a c t e r i z e d by in te rbedded

sandstone, s i l t s t o n e , mudstone, and coa l . Convent ional co res 10 and 11 a r e f rom

t h i s i n t e r v a l and a r e descr ibed i n F igu res 30 and 31, The sandstone i s composed

o f angu la r t o subrounded, f i n e - t o coarse-g ra ined q u a r t z and l i t h i c c l a s t s i n an

abundant d e t r i t a l ma t r i x . The q u a r t z c l a s t s a r e p redominan t l y monocrysta l 1 i n e ,

and t h e l i t h i c f r a c t i o n c o n s i s t s p redominan t l y o f s c h i s t o s e metamorphic rock

fragments ( co re 11 ) o f subequal amounts of v o l c a n i c and metamorphic rock f ragments

( co re 10). The sandstone i s l o c a l l y 1 arninated o r cross-1 aminated and c o n t a i n s

abundant carbonaceous d e b r i s and p a r t i n g s . Burrows a re p resen t i n a s i l t s t o n e

bed i n co re 10. Open i n t e r g r a n u l a r space between t h e framework c l a s t s was reduced

Explanation

q- burrow 0 - b i v a l v e

@-gastropod

A-f lame structure p -pyrite Y-cross- bedding -

Siltstone - grayish-black ( ~ 2 ) laminated, some burrows; 15" apparent dip.

Mudstone - brownish-black (5 YR 2/1 ) Siltstone - grayish-black @ 2 )

laminated. Coal

Sandstone - dark-olive gray ( 5 ~ 3/1 ) fine to medium grained; contains 2-cm coal seam 3 inches above b a s e .

Siltstone - grayish-black(~2 ) laminated.

Figure 30. Description of conventional core 10, Norton Sound COST No.2 well (Porosity, permeability, and geochemical data from Core Laboratories, Inc.)

a m _ n m c r - c .

-a"* "3 .u 3 [I) hrgu.3 a r o L " 3 u r : F ' M ? a J c M - Y u N ' G J > a

-C a a,.* V1 k13 01.5 2

' w m r o m ~ ~ c o r r a m r g ? o w E r i c

m

V - m h l l l m y m m H d

. . . - - * m t i m - O - & *

O ° C o O O O 0 . . . . . . .

" m h Q m m d m c o , y \ i m - u m h m e . . . . . . . . a . . . . . . . . 4 4 4 - e ( d d N a r l * O r f L n r \ l Q

-"-* m a U 3 m r i F . . ' * - . * * ' - - - ( " - N ~ N o N ~ rrma ~ m a - h o - 0

P 1 d * - r i ri pi w 4 1 -

T.O.C. (%)

Perrneabi l i t y (Mill i d a r c i e s )

P o r o s i t y ( P e r c e n t )

by de fo rma t i on of d u c t i l e framework c l a s t s and t h e presence of d e t r i t a l m a t r i x

and a u t h i g e n i c s i d e r i t e , a n k e r i t e , s m e c t i t i c c l a y , and c h l o r i t e cements. I n 35

conven t i ona l and 7 s i d e w a l l cores o f sandstones the p o r o s i t i e s range frorn 3.8 t o

26.2 pe rcen t and p e r m e a b i l i t i e s f r om 0.02 t o 119 mD. The h i g h e s t p o r o s i t y f r om

a conven t i ona l co re i s 12.8 pe rcen t , however, and t h e h i g h e s t p e r m e a b i l i t y f rom

a conven t i ona l c o r e i s 3.47 mD.

The SP c u r v e wanders e r r a t i c a l l y and cannot be m e a n i n g f u l l y i n t e r p r e t e d ,

The gamma-ray l o g cu rve d i s p l a y s a b l o c k y c h a r a c t e r i n d i c a t i v e o f sandstone beds

t o 60 f e e t t h i c k and coa l beds t o 20 f e e t t h i c k . Wi th t h e excep t i on of many

extreme k i c k s c o r r e l a t i v e w i t h coa l beds, t h e r e s i s t i v i t y l o g cu r ve i s re1 a t i v e l y

smooth. Separa t ion o f deep and s h a l l o w r e s i s t i v i t y va lues o f 2 t o 5 ohm-m a r e

genera l except i n coa l beds. Both t h e d e n s i t y and son i c l o g curves have Inany * l a r g e k i c k s c o r r e l a t i v e w i t h coa l beds i n t h i s i n t e r v a l . Except f o r t h e extreme

va lues of such k i c k s , d e n s i t i e s g e n e r a l l y range f rom 2.5 t o 2.8 g/cm3, and

i n t e r v a l t r a n s i t t imes f r om 82 t o 7 0 p s / f o o t . D e n s i t y - d e r i v e d sandstone p o r o s i t i e s

range f rom 0 t o 1 5 percen t , and t h e son i c l o g i n d i c a t e s sandstone p o r o s i t i e s

from 7 t o 11 percent .

The a s s o c i a t i o n o f c o a l , sandstone, and rnudstone i n t h i s i n t e r v a l i n d i c a t e s

d e p o s i t i o n i n a f l u v i a l o r d e l t a i c environment. The g r e a t abundance o f coa l

th roughou t t h e i n t e r v a l makes i t u n l i k e l y t h e r e was any mar ine d e p o s i t i o n .

14,460-1 4,889 f e e t

The bottommost i n t e r v a l o f t h e w e l l , f rom 14,460 t o 14,889 f e e t , i s

c h a r a c t e r i z e d by 1 ow grade dynamothermal lnetamorphic rocks. Convent ional cores

12 and 13 a r e f rom t h i s i n t e r v a l and a r e desc r i bed i n f i g u r e s 32 and 33.

L i t h o l o g i e s p resen t i n c l u d e q u a r t z i t e , marble, s i l i c e o u s marb le , and phy l li t e ,

The q u a r t z i t e and marb le have mosaic f a b r i c s and t h e p h y l l i t e i s f o l i a t e d .

Q u a r t z i t e l a y e r s w i t h mosaic s t r u c t u r e a1 t e r n a t e w i t h s c h i s t o s e w h i t e mica l aye rs .

The q u a r t z i t e i s banded, and t h e banding has been i s o c l i n a l l y fo lded . Marb le i s

l o c a l l y f o l i a t e d i n t h e cores. The q u a r t z i t e and phy l l i t e o f c o r e 12 have measured

p o r o s i t i e s o f 0.6 t o 3.0 percen t and p e r m e a b i l i t i e s o f 0.01 t o 0.02 mD.

The SP cu rve wanders and cannot be m e a n i n g f u l l y i n t e r p r e t e d . The gamma-ray

cu rve i s jagged above 14,680 f e e t b u t r e l a t i v e l y smooth below t h i s depth.

There i s a sudden decrease i n t h e average gamma-ray va lue o f about 45 A P I u n i t s

a t 14,680 feet. These changes i n t h e c h a r a c t e r of t h e gamma-ray l o g cu rve p robab ly

r e f l e c t a change f rom q u a r t z i t e t o marble. There i s a sharp i nc rease i n r e s i s t i v i t y

a t t h e t o p o f t h i s i n t e r v a l . The r e s i s t i v i t y cu rve i s l a r g e l y o f f s c a l e below

14,640 f e e t , and t h e absence o f any general i nc rease i n r e s i s t i v i t y above t h a t

depth i n d i c a t e s t h e r e s i s t i v i t y i nc rease i s sudden. The r e s i s t i v i t y l o g i s

qu i t z jagged where i t i s on scale. The d e n s i t y and son ic l ogs a r e moderate ly

smooth. The d e n s i t y l o g i n d i c a t e s d e n s i t i e s g e n e r a l l y f rom 2.75 t o 2.8 g/crn3

above 14,680 f e e t and o f about 2.72 g/crn3 below t h a t depth. I n t e r v a l t r a n s i t

times g e n e r a l l y range f r om 60 t o 5 5 y s / f o o t above 14,680 f e e t and s t a y r i g h t a t

50 p s / f o o t below t h a t depth.

Quartzite - banded-bray ( ~ 3 ) and light- o l ive -g ray ( 5 ~ 6/1); bands d i p 22' ; abundant fractures are lined with talc.

Phyllite - light-gray ( ~ 7 ) .

Explanation

q -burrow 0 - b i v a l v e

(&gastropod

A - f l ame structure

p -pyri te

Y -cross-bedding -

Figure 32. Description o f conventional core 12, Norton Sound COST No. 2 w e l l (Porosity, permeability, and geochemical data from Core Laboratories, lnc.)

u h m .ri u m a ~ m o o m m u u u m

~ r - r n o m h ,Q a o o s o m 0 4 M W F.l f U 4 U V 1 u u t a W u l u l d 7.4 a I C d E E : 3 m .-ua,

m~ , ~ . - u - r l o E l - ~ u r i o a , ~ r o a\ 3 C O aJ h0 h

Q J Z ~ - P ~ L . ~ U W a u w d4 n L1

2

T.O.C. (%)


Porosity ( p e r c e n t )

PALEOZOIC ( 7 )

P o r o s i t y and Permeabil i t y

P o r o s i t y and permeabi 1 i t y de te rm ina t i ons f o r samples f rom s idewa l l and

convent iona l cores i n t h e w e l l a r e presented i n Table 1, S idewa l l c o r e p o r o s i t i e s

a r e g e n e r a l l y h i g h e r than nearby convent iona l c o r e p o r o s i t i e s , and t h i s d i s p a r i t y

i ncreases w i t h depth. A1 so, s i d e w a l l c o r e samples d i sp l ay h i g h e r permeabi 1 i t i es

than do conven t i ona l c o r e samples o f s i m i l a r p o r o s i t y . F i g u r e 34 p resen ts a p l o t

of average p o r o s i t y a g a i n s t dep th f o r sandstone samples f rom convent iona l cores,

F igure 35 p resen ts a p l o t o f average permeabi 1 i t y aga ins t average p o r o s i t y f o r

t h e same samples. There i s cons ide rab le s c a t t e r i n t h e data, However i t

can be seen t h a t t o have 1 nD p e r m e a b i l i t y a sandstone must have a t l e a s t 1 3

pe rcen t p o r o s i t y and t h a t a1 1 conven t iona l co re sandstone samples w i t h 13 pe rcen t

o r more p o r o s i t y a r e f rom depths sha l l owe r than 9000 f e e t . P o r o s i t y and p e r m e a b i l i t y

@ data from sandstone sarnpl es a r e a1 so presented g r a p h i c a l l y i n P l a t e 1. Because

o f i r r e g u l a r sample d i s t r i b u t i o n , p o r o s i t y and p e r m e a b i l i t y values have been

i n t e g r a t e d over a 500- foot t h i ckness and a r e represen ted by symbols t h a t show

t h e mean va lues and range f o r each such i n t e r v a l . The number o f sandstone samples

i n each i n t e r v a l i s g i v e n under t h e appl i c a b l e symbol.

Table 1. POROSITY AND PERMEABILITY Norton 2

[frorn Core Laboratories, Inc.]

Depth ( f e e t )

Porosity Permeability Lithology (Percent) (Mi 11 idarcies) Remarks

sl tst;sdy 31.2 1 .47 Sidewall s arne 33.8 15. Sidewall volcanic ash? 42.6 2.24 S i dewall same 41 .2 9.1 2 S i dewall same 44.4 9.49 Sidewall

same same ; sdy same ; sdy s arne s ame

s ame same same same s atne

50.0 - - Sidewall 46.7 21 . S i dewall 44.9 58. Si dewall 46.4 4.04 Sidewall 49.4 3.32 Sidewall

53.6 2.93 S i dewall 51 ,O 1.06 Sidewall 47.7 6.41 Sidewall 45.7 1.99 Sidewall 41.9 5.88 Sidewall

s arne 47.1 7.66 Sidewall same;shy 40.5 18. Sidewall sl tst;sdy,ash? 35.5 6.72 Sidewall sl tst 28.5 1.79 Sidewall ss;vf-fgr,vsl ty 31 .1 47 . Sidewall

coal 32.0 19. Sidewall ss;f-cgr,sl ty 26.1 21 8. Sidewall s arne 27.2 114. Sidewall coal 38.0 - - S i dewall ss;f-mgr,vsl ty 29.5 46. S i dewall

ss;f-cgr,sl slty 33.7 976. Sidewall ss;f-mgr,vshy 26.2 88. S i d e w a l l sl tst;sdy 29.8 2.22 Sidewall ss;vf-fgr,vsl ty 30.1 11. S i dewall s1tst;ss lam 27.6 0.62 S i dewall

ss;f-cgr,sl ty 28.1 162. Si dewall ss;vf-fgr,sl ty 29.5 9.89 Sidewall s1tst;sl sdy 29.1 1.16 S i dewa 1 1 ss;vfgr 25.4 73. Core 1 ;frac s arne 25.6 1.60 Core 1

sl tst;sdy , s i d 16.4 0.07 Core 1 sl tst;sid 25.7 136. f r ac same 26.9 65. f rac ss;vf-fgr 25.5 24. same;fn carb incls 26.8 117.

Table 1. POROSITY AND PERMEABILITY Norton 2

Depth Porosi ty Permeabi 1 i ty (feet) Lithology (Percent) (Mi 1 1 idarcies) Remarks

5452.0 sl tst;sl sdy,sid 27.8 0.90 Sidewall 5536.0 ss;vf-mgr,mica sc carb

i ncl s 18.6 93. Sidewall 5626.0 sltst 27.5 173. f rac 5720.0 ss;vf-fgr,mica 23.9 2.52 Si dewall 5780.0 same 23.7 17. Sidewall

5794.5 ss;vf-mgr,sc fos 20.5 1.29 Core 2 5796.5 same 23.2 5.88 Core 2 5799.5 ss;vf-fgr ,shy ,mica 7.8 0.54 Core 2 5801.4 ss;vf-fgr,foss ,vcalc 1.5 0.15 Core 2 5836.0 ss;vf-fgr,mica,fn carb

i ncl s 25.3 12. S i dewall

5890.0 ss;vf-mgr,fn carb incl s 27.9 115. Sidewall 5923.0 ss;vfgr,sl shy 22.3 2.97 Sidewall 6010.0 ss;vf-fgr 28.2 123. Sidewall 6020.0 same 30.8 33. Sidewall 6162.0 same;sl tst inbd 28.0 7 6. Si dewall

@ 6224.0 ss;vf-mgr 31 .2 321. S i dewall 6240.0 same 28.4 195. Sidewall 6342.0 ss ; vf gr 22.9 5.24 Sidewall 6370.0 ss;vf-mgr,mica 30.3 162. Sidewall 6466.0 ss;vf-fgr,mica,carb lams 28.2 98. Sidewall

6637.0 same 23.2 21 . S i dewa 1 1 6730.0 ss;vfgr,mica 20.2 2.56 Sidewall 6750.0 sltst 25.5 0.62 Si dewall 6792.0 ss;vfgr 23.3 16. Sidewall 6859.0 ss;vf-fgr,mica 30.8 84. Sidewall

6876.0 same 30.7 242. Sidewall 6909.0 saae;carb 1 a~ns 22.4 61, Si dewall 6952.0 sarne;carb 1 ams 29.5 79. Sidewall 7020.6 ss;vf-fgr,mica,fn carb

i ncl s 15.3 0.61 Core 3 7026.0 sl tst;mica 20.3 0.78 Sidewall

7030.7 ss;vf-mgr,mica,fn carb 1 ams 20.5 11. Core 3

7032.5 ss ;vf-fgr ,tnica,carb 1 ams 14.4 0.74 Core 3 7034.3 ss;vf-fgr,mica 21 .O 7.64 Core 3 7036.5 ss;f-mgr,mica 28.5 543. Core 3

a 7038.6 ss;vf-mgr ,mica,fn carb 1 ams 17.7 1.27 Core 3

Tab1 e 1 . POROSITY AND PERMEABILITY Norton 2

Depth ( f e e t )

P o r o s i t y P e r m e a b i l i t y L i tho1 ogy (Percen t ) (Mi 11 i d a r c i e s ) Remarks

ss ;v fg r ,m ica ,s l t s t i n b d 22.5 23. S idewa l l ss;vf-mgr,mica, f n ca rb

1 ams 20.0 7.98 Core 3 ss;f-mgr,mica 26.3 183. Core 3 same;fn ca rb lams 21.2 40. Core 3 ss ; v fg r ,mica 25.3 - - s l t s t ; sdy ,mica 16.5 6.03 S idewa l l ss ;v f - fgr ,mica 24.4 67. S idewa l l sh 16.0 - - S idewa l l ss;vf- fgr,mica 24.1 42. S idewa l l same 26.1 173. S idewa l l

s l t s t ; sdy 18.1 181. f rac ss ;v fg r , fn ca rb lams 22.5 22. S idewa l l s ame 18.7 117. f rac same 18.7 10. S idewa l l s l tst ;sdy,mica 7.3 0.01 Core 4

ss;vf - f g r ,mica 11.4 0.22 Core 4 ss;vfgr,mica,sl ty,shy 10.1 0.67 Core 4 s l t s t ; s d y 11.6 0.16 Core 4 ss ; v fg r 23.0 12. S idewa l l s l t s t ;vcarb 19.8 127. f rac

ss;vf- fgr,mica,fn ca rb 1 ams 22.9 39. S idewa l l

same 24.0 57 . Sidewa l l sh 16.6 - - f r ac ss;v f - fgr ,mica 25.8 13. S i dewal l ss ;v fgr ,carb 1 arns 8.6 0.17 Core 5

ss ; v f - f g r , c l y 13.6 0.19 Core 5 same 14.6 0.51 Core 5 s ame 12.5 0.14 Core 5 same 11.6 0.07 Core 5 s ame 16.0 1 .47 Core 5

same 14.7 0.39 Core 5 same 15.5 0.69 Core 5 same 15.3 0.62 Core 5 same 17.5 4.28 Core 5 ss;vf- fgr,mica,carb lams 23.4 40. S idewa l l

T a b l e 1. POROSITY AND PERMEABILITY Norton 2

Depth (feet)

Porosity Permeability L i tho1 ogy (Percent) (Millidarcies) Remarks

sl tst;sdy,carb 1 arns 19.2 14. Sidewall s ame 18.3 15. Si dewa 1 1 ss;vfgr,mica,carb incls 23.4 16. Sidewall sh 19.9 106. f rac sl tst;sdy 6.3 1.59 Core 6;sl f r a c

same 4.4 0.32 Core 6 s ame 3.8 0.03 Core 6 ss;vfgr,vcalc 25.1 10.00 Sidewall ss;vfgr,sl calc 23.9 14. Si dewall same 23.7 26. Si dewall

same 23.2 147. Sidewall same 25.3 48. S i dewall same;mica 18.5 17. Sidewall ss;vf-fgr ,micd,sh inbd 3.4 2.63 Core 7 sl tst;sdy 3.0 0 . 02 Core 7

ss;vf-fgr,mica,shinbd 3.7 0.07 Core 7 sh 3.1 21 5. Core 7;frac ss;vfgr,vshy 2.9 0.22 Core 7 same 5.9 0.30 Core 8 ss;vf-fgr,mica 21 .5 - - Sidewall

ss;vf-mgr,shy,calc 20.2 - - Sidewall ss;vfgr,mica,carb lams 21.4 - - Sidewall ss;vf-fgr,mica,calc 21.6 34 Sidewall ss;vf-mgr,mica,sl calc 17.7 8.79 Sidewall ss;vf-fgr,mica,sl calc 20.4 32. Sidewall

ss;vf-fgr,mica,carb incls 12.2 0.03 Core 9

ss;vf-mgr,mica-,fn ca rb i ncl s ,sl cal c 9.0 0.05 Core 9

same 11.7 - - Core 9 ss;vf-fgr,mica, sl calc 24.9 - - Sidewall ss;vf-mgr,mica,fn carb incls, sl calc 12.2 0.02 Core 9

same;sc peb 9.3 0.06 Core 9 same;sc peb 7.2 0.03 Core 9 same;sc peb 7.2 0.08 Core 9 sarne;sc peb 8.9 0.02 Core 9 ss;vf-fgr,mica 21 .3 - - Sidewall

Tab1 e 1. POROSITY AND PERMEABILITY N o r t o n 2

Depth ( f e e t )

P o r o s i t y P e r m e a b i l i t y L i t h o l o g y ( P e r c e n t ) ( M i l l i d a r c i e s ) Remarks

ss ;v fg r , shy 3.8 0.02 Core 10 same 3.8 0.10 Core 10 same 3.9 0.03 Core 10 s s ; v f - f g r , c a l c 7.5 0.24 Core 10 ss;vf-mgr,mica,s l c a l c 26.2 119. S i d e w a l l

same 23.1 41 . Sidewall ss;vfgr ,shy,vmica 15.6 - - Sidewall ss;f-mgr,mica 11.2 0.14 Core 1 1 s arne 11.3 0.30 Core 1 1 ss ; f -cgr ,mica 11.7 0.23 Core 1 1

ss;f-mgr,mica 12.6 0.21 Core 1 1 s ame 6.8 0.1 7 Core 1 1 ;FD s ame 10.9 0.14 Core 1 1 s arne 1 1 .I 0.14 Core 1 1 same;mica 5.9 0.02 Core 1 1

ss; f -cgr , rn ica 12.0 0.32 Core 11 s ame 10.3 0.29 Core 1 1 ;FD same 11.1 3.47 Core 1 1 same 11.8 0.16 Core 1 1 same 1 1 .4 0.43 Core 11;FD

ss;vf -mgr,mica 7.5 0.09 Core 1 1 ss ; f -cgr ,mica 12.1 0.23 Core 1 1 s ame 8.4 0.11 Core 11 same 12.3 0.23 Core 1 1 s ame 10.7 0.21 Core 1 1

s ame 12.5 0.18 Core 1 1 s ame 9.4 2.43 Core 1 1 ; F 3 ss;vf-mgr,mica,sl ca lc 21.8 - - Si dewall ss ; f -cgr ,mica 11.1 0.14 Core 1 1 s ame 9.7 0.14 Core 1 1

s ame 8.1 0.1 2 Core 1 1 ;FD same 12.8 0.37 Core 1 1 same 9.6 0.1 5 Core 1 1 ;F9 ss;f-rngr,mica,fn c a r b

1 arns 10.6 0.96 Core 1 1 ss;f-mgr,mica 11.9 0.14 Core 1 1

Tab le 1. POROSITY AND PERMEABILITY Nor ton 2

Depth P o r o s i t y P e r m e a b i l i t y ( f e e t ) L i tho1 ogy ( p e r c e n t ) ( M i l 1 i d a r c i e s ) Remarks

13422.3 same 7.1 0.05 Core 11 13423.1 same 10.1 0.1 5 Core 11;FD 13424.3 same 11.7 0.11 Core 11 13425.4 same;fn c a r b lams 10.4 0.11 Core 11 13730.0 ss;vf-mgr,mica,sl c a l c 19.5 - - S i d e w a l l

14175.0 same;fn c a r b lams, ca l c 17.2 38. 14487.7 s l t s t 0.6 0 . 02 Core 12 14493.9 same 3.0 0.02 Core 12 14494.4 same 2.5 (0.01 Core 12 14859.7 1s 0.9 (0.01 Core 13

14869.3 same 14871.6 same 14888.3 same 14889.2 same

0.6 0.01 Core 13 0.7 0.01 Core 13 0.8 2 . 01 Core 13 1 a0 0.03 Core 13

P o r o s i t y ( p e r c e n t )

5 10 2 5 5 0

F i g u r e 34. Plot o f a v e r a g e p o r o s i t y a g a i n s t d e p t h f o r c o n v e n t i o n a l c o r e s a n d s t o n e s a m p l e s f r o m N o r t o n S o u n d COST No.2 we l l

96

Figure 35. Plot of average permeability against average porosity for conventional core sandstone samples from Norton Sound COST No. 2 well

P e r m e a b i l i t y ( m D )

.o 1 . 1 1

a Pos tdepos i t i ona l p o r o s i t y and p e r m e a b i l i t y r e d u c t i o n a r e p r i m a r i l y due t o

compaction and d u c t i l e g r a i n deformat ion i n t h e m a t r i x - r i c h sandstones encountered

i n t h e we1 1. Authigert ic cementat ion has p layed a s u b s i d i a r y r o l e i n t h e

d e t e r i o r a t i o n o f r e s e r v o i r qua1 i ty. P y r i t e , smect i t i c c l ay, and s i d e r i t e a r e

p resen t as au th i gen i c cements i n samples from c o r e 1 (4623 t o 4634 f e e t ) . C a l c i t e

cement i s f i r s t r e p o r t e d i n samples f rom c o r e 2 (5793 t o 5802 f e e t ) , and a u t h i g e n i c

q u a r t z and k a o l i n i t e a r e f i rs t repo r ted i n samples f rom c o r e 3 (7018 t o 7049

f e e t ) . A n k e r i t e cement i s f i r s t r e p o r t e d i n samples f rom c o r e 4 (7993 t o 8022

f e e t ) , and au th igen i c chl o r i t e i s f i r s t r epo r ted i n samples f r o m c o r e 9 (12,212

t o 12,241.5 f ee t ) ,

Hydrocarbons

• 3 u r i n g t h e d r i l l i n g o f t h i s w e l l , good gas shows c o n s i s t i n g o f methane ~ i t h

l e s s e r amounts o f ethane, propane, and butane were encountered between 12,190 and

14,460 f ee t . An examinat ion o f t h e geophys ica l l o g s shows neu t ron -dens i t y gas

anomal ies f o r much o f t h e sandstone and in te rbedded coa l between 12,880 and

13,942 feet , No t e s t s were run t o eva lua te t h e degree o f gas s a t u r a t i o n i n t h e

sandstone beds w i t h neu t ron-dens i ty gas anomalies. These anomalies p robab ly

represen t p a r t i a1 s a t u r a t i o n o f t h e sandstone w i t h gas generated i n ad jacen t

coa l beds and unable t o m i g r a t e f u r t h e r because of l ow p e r m e a b i l i t y . Th i s sequence

might conce i vab l y be p r o d u c t i v e elsewhere i n t h e bas in .

GEOCHEMISTRY

NORTON SOUND COST WELL NO. 2

by

TABE 0. FLETT AND DAVID BLUNT

I n t r o d u c t i o n

The o rgan i c geochemistry f o r t h e COST No. 2 w e l l was designed t o eva lua te

the pet ro leum source p o t e n t i a l o f rocks i n t h e eas te rn r e g i o n af t h e Nor ton

Sound l ease area. The a n a l y t i c a l program was recommended and undertaken by

Robertson Research (U .S. ) , Inc., and was approved, w i t h modi f i c a t i o n s , by

A t l a n t i c R i c h f i e l d O i l Company (ARCO) who ac ted as ope ra to r on b e h a l f o f a

group o f companies. A1 1 o rgan ic geochemical analyses f rom Nor ton b a s i n COST

No. 2 w e l l sumlnarized i n t h i s r e p o r t were ob ta i ned f rom Robertson Research

(U.S.), Inc., (Dow, 1982). A l l depths were ~neasured f r o m t h e Ke l l y Bushing

which was l o c a t e d 104.7 f e e t above mean sea l e v e l and 154 f e e t above t h e sea

f l oor.

Samples were se lec ted by ARCO and i n c l u d e c u t t i n g s (226 sampl es) , s i d e w a l l

co res ( 1 64 samples) and t h i r t e e n convent iona l co res ( 5 3 samples). C u t t i n g

samples a t 60- foot i n t e r v a l s were canned and analyzed f o r headspace gas, washed,

descr ibed, and a r e p r e s e n t a t i v e sample s e l e c t e d f o r t o t a l o rgan i c carbon (TOC)

ana l ys i s . Samples w i t h about 0.3 we igh t percen t TOC were analyzed w i t h rock -eva l

p y r o l y s i s . Samples f rom c u t t i n g s and s i dewa l l cores a t 300- foo t i n t e r v a l s and

sampl es f rom each convent iona l co re were se lec ted f o r kerogen i s o l a t i o n , v i t r i n i t e

r e f l ec tance , spore c o l o r a t i o n index, and e lementa l a n a l y s i 5 . Soxhl e t e x t r a c t i o n ,

e l u t i o n chromatography, and s a t u r a t e f r a c t i o n gas chromatography were r e s t r i c t e d

t o conven t i ona l c o r e samples. The o r i g i n a l da ta i s on f i l e a t t h e M ine ra l s

Management, Serv ice , 800 A S t r e e t , Anchorage, A1 aska, and i s a v a i l a b l e f o r

exarni na t i on ,

Geothermal Grad ien t

The apparent mean geothermal g rad ien t s f o r t h e No. 2 w e l l were computed

f rom raw da ta p l o t t e d on F i g u r e 36. Observed temperatures from 1000 f e e t below

t h e K e l l y Bushing t o 14,870 f e e t (Bottom Hole Temperature [BHT]) a r e taken

f rom t h e temperature log . Two runs were ~nade below 11,700 f e e t which r e s u l t e d

i n two da ta sets. The mean thermal g r a d i e n t f o r t h i s p a r t of t h e No. 2 w e l l was

computed f rom 275°F a t 11,000 f e e t t o t h e maximum BHT of 370' F a t 14,870 f e e t .

The geothermal g r a d i e n t f rom 1000 f e e t t o 11,000 f e e t may be computed by t a k i n g

the a r i t h m e t i c mean of t h e g r a d i e n t s f o r t h e 500- foo t increments w i t h i n t h i s

i n t e r v a l or by comput ing t h e mean va lue f o r t h e two extreme measurements a t

1000 f e e t and 11,000 f e e t .

Organic Richness

To ta l o rgan i c carbon con ten t from c u t t i n g s , s i d e w a l l cores, and convent iona l

co res a r e d i sp layed on P l a t e 1. From t h e sea f l o o r t o 3,540 f e e t below t h e

K e l l y Bushing, TOC values f rom s idewa l l cores a r e marg ina l , averag ing 0.61

percent . From 3540 t o 4570 f e e t , s i g n i f i c a n t amounts o f coa l Dccur i n t h e

samples and TOC values are h i g h l y v a r i a b l e rang ing f rom around 1 pe rcen t

T e m p e r a t u r e O F

D e p t h T e m p e r a t u r e

( f t ) ( 'OF>

1 ,000 73 3,000 1 1 2 5.000 1 5 1 7,000 190 9,000 2 3 3

1 1,000 2 7 5 14.87 0 B H T 370

M e a n t h e r m a l g r a d i e n t

1,000 t o 1 1,000 f t : 2.02 OF/ 100 f t

M e a n t h e r m a l t o 14,870 f t CTD)

g r a d i e n t : 2.50 " F / 1 0 0 f t

F i g u r e 36. T e m p e r a t u r e log d a t a f r o m C O S T W e l l 2, .Nor ton Sound, 48.5 hrs a f t e r c i r c u l a t i o n ceased.

[Data f r o m Sohlumberger ~ i r n i t e d

e t o a maximum o f 42 percen t . From 4570 t o 6410 f e e t , TOC v a l ues a r e g e n e r a l l y

l e s s t han 1 percen t w i t h t h e excep t i on o f a few c o a l - b e a r i n g samples. Between

6410 and 9200 f e e t , coa l aga in causes h i g h l y e r r a t i c TOC measurements w i t h a

maximum va lue o f 61.47 percent . Most s i d e w a l l co res i n t h i s i n t e r v a l do n o t

exceed 4 pe rcen t TOC. Whi le h igh , t h e y a r e no t n e a r l y as h i g h as c u t t i n g s

samples, which c o u l d i n d i c a t e t h a t coa l sequences a r e t h i n and i n t e r m i t t e n t o r

t h a t c u t t i n g s samples a r e be ing contaminated by superad jacen t coa l 1 ayers.

Good o rgan i c va lues occur i n s i l t s t o n e s f r om 9773 t o 12,035 f e e t . TOC averages

1.38 pe rcen t i n t h i s i n t e r v a l . E r r a t i c o rgan i c carbon va lues occur from 12,152

t o 14,318 f e e t , and va lues a r e as h i g h as 54 and 55 percen t where coa l i s

p resen t . From 14,460 t o 14,885.3 f e e t , TOC va lues f r o m c o r e samples a re l e s s

t h a n 0.1 4 percent . H igher va lues from c u t t i n g s samples r e f 1 e c t con tam ina t i on

f r om superad jacen t sediments.

The CIS+ t o t a l o rgan i c e x t r a c t i s r e p o r t e d f rom conven t i ona l co res f o r

depths from 4628 t o 14,861 f e e t i n t h e No. 2 w e l l ( F i g u r e 37) . C15+ e x t r a c t a b l e

biturnen c o n t e n t o f kerogen, based upon GeoChem L a b o r a t o r i e s , Inc , exper ience

(Bay1 i ss and Smith, 1980), i s ve ry good t o exce l 1 e n t (2000 pprn t o 4000 ppm+)

f rom 7,020 t o 8,020 f ee t and good t o ve r y good (1000 ppm t o 4000 pprn) f rom

11,170 t o 12,213 f e e t . Favorab le C i s + e x t r a c t a b l e b i tumen va lues a l s o seem

t o occur more f r e q u e n t l y i n zones c o n t a i n i n g coa l and carbonaceous m a t e r i a l . Cis+

b i tumen t o o rgan i c carbon r a t i o s a r e i n excess of 0.01, and maximum va lues a r e

app rox ima te l y 0.1 1, Values f o r t h i s r a t i o c i t e d by A lb rech t , Vandenbroucke,

and ~ a n d e n ~ u g (1976) f o r e x t r a c t s f rom s i m i l a r kerogen i n Cretaceous rocks

C15+ Extractable Organic Matter

( P P ~ )

Figure 37. Organic Richness CIS+ E x t r a c t a b l e O r g a n i c Matter f r o m C o n v e n t i o n a l Cores .

e found i n t h e Doula Basin, Camaroon, A f r i c a , reach a maximum o f 0.11. T i s s o t

and Welte (1978) i n d i c a t e t h a t when t h e bi tumen t o TOC r a t i o exceeds 0.20, t h e

va lues a r e abnormal ly h i g h and may i n d i c a t e t h e presence o f nonindigenous bitumens.

D e s c r i p t i o n o f Kerogen

Kerogen was examined i n r e f l e c t e d and t r a n s m i t t e d l i g h t . Resu l t s o f t h e

r e f l e c t e d l i g h t pe t rography and t h e hydrogen t o carbon r a t i o ( H / C ) o f t h e

kerogen f rom chemical analyses a r e dep i c ted i n F i g u r e 38.

Three pe t rog raph i c c l asses o f kerogen p l u s amorphous m a t e r i a l , a subgroup

w i t h i n t h e e x i n i t e o r l i p t i n i t e ca tagory , a r e r e p o r t e d i n t h i s s tudy as f o l l o w s :

1. Arnorphous (a1 ga l o r d i s s o l ved , col 1 o i da l m a t t e r )

2. E x i n i t e (herbaceous, li p i d - r i c h re1 i c s )

3. V i t r i n i t e (woody and hurnic components)

4. I n e r t i n i t e (hard, ca rbon - r i ch , non reac t i ve b r i t t l e p a r t i c l e s )

Dow (1982) s t a t e s t h a t i t has been t h e exp2r ience o f Robertson Research (U.S.),

Inc., t h a t samples w i t h l e s s than 35 pe rcen t amorphous kerogen w i l l y i e l d p r i m a r i l y

d r y gas and t h a t o i l source beds c o n t a i n 65 percen t o r more o f t h e o i l - g e n e r a t i n g

components (amorphous + e x i n i t e ) . He adds t h a t i n t e r m e d i a t e m ix tu res w i l l

expel primarily wet gas and condensate, a l though a complete t r a n s i t i o n p robab ly

e x i s t s . Amorphous keroyen i n excess of 35 percen t o f t h e t o t a l kerogen occurs

i n a dominan t l y s i l t s t o n e u n i t between 2400 and 3200 f e e t and between 9200 and

Type of Kerogen

f-J . . . . . . . . Amorphous

Ex in i te

0 V i t r i n i t e

Inel'tinite Flours 38. Claasificatlon of Organic Matter .

e 12,200 f e e t i n a sha l y s i l t s t o n e l i t h o l o g y . I n t h i s l owe r u n i t t h e amorphous

con ten t o f t h e kerogen exceeds 65 percen t i n seve ra l i ns tances , I n c o a l y

i n t e r v a l s and a t depths g r e a t e r than 12,200 f e e t , v i t r i n i t e maceral s dominated

t h e kerogen w i t h percentages o f v i t r i n i t e g e n e r a l l y i n excess o f 60 o r 65

percen t .

Elemental a n a l y s i s da ta a r e i n good agreement w i t h t h e v i s u a l i d e n t i f i -

c a t i o n o f kerogen. The H/C r a t i o ranges f rom about 1.2 near t h e su r face

t o a minimum o f 0.57 a t 14,640 f e e t , Hunt (1979) i n d i c a t e s t h a t 1.2 i s a

t y p i c a l H/C va l ue f o r herbaceous kerogen and 0.72 c h a r a c t e r i s t i c o f woody

kerogen, These a r e forms o f e x i n i t e and v i t r i n i t e , r e s p e c t i v e l y , I t

appears t h a t much o f t h e kerogen i n t h e sediments pene t ra ted by t h i s

we1 1 i s woody, herbaceous m a t e r i a l d e r i v e d from a t e r r e s t r i a l source, Th i s

i n t e r p r e t a t i o n i s suppor ted by p y r o l y s i s .

The hydrogen and oxygen i n d i c e s from p y r o l y s i s o f s i d e w a l l c o r e sanlpl es

a r e p l o t t e d on a m o d i f i e d Van Kreve len diagram, F i g u r e 39. The da ta p l o t s

a lmost t o t a l l y a l ong t h e t ype 111 m a t u r a t i o n curve. Those samples w i t h hydrogen

i n d i c e s g r e a t e r than 150 t h a t p l o t i n t h e v i c i n i t y o f t h e t y p e I and t y p e I 1

curves a t r e l a t i v e l y h i g h l e v e l s o f thermal m a t u r i t y a r e d e r i v e d comp le te l y

frorn t h e c o a l y sequences of t h e l i t h o l o g y , The s i n g l e h i g h l y anomalous da ta

p o i n t ( H I = 494) i s f rom a s i d e w a l l c o r e a t 6630 f e e t . H/C f rom e lementa l

ana lyses i s 0.88, which i s n o t anomalously h i g h f o r t h i s kerogen. There i s no

apparent reason t o assume t h a t any o f t h e kerogen analyzed rep resen t s e i t h e r

t y p e I o r t y p e I I.

M a t u r a t i o n

The l e v e l o f thermal a l t e r a t i o n a t t a i n e d by ca rbon-bear ing sediments can

b e eva lua ted i n a v a r i e t y o f ways. F i g u r e 40 c o n t a i n s w e l l p r o f i l e s o f t h e

random v i t r i n i t e r e f l e c t a n c e (Ro), t h e spore c o l o r a t i o n i ndex ( S C I ) , kerogen

f l u o r e s c e n c e i n t e n s i t y , T2-max f rom t h e second p y r o l y s i s response, and t h e

carbon p re fe rence i ndex ( C P 1 ) .

Rober tson Research (U.S.), Inc. , (Appendix) r e p o r t s t h a t t h e abundance o f

t e r r e s t r i a1 kerogen i n most sampl es analyzed produced ve ry good v i t r i n i t e

r e f l e c t a n c e da ta w i t h t h e r e s u l t t h a t t he Ro p r o f i l e i s t h e most r e l i a b l e

i n d i c a t o r o f thermal m a t u r i t y f o r t h e No. 2 we l l . Histograms o f Ro measurements

a r e g e n e r a l l y unimodal. The o n l y s i g n i f i c a n t problems r e p o r t e d were h igh

rank, r e c y c l e d o rgan i c m a t t e r i n some s h a l l ow samples, occas iona l o x i d i z e d

v i t r i n i t e , s o l i d b i tumen and p s e u d o v i t r i n i t e , and minor cav i ng i n a few o f the

c u t t i n g s samples.

Ro va lues reach 0.6 percen t , t h e l owe r l i m i t of peak o i l gene ra t i on (I-lunt,

1979) , a t app rox ima te l y 10,700 f e e t below t h e K e l l y Bushing. Ro i nc reases

c o n t i n u o u s l y t o a dep th o f about 12,100 f e e t where t h e r e i s a d i scon t i nuous

i nc rease i n Ro f r om about 0.7 t o 1.0 percen t . The Ro va lues then i n c r e a s e

c o n t i n u o u s l y t o 14,330 f e e t where a maximum va lue o f 1.46 pe rcen t was observed.

O i l c o u l d be generated and p reserved f rom 10,700 f e e t o r a l i t t l e l e s s t o a t

l e a s t 14,300 f e e t , and gas c o u l d he generated and p reserved from 12,100 f e e t

t o t o t a l dep th o f t h e No. 2 w e l l a t t h i s l o c a t i o n .

Dow (1982) i n t e r p r e t s t h e Ro anomaly a t 12,100 f e e t as be ing t h e r e s u l t o f

an unconforrni ty. By p r o j e c t i n g t h e l owe r segment o f t h e Ro p r o f i l e up h o l e t o

about 0.7 percen t , i t i s p o s s i b l e t o e s t i m a t e t h a t severa l thousand f e e t o f

eroded s e c t i o n a r e unaccounted f o r i n t h i s w e l l (Dow, 1977). The con t inuous

n a t u r e o f t h e Ro curve, which p r o j e c t s t o n e a r l y 0.2 pe rcen t a t t h e p resen t

su r face , i n d i c a t e s t h a t ve ry l i t t l e e r o s i o n has occur red above t h e anomaly and

t h a t sed imen ta t i on was e s s e n t i a l l y con t inuous t o about 12,000 f e e t . A

c o r r e l a t i v e anomaly appears t o occur a t approx i rna te ly 11,900 feet ' i n t h e S C I

p r o f i l e .

The spore c o l o r a t i o n index i s es t imated by a s s i g n i n g a va lue, on a s c a l e

o f 1 t o 10, t o t h e c o l o r o f spores and p o l l e n observed i n t r a n s m i t t e d 1 i g h t .

T h i s techn ique i s most u s e f u l i n t h e l owe r m a t u r a t i o n ranges because, as the

spores and p o l l e n become more mature, t h e y become opaque, and i t i s d i f f i c u l t

t o e v a l u a t e s u b t l e changes i n c o l o r . A c o r r e l a t i o n c h a r t p rov i ded by Robertson

Research (U.S.), Inc., (Dow, 1982) suggests t h a t t h e l owe r t h r e s h o l d o f peak o i l

g e n e r a t i o n f o r S C I va lues i s approx imate ly 3.5 o r 3.6 and t h e upper va l ue

app rox ima te l y 7.4 o r 7.5. These 1 i m i t i n g va lues a r e approx imate ly e y u i v a l e n t

t o 0.6 and 1.4 pe rcen t r e s p e c t i v e l y on t h e v i t r i n i t e r e f l e c t a n c e sca le .

Dow (1982) s t a t e s t h a t S C I da ta from t h e No. 2 w e l l a r e o f u n u s u a l l y poor

q u a l i t y owing t o an abundance of r e c y c l e d o r o x i d i z e d o rgan i c m a t t e r and apparent

d i s c o l o r a t i o n , p o s s i b l y caused by b i tuminous m a t e r i a l . The d i s c o l o r a t i o n was

p a r t i c u l a r l y t roub lesome above 8000 f e e t . Never the less, t h e m a t u r a t i o n p r o f i l e

developed f r om SCI values c l o s e l y resembles t h e m a t u r a t i o n p r o f i l e s f rom Ro

and T2-max values. SCI va lues imp l y t h a t adequate m a t u r i t y f o r gene ra t i on o f

hydrocarbons beg ins between 10,200 and 10,600 f e e t i n t h e No. 2 w e l l . A

d i s con t i nuous o f f s e t i n t h e m a t u r a t i o n p r o f i l e occurs a t about 11,900 f e e t , and

SCI va lues from t h i s dep th t o t h e bot tom of t h e w e l l range between 6 and 7,

near maximum va lues f o r o i l genera t ion .

The i n t e n s i t y o f kerogen f l uorescence i nc reases w i t h i n c r e a s i n g m a t u r i t y .

A t 9230 f e e t t h e f l uo rescence i n t e n s i t y assoc ia ted w i t h t h e opaque kerogen

f rom s i d e w a l l co res i s ve r y h i g h and remains ve r y h i g h t o a depth o f 13,558

f e e t , a t which p o i n t i t decreases r a p i d l y . Th i s d rop i n kerogen f l uo rescence

i n t e n s i t y appears t o cor respond w i t h reduced l e v e l s o f o rgan i c r i chness and an

i nc rease i n t h e c o n t e n t o f v i t r i n i t i c kerogen a t t h e expense o f e x i n i t e m a t e r i a l .

The abruptness i n t h e r e d u c t i o n of t h e f l uo rescence i n t e n s i t y suggests t h a t i t a i s r e l a t e d t o a change i n kerogen compos i t i on r a t h e r than t o t h e p r o g r e s s i v e

i nc rease i n m a t u r i t y , though i n c r e a s i n g therma l m a t u r i t y i s p robab l y a c o n t r i b u t i n g

f a c t o r .

6''

Barke r (1972), C laypool and Reed (1976) , and E s p i t a l i e and o t h e r s (1977),

have suggested t h a t T2-max, t h e tempera tu re a t which maximum e v o l u t i o n o f

the rma l hydrocarbons occurs d u r i n g p y r o l y s i s , can be used t o c h a r a c t e r i z e t h e

degree o f thermal m a t u r a t i o n o f kerogen, However, these measurements a r e

i n f l u e n c e d by t h e l a b o r a t o r y ' s i n s t r u m e n t a t i o n and techn ique , t h e r a t e o f

hea t i ng , and 5y t h e t y p e of kerogen, Type I11 kerogen, f o r example, tends t o

e x h i b i t l o w e r T2-max va lues than types I and I I ( T i s s o t and We1 t e , 1978).

Rober tson Research (U.S.), lnc. , suggests t h a t t h e zone o f peak o i l

gene ra t i on i s r ough l y d e f i n e d by t h e l i m i t i n g T2-max va lues 435" and 470" C.

These va lues occur a t approximately 10,600 and 13,600 f e e t r e s p e c t i v e l y i n t h e

No. 2 w e l l . The r e l a t i v e l y h i g h T2-rnax va lues i n t h e upper p a r t o f t h e

l i t h o l o g i c s e c t i o n a r e caused by r e c y c l e d o rgan i c m a t t e r t h a t cannot be screened

f r om p y r o l y s i s analyses, a l t hough i t f r e q u e n t l y can be when Ro measurements a r e

made. I n s p i t e o f t h i s , t h e T2-max da ta p l o t s as a con t inuous p r o f i l e very

s i m i l a r t o t h e Ro p r o f i l e . The Ro anomaly a t 12,100 f e e t i s no t apparent i n

t h e T2-max da ta , p o s s i b l y owing t o t h e g r e a t e r s t a t i s t i c a l v a r i a t i o n i n h e r e n t

i n t h i s a n a l y t i c a l technique.

C P I va lues f o r samples f rom conven t iona l co res were computed u s i n g t h e

o r i g i n a l Bray and Evans formul a (C24 th rough C34). The s h a l l owest o b s e r v a t i o n

i s 1.19 f r om a sample a t 4525 f ee t . Values i nc rease t o 2.96 a t 8727 f e e t dnd

t h e n decrease t o a minimum o f 1.07 a t 13,405 f e e t below t h e Kelly Bushing.

CPI va lues appear t o approach 1.3 between 11,000 and 12,000 f e e t . Values be low

12,000 f e e t p r o j e c t toward an asympto t i c l i r n i t o f about 1 .l. Gas chro~natogra~ns

f rom conven t i ona l c o r e samples a t 11,170 and 12,213 f e e t a r e reproduced i n

F i g u r e 41. The change f rom a bimodal t o a unimodal d i s t r i b u t i o n o f p a r a f f i n s

w i t h a r e d u c t i o n o f l o n g e r p a r a f f i n and napthene molecu les p l u s t h e r e d u c t i o n .

o f t h e C P I va lues be low 12,000 f e e t a l l t end t o suppor t t h e hypo thes i s t h a t a

s i g n i f i c a n t i nc rease i n thermal m a t u r i t y has occur red i n t h i s i n t e r v a l .

PrIPh = 6.09

CPI - 1.30

Depth: 12213 f e e t

PrlPh = 4.00

CPI = 1.19

Figure 4 1 . R e p r e s e n t a t i v e C 1 S + G a 5 C h r o m a t o g r a m s Prom c o n v e n t i o n a l c o r e s a m p l e s showing A l k a n e d i s t r i b u t i o n .

There i s good general agreement among t h e i n d i c a t o r s o f therrnal m a t u r i t y

t h a t t h e onse t of ma jo r o i l gene ra t i on shou ld occu r a t approx i rna te ly 10,700 f e e t

a t t h i s l o c a t i o n and t h a t a s i g n i f i c a n t m a t u r a t i o n anomaly e x i s t s a t about

12,100 fee t . The base o f t h e zone o f peak o i l gene ra t i on i s n o t as d i s t i n c t as

t h e upper boundary b u t i t appears t o occur a t 14,000 t o 14,300 f e e t . Gaseous

hydrocarbons c o u l d be generated and p reserved be low 12,100 f e e t i n t h i s w e l l

and a t c o n s i d e r a b l y sha l l owe r depths i f generated f rom coa l o r by microorganisms.

Hydrocarbon Source P o t e n t i a1

Organic r i chness , headspace gas and wetness, g e n e t i c p o t e n t i a l and

p r o d u c t i v i t y i ndex f r om p y r o l y s i s a r e a l l d i s p l a y e d on F i g u r e 42. Wetness f o r

t h i s r e p o r t i s d e f i n e d as [ C Z + C 3 + C 4 ] : L C 1 + C 2 + C 3 + Cq]. The

l a r g e r headspace gas va lues a re r e l d t e d t o anomalous o rgan i c carbon l e v e l s

t h a t g e n e r a l l y occur i n c o a l y 1 i t h o l o g i c sequences. The wetness r a t i o c l e a r l y

i n d i c a t e s t h a t u n t i l Ro exceeds 0.6 pe rcen t , t h e headspace gas i s al lnost e n t i r e l y

composed o f methane. Dow (1982) no tes t h a t i f p r i m a r i l y o i l source beds were

p resen t , e s p e c i a l l y be low 10,000 f e e t , t h e wetness r a t i o shou ld be rnore than

90 pe rcen t and t h a t pentane and h e a v i e r a lkanes shou ld be more abundant than t h e y

are.

The sum S1 + 52 from p y r o l y s i s i s termed t h e gene t i c p o t e n t i a l by T i s s o t

and Wel te (1978) because i t accounts f o r b o t h t y p e and abundance of o rgan i c

mat te r . They suggest t h e f o l l o w i n g t h r e s h o l d va lues f o r e v a l u a t i n g the o i l and

gas p o t e n t i a l o f source rock.

S1 + s2

Ippm)

Less than 2000

2000 t o 6000

Grea te r t han 6000

Source-Rock P o t e n t i a l

No o i 1 . Some gas.

Moderate source rock.

Good source rock.

-

The q u o t i e n t S 1 + S2 i s termed t h e t r a n s f o r m a t i o n r a t i o by T i s s o t and

Welte (1978). I t i n d i c a t e s t h e e x t e n t t o ~ h i c h t h e gene t i c p o t e n t i a l of a

kerogen has been r e a l i z e d p r o v i d e d t h a t v o l a t i l e hydrocarbons (S1) evo lved f rom

t h e kerogen a r e ind igenous.

Most o f t h e e r r a t i c S1 + $2 va lues i n excess o f 2000 ppm a r e d e r i v e d

@ f rom c o a l y 1 i t h o l o g i c sequences. However, t h e s e c t i o n from about 10,000 t o

12,250 f e e t i s l a r g e l y s i l t s t o n e and s h a l e w i t h o n l y minor amounts o f coa l .

A s i n g l e s i d e w a l l c o r e sample a t 12,230 f e e t y i e l d e d i s o and normal ?entan@ c o n t e n t s

o f 5487 and 7634 ppm, r e s p e c t i v e l y . Below 10,600 f ee t , t h e S1 + 52 values

range from 2000 t o 8980 pprn and 1 1 from 0.05 t o 0.56. The maximum +

S l + S 2 1 2 va lues were t h e r e s u l t o f p y r o l y s i s performed upon conven t i ona l c o r e 9 a t

12,214 f e e t ; a sample composed o f a ve ry f i n e , q u a r t z sandstone w i t h f r a c t u r e s

f i 11 ed w i t h b lack , s h i ney , b i tum i nous m a t e r i a1 , resembl i ng coa l .

* Robertson Research (U.S.), Inc., i d e n t i f i e d t h e s o l i d b i tuminous m a t e r i a l

as ep i - impson i t e on t h e b a s i s o f Ro and e lementa l ana l ys i s . Th is sample and a

sample o f g ray , q u a r t z i t i c , and micaceous s i l t s t o n e from t h e same co re a t

12,213 f e e t con ta ined almost 4000 ppln e x t r a c t a b l e o rgan i c m a t e r i a l t h a t produced

gas chromatograms c l o s e l y resembl ing crude o i l . The b i tuminous m a t e r i a l

con ta ined some e x t r a n-alkanes i n t h e C20 - C30 carbon number range t h a t were

n o t p resent i n the pen tane- r i ch s i l t s t o n e . The C15+ e x t r a c t s f roin t h e samples

a t 12,213 and 12,214 f e e t y i e l d e d p r i s t a n e t o phytane r a t i o s (Pr/Ph) o f 4.00

and 4.33 r e s p e c t i v e l y . Pr/Ph r a t i o s between 3.0 and 4.5 f rom t h e Carnarvon

b a s i n ( J u r a s s i c source) , Pe r th b a s i n ( c e n t r a l Dandaragan t r o u g h ) , and Papuan b a s i n

i n A u s t r a l i a a r e de r i ved f rom p a r a f f i n i c - n a p t h e n i c o i l s assoc ia ted w i t h marg ina l -

mar ine cl a s t i c sedimentary rocks o r d e l t a i c sequences w i t h some lnari ne i n f l uence

(Powel 1 and McKi r dy , 1975) .

The o rgan ic e x t r a c t s from these sarnples were c o r r e l a t e d w i t h e x t r a c t s f rom

cores 1 0 and 11 by Robertson Research (U.S.), Inc., on t h e b a s i s o f "gross

composi t ions, s a t u r a t e f r a c t i o n gas chromatograms, and key r a t i o s . " Robertson

Research (U.S.), Inc., (Appendix) concludes t h a t t h e e x t r a c t a b l e m a t e r i a l i n

c o r e 9 p robab l y o r i g i n a t e d i n t h e r m a l l y mature c l a s t i c sediments as deep as

14,000 f ee t .

Summary and Conclusions

Geochernical data f rom t h e No. 2 we l l i n d i c a t e a p redor r~ inan t l y type I T 1 hu~n ic

kerogen commonly found i n what Oemaisson (1981) has termed a " t ype C " o rgan i c

e f ac ies . Th i s f a c i e s i s t y p i c a l l y t h e p roduc t o f a m i l d l y o x i c d e p o s i t i o n a l

environment and may c o n t a i n mar ine and nonmarine sediments, s l ope and r i s e

depos i ts , and e x i n i t e r i c h c o a l s . I t i s c h a r a c t e r i z e d geochemica l ly a t an Ro o f

approx imate ly 0.5 pe rcen t i n t h e f o l l o w i n g manner:

Hydrogen Index ( H I ) : 25 t o 125 mg He's g TOC

Oxygen Index (01) : 50 t o 200 mg co2 g TOC

Average va lues o f these parameters a t a d e p t h o f 8000 f e e t where Ro i s

about 0.5 percen t produced t h e f o l 1 owl ng resu l t s :

H I : 165 mg HCts g TOC

01: 71 mg GO2

g TOC

The average H I f r o m t h e s e c u t t i n g s samples i s s l i g h t l y h i gh b u t i t i s f a r

less than t h e minimum value r e q u i r e d f o r an o i l - p r o n e f a c i e s (HI = 4 5 0 m R HCts f o r g TOC

" t ype B," o rgan i c f a c i e s , Demaison, 1981). Hydrocarbons formed i n a t y p e C

o rgan i c f a c i e s tend t o be gas prone, sometimes w i t h condensate. V isua l i n d e n t i -

f i c a t i o n o f t h e kerogen and r e l a t i v e l y h i g h P r / P h va lues (see F i g u r e 41) suppor t

t h i s hypo thes i s and suggest t h a t much o f t h e o rgan i c m a t t e r was d e r i v e d frorn

t e r r e s t r i a l sources.

Organic m a t t e r i s abundant th roughou t most o f t h e sed imentary s e c t i o n

encountered i n t h i s t e s t w e l l and i s e s p e c i a l l y h i g h i n c o a l - b e a r i n g i n t e r v a l s

between 3500 t o 4600 f e e t , 6400 t o 8600 f e e t , and 12,200 t o 14,400 f e e t .

S u f f i c i e n t thermal m a t u r i t y f o r peak o i l gene ra t i on e x i s t s be low 10,600

f e e t and c rude o i l c o u l d be p reserved t o a t l e a s t 14,000 f e e t . V i t r i n i t e

r e f l e c t a n c e , suppor ted by o t h e r i n d i c a t o r s o f thermal m a t u r i t y , suggests t h a t

d e p o s i t i o n o f sediment has been r e l a t i v e l y con t inuous t o a depth o f about

12,100 f e e t where a d i s t i n c t anornaly may rep resen t a h i a t u s i n sed imenta t ion

o f severa l thousand f e e t ,

M inor amounts o f gas and l i q u i d hydrocarbons a r e p resen t below 10,000 f e e t

assoc ia ted w i t h kerogen hav ing a moderate gene t i c p o t e n t i a l f o r hydrocarbon

genera t ion . The bes t s i gns of f r e e hydrocarbons p l u s o rgan i c e x t r a c t and s o l i d

b i tuminous m a t e r i a l f i 11 i n g f r a c t u r e s were observed i n conven t i ona l c o r e

number 9, between 12,200 and 12,250 f e e t .

A t depths g rea te r than 14,000 f e e t , o rgan i c carbon con ten t and abundance

o f sapropel i c kerogen a re 1 ow. Metamorphic rocks a r e p resen t i n a s i d e w a l l

c o r e a t 14,410 fee t . I t i s u n l i k e l y t h a t hydrocarbons have been generated a t

these depths a t t h i s l o c a t i o n ( f i g . 42).

ENVIRONMENTAL CONSIDERATIONS

By Paul Lowry

ARC0 E x p l o r a t i o n Company, as o p e r a t o r f o r i t s e l f and o t h e r

p a r t i c i p a n t s , s u b m i t t e d a l e t t e r da ted June 18, 1981, f o r t h e proposed

d r i l l i n g o f a Deep S t r a t i g r a p h i c T e s t we1 1 i n t h e N o r t o n Sound area o f t h e

A1 aska Ou te r C o n t i n e n t a l S h e l f , Documents i n suppor t o f t h i s p roposa l

i n c l u d e d a D r i 1 1 i n g Plan, an Env i ronmenta l Repor t , an O i 1 s p i 11 Con t ingency

P lan, and Coas ta l Zone C o n s i s t e n c y C e r t i f i c a t i o n . On t h e b a s i s o f

p r e l i m i n a r y i n f o r m a t i o n on t h e proposed l o c a t i o n s , a s i t e - s p e c i f i c

b i o l o g i c a l s u r v e y and a geohazards su rvey a t t h e p r i m a r y and a l t e r n a t e s i t e s

t o d e t a i 1 env i ronmenta l c o n d i t i o n s were r e q u i r e d b e f o r e approva l o f t h e

G e o l o g i c a l and Geophys ica l ( G & G ) P e r m i t app l i c a t i o n f o r t h e Deep

S t r a t i g r a p h i c T e s t w e l l . The a p p l i c a n t f o l l o w e d 30 CFR P a r t 251 i n

submiss ion o f t h e G&G P e r m i t f o r t h i s w e l l .

A Deep S t r a t i g r a p h i c Tes t we1 1 i s i n t e n d e d t o a c q u i r e q e o l o g i c a l and

e n g i n e e r i n g d a t a t o d e t e r m i n e t h e p o t e n t i a1 f o r h,ydrocarbon accumu la t ion

w i t h i n a proposed s a l e area. I t i s commonly d r i l l e d o f f s t r u c t u r e , and i t

i s n o t i n t e n d e d t h a t any hydrocarbon accumu la t ions be found. A l though t h e

r e v i s e d r e g u l a t i o n s dp n o t f o r b i d d r i l l i n g on s t r u c t u r e , t h e N o r t o n Sound

No. 2 well was d r i l l e d o f f s t r u c t u r e . The i n f o r m a t i o n aa the red f rom t h i s

t e s t w e l l was used t o f u r t h e r e v a l u a t e t h e hydrocarbon p o t e n t i a l o f OCS

Lease S a l e No. 57 ( N o r t o n B a s i n ) h e l d on March 15, 1983.

As p a r t o f t h e pe rm i t appl i c a t i on rev i ew process, an EnvS ronment a1

Assessment (EA) under t h e N a t i o n a l Env i ronmenta l P o l i c y Act (FIEPA) d i r e c t i v e

was prepared. An € A se rves as a dec is ion-making document t o determine i f

t h e proposed a c t i o n i s o r i s no t a ma jo r Federa l a c t i o n s i g n i f i c a n t l y

a f f e c t i n g t h e q u a l i t y of t h e human environment i n t h e sense o f NEPA, Sec t i on

1 0 2 ( 2 ) ( C ) . An E A addresses and i nc l udes t h e f o l l o w i n g : D e s c r i p t i o n o f t h e

proposed a c t ion, d e s c r i p t i o n o f t h e a f fec ted env i ronment, environment a1

consequences, a1 t e r n a t i v e s t o t h e proposed a c t i on , unavoidable adverse

environment a1 e f f e c t s , and c o n t r o v e r s i a1 i ssues .

On t h e b a s i s o f e x i s t i n g da ta and r e g u l a t i o n s i n e f f ec t a t t h e t i m e t h e

proposal was be ing reviewed, s p e c i f i c env i ronmenta l aspects were cons idered

MMS b e f o r e t h e d r i 11 i n g p l a n was approved.

Geo log i ca l Survey

A s i t e - s p e c i f i c sha l l o w d r i 1 1 i n g hazards su rvey (Nekton, 1980b),

r e q u i r e d by MMS, showed t h e s e a f l o o r a t t h e proposed s i t e s t o be near1.y

f l a t , w i t h e x t e n s i v e ev idence of sha l l ow i c e gouging. A t h i n veneer o f s o f t

Holocene c l a y e y s i l t and c l a y covered bo th s i t e s . C y c l i c l oad ing d u r i n g

s torm c o n d i t i o n s a ids t h e normal dynamic t i d a l c u r r e n t s i n resuspens ion and

t r a n s p o r t a t i o n of t h e upper severa l f ee t o f sediment. Th is leads t o

r e d e p o s i t i o n and, i n some cases, l i q u e f a c t i o n of the sea bottom. These

c o n d i t i o n s pe rm i t p e r i o d i c v e n t i n g of b i ogen i c gas t h a t m igh t form i n

pre-Holocene o r g a n i c - r i c h pea t y sediments. Video and s t i l l photoqraphs

taken i n c o n j u n c t i o n w i t h t h e b i o l o g i c a l surveys i n d i c a t e d t h a t t h e

subs t ra tum a t b o t h s i t e s was dominated by sand and s i l t , w i t h l i t t l e

c l a y and no g r a v e l . Sediment d i s t r i b u t i o n may be r e l a t e d t o t h e d i s t a n c e of

t h e s i t e s f rom t e r r e s t r i a l sediment sources and s t r o n g c u r r e n t s .

Geolog ic hazards:

1. Sha l low gas i n t h e v i c i n i t y of t h e o p e r a t i o n s i s r e s t r i c t e d t o

b i o g e n i c gas near t h e s u r f a c e . I t i s e a s i l y vented when t h e

sed iments are d i s t u r b e d and d i d n o t a f f e c t t h e d r i l l i n g

o p e r a t i o n s .

2. No s h a l l o w f a u l t s were p resen t a t t h e proposed s i t e .

3. S u r f i c i a1 sediments are s t a b l e , excep t f o r p o t e n t i a1 1 i q u e f a c t i o n

o f t h e t o p 1-2 m. T h i s d i d n o t i n t e r f e r e w i t h d r i l l i n g


4. Ice gouges i n t h i s area are v e r y s h a l l o w and d i d n o t a f f e c t


5. Sand waves and sediment scour caused by i n t e n s e c u r r e n t a c t i v i t y

d i d n o t occur a t t h e w e l l s i t e .

6. Permaf ros t was n o t encountered. Engi n e e r i nq procedures were

a v a i l a b l e t o c o n t r o l any d i f f i c u l t i e s t h a t m igh t a r i s e had

p e r m a f r o s t been encountered.

7. Abnormal p ressures and hydrogen s u l f i d e gas were no t expected o r

encountered.

Geolog ic hazards d i d no t impose undue r e s t r a i n t s on t h i s Deep

S t r a t i g r a p h i c Tes t we1 1 program.

M e t e o r o l o g i c a l and Oceanographic D a t a

Most o f t h e B e r i n g Sea l i e s i n s u b a r c t i c l a t i t u d e s and c y c l o n i c

atmospher ic c i r c u l a t i on predominates i n t h e r eg ion . Cloudy sk ies ,

modera te ly heavy p r e c i p i t a t i o n , and s t r o n g sur face winds c h a r a c t e r i z e t h e

mar ine weather. Storms a re more f r equen t i n t h e f a l l than i n t h e summer.

a There are two dominant c u r r e n t p a t t e r n s i n t h e Nor ton Sound area; t h e

nor thward f l o w i n g c u r r e n t s pass ing eas t o f S t . Lawrence I s l a n d and t h e

coun te r c l ockw i se c i r c u l a t i o n system w i t h i n No r t on Sound. Wave h e i g h t s

g r e a t e r than 8 f e e t are common less than 10 percen t of t h e t ime i n August

and September, and l e s s than 20 percen t of t h e t i m e i n October. A t Nome,

t h e mean dates o f sea- i ce breakup and freezeup are May 29 and November 12,

r e s p e c t i v e l y . Supe rs t r uc tu re i c i n g i s p o s s i b l e i n June and i s p robab le i n

October.

Sea i c e c o n d i t i o n s i n Nor ton Sound va ry f rom s i t e t o s i t e , and i c e

movement i s caused by a comb ina t ion of geography and p r e v a i l i n g n o r t h e a s t

w i n t e r winds. The p r e v a i l i n g no r t heas t winds r e s u l t i n an almost con t inuous

eas t -nor theas t t o west-southwest evacua t ion of i c e f rom t h e Sound th roughou t

• t h e w i n t e r . Except f o r t h e s h o r e f a s t i ce , t h e i c e i n t h i s area i s en t i r e1 , y

r ep laced by t h i s process seve ra l t imes d u r i n g a season. F i r s t - y e a r i c e

u s u a l l y moves ou t o f t h e area b,y t h e t ime i t i s about 18 inches t h i c k . The

s i t e i s c h a r a c t e r i z e d by r e l a t i v e l y t h i n , weak i c e i n cons tan t mot ion w i t h

e x t e n s i v e r a f t i n g .

Pack i c e g e n e r a l l y begins t o form i n Nor ton Sound i n mid- t o l a t e

October. Some areas i n and around t h e Sound a re comp le te l y i c e covered by

mid-November. A f t e r mid-December, pack i c e g e n e r a l l y comp le te ly covers t h e

Sound.

By mid-March t h e i c e pack a t t he head o f t h e Sound begins t o t h i n , b u t

does no t show app rec i ab le m e l t i n g u n t i l mid-May. By mid-June t h e Sound i s

comp le te l y i c e - f r e e . The No. 2 w e l l was d r i l l e d d u r i n g an open-water

season.

Because 1 i m i t e d meteor01 o g i c a l and oceanographic da ta were ava i 1 ab le ,

t h e MMS i ssued t h e Gu ide l i nes f o r C o l l e c t i o n o f Me teo ro l og i ca l ,

Oceanographic, and Performance Data (January 21, 1982) and r e q u i r e d t he

o p e r a t o r t o c o l l e c t me teo ro l og i ca l i n f o r m a t i o n t o a i d i n f u t u r e ope ra t i ons

w i t h i n Nor ton Sound. Dur ing setup and ope ra t i on , c l i m a t i c and sea s t a t e

c o n d i t i o n s were mon i to red t o ensure t h a t l o c a l c o n d i t i o n s d i d no t exceed r i g

t o l e r a n c e s o r j e o p a r d i z e human s a f e t y . Winds, ba rome t r i c pressure, a i r and

water temperatures, waves, cu r ren t s , and i c e c o n d i t i o n s were mon i to red . A l l

env i ronmenta l da ta c o l l e c t e d d u r i n g t h e d r i l l i n g o f t h i s w e l l are a v a i l a b l e

t o t h e p u b l i c (800 A S t ree t , Anchorage, A1 aska).

B i o l o g i c a l Surve,y

B i o l o g i c a l Su rvey R e s u l t s

A s i t e - s p e c i f i c m a r i n e b i o l o g i c a l s u r v e y was des igned b y MMS i n c o n c e r t

w i t h o t h e r F e d e r a l and S t a t e agenc ies t o p r o v i d e b i o l o g i c a l d a t a a t t h e

proposed Deep S t r a t i g r a p h i c T e s t s i t e s . Through t h e use o f underwa te r v i d e o

and p h o t o g r a p h i c documenta t ion , p l a n k t o n tows, i n f a u n a l sampl ing, and

t r a w l i n g ; A R C 0 (Nekton, 1980a) d e t e r m i n e d t h e r e l a t i v e abundance and t y p e s

o f organ isms p r e s e n t i n v a r i o u s h a b i t a t s . These s t u d i e s were conducted on

August 22-23, 1980, t o d e t e r m i n e b i o l o g i c a l r e s o u r c e s a t t h e proposed d r i l l

s i t e s . The r e s u l t s a r e summarized as f o l l o w s :

a 1. I n v e r t e b r a t e s were t he dominant component o f t r a w l ca tches , w i t h the

sea s t a r , A s t e r i a s amurensis, t h e most abundant t a x o n .

2. More f i s h were c o l l e c t e d a t t h e a l t e r n a t e s i t e than a t t h e p r i m a r y

s i t e , b u t t h e t o t a l w e i g h t o f f i s h was g r e a t e r a t t he p r i m a r y s i t e .

The s t a r r y f l o u n d e r , P l a t i c h t h y s s t e l 1 a tus , was t h e most abundant f l a t

f i s h a t the p r i m a r y s i t e . Few f l a t f i s h were t a k e n a t t h e a l t e r n a t e

s i t e . The s a f f r o n cod, E l e g i n u s c y a c i l i s , and t h e r a i n b o w smel t ,

Osmerus mordax dentex , were the most abundant round f i s h a t b o t h

s i t e s .

3. Demersal f i s h and e p i b e n t h i c i n v e r t e b r a t e s observed on v i d e o r e c o r d ingr ;

were s i m i l a r a t b o t h s i t e s . Sea s t a r s were t h e most numerous

i n v e r t e b r a t e s a t t h e a1 t e r n a t e s i t e . The e p i b e n t h o s and s u b s t r a t e

were s i m i l a r a t both s i t e s .

126

4, Taxanomic d i v e r s i t y and d e n s i t y were h i g h e r a t t h e a l t e r n a t e s i t e .

Po lychaete anne l i ds were n u m e r i c a l l y dominant a t bo th s i t e s , f o l l o w e d

by echinoderms, mo l luscs , and ar thropods.

5. The r e l a t i v e abundance, t o t a l number o f organisms per cub ic meter and

spec ies compos i t i on o f t h e p lank ton , was s i m i l a r a t t he two s i t e s .

Copepods were t h e most abundant p l a n k t o n i c organism at bo th s i des .

N e i t h e r s i t e suppor ted un ique h a b i t a t s o r spec ies o f spec ia l i n t e r e s t

t h a t r e q u i r e d r e j e c t i o n o r m o d i f i c a t i o n o f t h e No r ton Sound No. 2 w e l l

program. The Reg iona l Superv iso r , Offshore F i e l d Operat ions, conc luded t h a t

normal d r i l l i n g ope ra t i ons a t e i t h e r o f the two s i t e s would no t adve rse l y

a f f e c t t h e environment.

Mar ine MammalsIEndangered Species

Mar ine mammal d i s t r i b u t i o n i n t h e n o r t h e r n B e r i n g Sea and Nor ton Sound

i s s t r o n g l y i n f l uenced by t h e presence of sea i c e . Seasonal d i s t r i b u t i o n s

of severa l species, p a r t i c u l a r l y bowhead and be1 uga whales, walrus, and

r i nged , bearded, and s p o t t e d sea l s a re c l o s e l y assoc ia ted w i t h t h e advancing

and r e t r e a t i n g edge o f t he pack i ce . These spec ies w i n t e r i n t h e Nor ton

Sound-north Be r i ng Sea r e g i o n a t t h e sou thern l i m i t o f t h e pack i c e and

g e n e r a l l y f o l l o w i t s r e t r e a t nor thward d u r i n g summer. However, n o t a l l

i n d i v i d u a l s move n o r t h t o t h e Chukchi and Beau fo r t Seas a t t h a t t ime . A f e w

wal rus, spo t t ed and bearded seals , and he luqa and k i l l e r whales may s t i l l be

encountered i n No r t on Sound d u r i n g summer.

Severa l endangered whales ( t h e gray, bowhead, f i n , and humpback) a re

known t o occur i n t h e No r ton Sound area on a r e g u l a r o r an occas iona l b a s i s .

The endangered p e r e g r i n e f a l c o n occurs a long t h e coas t i n t h e Nor ton Sound

area. A fo rma l c o n s u l t a t i o n was reques ted f rom t h e N a t i o n a l Mar ine

F i s h e r i e s S e r v i c e (NMFS) pursuant t o Sec t i on 7 o f t h e Endangered Species Act

o f 1973, and a response p r o v i d i n g a nonjeopardy o p i n i o n was i ssued by NMFS

on A p r i l 28, 1981.

Us ing t h e i n f o r m a t i o n rece i ved f rom a l l i n t e r e s t e d p a r t i e s , as we1 1 as

our own in-house eva lua t i on , i t was determined t h a t approval o f t h e proposed

a c t i o n would no t a f f e c t an endangered spec ies o r i t s c r i t i c a l h a b i t a t .

F i s h e r i es

The mar ine f i s h e r y o f Nor ton Sound i s no t as p r o d u c t i v e as t h a t i n

other p o r t i o n s o f the Ber ing Sea; however, t h e r e i s a limited comrnerci a1

u t i l i z a t i o n o f l o c a l she l l f i s h and demersal f i s h . Most abundant demersal

f i s h i n c l u d e cod, f l a t f i s h , s cu lp i ns , h e r r i n g , and sme l t . Shrimp, k i n g and

Tanner crab, and c l ams dominate t h e shel lf i sh resources.

B i r d s

The Nor ton Sound av i f auna i s dominated b,y t h e summer water fowl and

s h o r e b i r d presence a t t h e Yukon D e l t a . T h i s area i s recogn ized as one o f

t h e most p r o d u c t i v e n e s t i n g areas i n Alaska. Est imates o f summer

p o p u l a t i o n s i n c l u d e 3 m i l l i o n wa te r fow l and over 100 m i l l i o n sho reb i r ds ; 170

d i f f e r e n t spec ies have been recorded. Coasta l s a l t marshes, which are the

key t o t h i s a rea ' s p r o d u c t i v i t y , p r o v i d e n e s t i n g h a b i t a t f o r b i r d s such as

b l a c k b ran t , emperor, c a c k l i n g , and w h i t e - f r o n t e d geese; common, spectac led,

and S t e l l a r ' s e i d e r s ; w h i s t l i n g swans; and numerous ducks and sho reb i r ds .

These b i r d s have a s t r o n g a f f i n i t y f o r c o a s t a l h a b i t a t s and do no t t y p i c a l l y

occur more than 2 t o 3 m i l e s o f f shore , except d u r i n g m i g r a t i o n s .

Nor ton Sound a l so suppor ts severa l mar ine b i r d r ooke r i es , a1 though t h e

number o f c o l o n i e s and t h e i r i n d i v i d u a l s i z e s (number o f b i r d s ) do n o t

compare w i t h those i n o t h e r B e r i n q Sea reg ions . Murres, k i t t i w a k e s ,

cormorants, and p u f f i n s a re most common.

C u l t u r a l Resources

a C u l t u r a l r esou rce surveys may be r e q u i r e d i n o rde r t o assure t h a t no

d i s t u r b a n c e o f a r c h e o l o g i c a l o r c u l t u r a l resources on t h e seaf l o o r . A f t e r

consul t a t i o n w i t h t h e resource agencies, MMS determined t h a t such surveys

would no t be r e q u i r e d f o r t h e Nor ton Sound w e l l s i t e s as t hey were l oca ted

i n low-probabi 1 i ty areas f o r c u l t u r a l resources , I f t h e TV t r a n s e c t s and

s ide-scan sonar taken i n c o n j u n c t i o n w i t h t h e b i o l o g i c a l survey had

i n d i c a t e d unexpl a ined anomal ies , a r ev i ew by a qua1 i f i e d mar ine a r c h e o l o g i s t

would have been r e q u i r e d . No such anomalies were detected. No c u l t u r a l

resources were i d e n t i f i e d d u r i n g d r i l l i n g ope ra t i ons .

D ischarges i n t o t h e Mar ine Environment

Some l i q u i d wastes, i n c l u d i n g o i l f rom t h e o i l l w a t e r separa to r , were

t r a n s p o r t e d f r o m t h e d r i l l i n g vesse l by supp ly boa ts and d isposed o f i n

approved onshore 1 oca t i ons. Sol i d wastes were compacted and s i m i 1 a r l y

t r a n s p o r t e d t o an approved onshore d i sposa l s i t e . L i q u i d wastes, i n c l u d i n g

t r e a t e d sewage, g r a y water, and some d r i l l i n g by-products , were d ischarged

on s i t e i n t o mar ine waters i n accordance w i t h r e g u l a t i o n s se t f o r t h by t h e

U.S. Env i ronmenta l P r o t e c t i o n Agency ( E P A ) .

The a p p l i c a n t d isposed o f d r i l l c u t t i n g s and waste d r i l l i n q mud i n t o

t h e ocean i n compl iance w i t h e x i s t i n g o rde rs . No o i l - b a s e d mud was used.

B e n t o n i t e i s a con t inuous a d d i t i v e t o t h e d r i l l i n g mud, whereas b a r i t e i s

added as necessary f o r i n c r e a s i n g mud we igh t . B e n t o n i t e and b a r i t e a re

i n s o l u b l e , non tox i c , and i n e r t . Other a d d i t i v e s are used i n minor

concen t ra t i ons , and most a re used o n l y under s p e c i a l c o n d i t i o n s . These

o t h e r a d d i t i v e s are e i t h e r non tox i c , o r would c h e m i c a l l y n e u t r a l i z e i n t h e

mud o r upon c o n t a c t w i t h seawater ( i . e . , c a u s t i c soda). Excess cement

en te red and was d ispersed i n t o t he ocean when t h e sha l l ow cas ing s t r i n g s

were s e t .

Past s t u d i e s on t h e f a t e and e f f e c t s o f r o u t i n e d ischarges f rom

o f f s h o r e o i l and gas a c t i v i t i e s i n t o t h e mar ine environment and t h e known

d i s p e r s i o n r a t e s o f such d ischarges, show t h a t such ope ra t i ons do no t

s i g n i f i c a n t l y a f f e c t t h e environment.

Cont inqency P lans f o r O i l s p i l l s

P lans f o r p reven t i ng , r e p o r t i n g , and c l e a n i n g up o i l s p i l l s were

addressed i n t h e O i l s p i l l Cont ingency P l a n (OSCP), which was a p a r t o f t h e

d r i l l i n g p lan , The OSCP l i s t e d the equipment and m a t e r i a1 a v a i l a b l e t o t h e

p e r m i t t e e and desc r i bed t h e c a p a b i l i t i e s o f such equipment under d i f f e r e n t

sea and weather c o n d i t i o n s . The p l a n a l s o i n c l u d e d a d i scuss ion o f

l o g i s t i c a l suppor t programs f o r con t ingency ope ra t i ons . The p r o b a b i l i t y of

encoun te r ing hydrocarbons t h a t cou ld cause a b lowout a t any depth was

m in im ized i n t h i s case b,y l o c a t i n g t h e w e l l o f f s t r u c t u r e . The ope ra to r

d r i l l e d t h e w e l l accord ing t o t h e OCS Orders and used s tandard w e l l c o n t r o l

equipment and procedures. The cas ing and cement ing programs and subsequent

abandonment r equ i r emen ts ( as o u t 1 i ned i n OCS Order No. 3 ) were designed t o

p reven t leakage o r con tamina t ion o f f l u i d s w i t h i n a permeable zone.

Upon comple t ion of t h e w e l l , t h e s i t e was c l e a r e d of a l l p i n e and o t h e r

rna te r i a \ on or above the ocean f l o o r .

a As a p a r t o f t h e E A process, t h e proposed program was submi t ted t o t h e

a p p r o p r i a t e Federa l and S t a t e agencies, as w e l l as i n t e r e s t e d p a r t i e s , f o r

comments. Responses were i nc l uded as p a r t of t h e E A , On t h e b a s i s o f €A

No. AK-81-5, i t was determined, on October 26, 1981, t h a t ARCO's proposed

a c t i o n c o n s t i t u t e d a f i n d i n q o f no g n i f i c a n t impact (FONSI), ancl an

Env i ronmenta l Impact Statement was no t r e q u i r e d . A N o t i c e was i s s u e d t o

t h a t e f f e c t . MMS consequen t l y i ssued a l e t t e r t o ARCO, da ted January 21,

1982, approv ing t h e i r proposed a c t i o n . The EA and t h e F O N S I documents a re

i n t h e p u b l i c f i l e i n t h e o f f i c e of the Reg iona l Supervisor, Offshore F i e l d

Operat ions, 800 A S t ree t , Anchorage, Alaska, 99501.

SUMMARY AND CONCLUSIONS

By Ronald F. Turner

P r i o r t o t h e comp le t i on o f t h e Nor ton Sound Deep S t r a t i g r a p h i c Tes t w e l l

program, ve ry l i t t l e was known about t h e pe t ro l eum p o t e n t i a l o f t h i s OCS f r o n t i e r

area. The most w i d e l y accepted b a s i n e v o l u t i o n model was t h e comprehensive

a n a l y s i s o f F i s h e r and o t h e r s (1982). S ince t h e comp le t i on o f t h e second and

f i n a l t e s t w e l l , however, t h e number o f models has appa ren t l y i nc reased t o near

t h a t o f t h e number o f p a r t i c i p a n t s . Wi th t h e p u b l i c r e l e a s e of t hese da ta , i t

i s a lmost c e r t a i n t h e number w i l l i n c rease again. Bas in e v o l u t i o n models based on

subsur face g e o l o g i c a l , geophys ica l , and geochemical da ta a r e doub ly i n t e r p r e t i v e

owing t o t h e very n a t u r e o f t h e data. T h i s i n t e r p r e t a t i o n i s no excep t ion .

@ It i s , however, t h e f i r s t pub l i shed i n t e r p r e t a t i o n made w i t h t h e b e n e f i t o f

w e l l data. A l though t ime c o n s t r a i n t s imposed by s t a t u t o r y da ta r e l e a s e dates

have, t o some e x t e n t , 1 i m i t e d v a r i o u s aspec ts o f t h i s ongoing i n v e s t i g a t i o n ,

i t i s s u b s t a n t i a l l y complete. P r e l i m i n a r y a n a l y s i s o f t h e d a t a f rom t h e two

w e l l s suggests a b a s i n e v o l u t i o n t h a t d i f f e r s f rom t h e p r e d i c t e d models i n

severa l aspec ts o f d e p o s i t i o n a l and subsidence h i s t o r y . I n genera l , t h e b a s i n

f i l l i s younger and f a r more mar ine than had been a n t i c i p a t e d , and t h e t ec tono -

e u s t a t i c h i s t o r y o f t h e b a s i n i s more complex.

The sedimentary b a s i n f i l l appears t o be younger t han p rev i ous es t imates .

The presence of Cretaceous sedimentary r ocks and coa l a long the eas te rn shore

o f Nor ton Sound (Pa t ton , 1973) l e d F i s h e r and o t h e r s (1982) t o p o s t u l a t e t h a t

t h e Nor ton Bas in m igh t c o n t a i n sed imentary r ocks as o l d as L a t e Cretaceous. a

However, t h e m idd le t o l a t e Eocene s t r a t a p resen t i n t h e No. 2 we1 1 (10,160-12,700

f e e t ) a r e t h e o l d e s t sediments f o r which we have a firm age. Th i s d e f i n i t e

Eocene s e c t i o n i s u n d e r l a i n by a 1760 f o o t t h i c k sequence o f i n t e rbedded sandstone,

s i l t s t o n e , mudstone, and coa l depos i t ed under f l u v i a l and pa luda l c o n d i t i o n s .

Eocene fungal palynomorphs were recovered f rorn s i d e w a l l co res t aken i n t h i s

s e c t i o n bu t n o t f r om conven t iona l cores. The p r e s e r v a t i o n a l s t a t e o f these

palynomorphs matched t h a t of i n s i t u elements o f t h e sparse and p o o r l y p reserved

spo re -po l l en assemblage. Because of t h e somewhat equ ivoca l n a t u r e o f t h e

ev idence, t h i s sec t i on , and a much t h i n n e r c o r r e l a t i v e s e c t i o n i n t h e No. 1

w e l l (12,235-12,545 f e e t ) , was ass igned an age o f Eocene o r o l de r . In b o t h

No r ton Sound we1 1 s these s t r a t a unconformably over1 i e much 01 de r metamorphic

basement rocks. On t h e b a s i s of t h e p resen t data, i t appears l i k e l y t h a t t h e y

r ep resen t t h e o l d e s t sedimentary r ocks i n t he b a s i n and a r e no o l d e r than

@ Pal eocene, p robab l y younger.

Another l e s s d i r e c t l i n e of ev idence a l s o suppor ts an e a r l y T e r t i a r y age

f o r t hese sediments. The metamorphic t e r r a n e s o f t h e Seward Pen insu la a re t h e

source o f much o f t h e sediment i n t h e Nor ton bas in , p a r t i c u l a r l y t h e S t . Lawrence

subbasin. A potassium-argon da te f rom a muscov i te concen t ra te f rom one o f t h e

l owe r~nos t sandstones i n t h e No. 1 w e l l (12,398 f e e t , Eocene o r o l d e r s e c t i o n )

y i e l d e d an age o f approx imate ly 146 m.y. T h i s da te r ep resen t s t h e L a t e J u r a s s i c

t o E a r l y Cretaceous metamorphism of t h e source t e r r a n e and i s i n agreement w i t h

potassium-argon ages ob ta i ned f r om w h i t e micas f rom b l u e s c h i s t - f a c i e s metamorphic

r ocks from t h e Seward Pen insu la (A. T i 1 1, personal communicat ion). I s o l a t e d

glaucophane-bear ing rocks have l o n g been known f r om t h e Seward Pen insu la (Smith,

1910; Sainsbury and o the rs , 1978), b u t more r e c e n t l y Forbes and o t h e r s (1981 ) ,

and T i 11 (1982) desc r i bed an e x t e n s i v e h igh- tempera tu re b l u e s c h i s t - f a c i e s

t e r r a n e there . These rocks a r e though t t o have formed a t 8-10 kb p ressu re a t

c r u s t a l depths o f a t l e a s t 24 km (A, T i l l , personal communicat ion). I n t h e

1 a t e Cretaceous (68-69 rn.y., K-Ar da te ) , t hese rocks were i n t r u d e d by ep izona l

g r a n i t e s t ocks ( t h e " t i n g r a n i t e s " ) a t depths o f perhaps 9 km (Hudson, 1979).

The o v e r a l l t h i c k n e s s o f t h e b l u e s c h i s t rocks cannot be asce r t a i ned , n o r can t h e

amount o f s e c t i o n removed a t o r b e f o r e t h e t i m e o f g r a n i t e implacement. Even

so, i t seems u n l i k e l y t h a t micaceous rocks t h a t r e c r y s t a l i z e d a t b l u e s c h i s t -

f a c i e s depths i n t h e L a t e J u r a s s i c - E a r l y Cretaceous and were l a t e r i n t r u d e d i n

t h e L a t e Cretaceous w h i l c s t i l l a t g r e a t depth, would be a v a i l a b l e as sed imentary

b a s i n f i l l i n t h e L a t e Cretaceous. I n f a c t , i t appears t h a t t h e basal uncon fo rm i t y

and t h e onset o f basement r i f t i n g b o t h may rep resen t e a r l y T e r t i a r y events.

The S t . Lawrence and S t u a r t subbasins r e s u l t e d f rom m u l t i p h a s i c ex tens iona l

t e c t o n i s m expressed a s d i f f e r e n t i a l , nonsynchronous subsidence a l ong normal

f a u l t s . There appear t o be s i g n i f i c a n t i n t r a - f i l l uncon fo r l n i t i e s p resen t i n

b o t h subbasins. L i t h o l o g i c , d i pmeter, geophys ica l , and geochemical ev idence

f o r t h e l owes t uncon fo rmi ty i s bes t developed i n t h e No. 2 we1 1. Th i s s u r f a c e

may have formed contemporaneously w i t h o r preceded i n i t i a l up1 i f t i n g o f t h e

ho rs t . The ambiguous evidence f o r a n g u l a r i t y seen on one n o n p r o p r i e t a r y se ismic

l i n e suggests t h a t t h e unconformi t y was i n p a r t t e c t o n i c a l l y c o n t r o l l e d .

E u r t a t i c changes t h a t r e s u l t e d i n l owe r base l e v e l may be invoked as an a l t e r n a t i v e

o r a n c i l l a r y t o tec ton ism. C a l c u l a t i o n s made f rom v i t r i n i t e r e f 1 ectance va lues

( f o l l o w i n g t h e method o f DOW, 1977) suggest t h a t perhaps 1000 fee t of s e c t i o n

may be m i s s i n g i n t h e No. 2 w e l l . A more s u b t l e m a t u r i t y anomaly o f l e s s

magnitude i s p resen t i n t h e No. 1 w e l l f o r which no m i s s i n g s e c t i o n c o u l d be

c a l c u l a t e d . If t h i s l o w e r uncon fo rm i t y separates e a r l y and m idd le Eocene

rocks , t h e e r o s i o n was r e l a t i v e l y rap id . The uncon fo rm i t y c o u l d a l s o be i n t e r p r e t e d

as a mar ine t r a n s g r e s s i v e event , if t h e d e p o s i t i o n a l n a t u r e o f t h e Ol igocene o r

o l d e r s e c t i o n o f t h e No. 1 we1 1 was l e s s equ ivoca l and t h e p o s i t i o n o f t h e

uncon fo rm i t y i n t h e No. 2 well was moved up t o t h e mar ine i n t e r v a l a t 12,200

f e e t ( t h e b e s t geochemical f i t , r a t h e r than t h e 12,700 f e e t d ipmete r p i c k ) ,

Samples and o t h e r da ta f ro in t h i s i n t e r v a l i n b o t h w e l l s a r e be ing reprocessed

and reeva lua ted i n hopes o f c l e a r i n g up these amb igu i t i e s . As ide f r om t h e

ma jo r uncon fo rm i t y between Pa leozo ic and Cenozoic rocks, and t h e mid-Eocene

( ? ) uncon fo rm i t y d iscussed above, two o t h e r u n c o n f o r m i t i e s were i d e n t i f i e d , a

P l i o-Pl e i s tocene unconformi ty d i s c e r n i b l e on s h a l l ow se ismic 1 i nes and a m i d-

Miocene h i a t u s based on s i l i c e o u s rn i c ro foss i l s .

Perhaps t h e most i n t r i g u i n g d e v i a t i o n f rom t h e p r e d i c t e d b a s i n model

concerns t h e n a t u r e of Paleogene depos i t i on . On t h e b a s i s o f s c a t t e r e d ou tc rops

o f non~nar ine Paleogene rocks around Nor ton Sound, t h e presumed nonmarine n a t u r e

o f sediments o f t h i s presumed age i n t h e Hope bas in , and re fe rence t o t h e Anadyr

b a s i n as an analog, F i s h e r and o the rs (1982) specu la ted t h a t t h e Paleogene

s e c t i o n o f t h e Piorton b a s i n con ta i ned o n l y nonmarine rocks. I n f a c t , b o t h

w e l l s c o n t a i n s i g n i f i c a n t t h i c knesses o f Paleogene age mar ine s t r a t a . I f , as

p o s t u l a t e d by Herman and Hopkins (1980), t h e B e r i n g Sea l a n d b r i d g e separa ted

t h e P a c i f i c and A r c t i c oceans u n t i l 3.5 m.y. age, t h i s Paleogene mar ine connec t ion

was p robab ly an arm o f t h e P a c i f i c , and t h e Nunivak a rch o f Scho l l and Hopkins

(1969) and Marlow and o t h e r s (1976) was n o t t h e b a r r i e r t o Pal eogene mar ine

i n c u r s i o n s p o s t u l a t e d by F i s h e r and o t h e r s (1 982). A l t e r n a t i v e l y , t h e

seaway between t h e eastward moving S i b e r i a n b l o c k ( t h e Chuktosk and Seward

pen insu las ) and main land Alaska inay n o t have been e n t i r e l y c l o s e d a t t h e end o f

t h e Cretaceous as p o s t u l a t e d by Sachs and S t r e l kov (1961 ) and Holmes and Creager

1981). I t i s a l s o conce i vab le t h a t an A r c t i c connec t i on c o u l d have been

r e e s t a h l i shed th rough 1 ows ove r t h e Seward Pen insu la be fo re ma jo r 1 a t e Cenozoic

up1 i f t s . The presence o f Pal eogene f o r a m i n i f e r a 1 faunas w i t h s t r o n g a f f i n i t i e s

t o those of Sakha l i n I s l a n d and t h e Kamchatka Pen insu la suppor ts a P a c i f i c

r a t h e r t h a n A r c t i c connect ion. I n p a r t i c u l a r , t h e presence of spec ies o f

Po roso ro ta l i a, a predomi n a n t l y a u s t r a l Paci f i c Pal eogene forami n i f e r a l genus,

l ends f u r t h e r credence t o t h i s i n t e r p r e t a t i o n .

O f t h e two w e l l s , t h e No. 1 i s by f a r t h e most mar ine i n aspect. Nea r l y

5000 f e e t o f t h e 5197 f o o t t h i c k Ol igocene s e c t i o n was depos i t ed i n o u t e r

n e r i t i c t o upper ba thya l depths. I f t h e apparent t u r b i d i t e s below i t ( t e n t a t i v e l y

c o r r e l a t e d w i t h t h e m idd le t o l a t e Eocene s e c t i o n i n t h e No. 2 w e l l ) a r e a l s o

marine, t h e n v i r t u a l l y t h e e n t i r e Pal eogene s e c t i o n , w i t h t h e excep t i on o f 31 0

f e e t o f c o a l - b e a r i n g sediments o f p o s s i b l e Eocene o r o l d e r age, i s marine.

More t han h a l f o f t h e 6536 f o o t Ol igocene s e c t i o n i n t h e No. 2 w e l l i s made up

o f she1 f a 1 mar ine sediments; t h e remainder c o n s i s t s of c o a l - bea r i ng t r a n s i t i o n a l

sediments depos i t ed i n marsh and e s t u r i n e env i ronments under mar ine i n f l uences.

The Eocene s e c t i o n a l s o r e f l e c t s s i g n i f i c a n t t r a n s i t i o n a l c o n d i t i o n s , and

d e f i n i t e mar ine f o s s i l s a r e p resen t as deep as 11,200 f e e t . A l l i n a l l , t h e r e

i s p robab l y 1 ess t h a n 2400 f e e t cumu la t i ve t h i c k n e s s of p u r e l y c o n t i n e n t a l

Paleogene s e c t i o n p resen t i n t h e No. 2 w e l l . The l a t e Ol igocene coa l - bea r i ng

sequence desc r i bed i n b o t h w e l l s ( o u r O se ismic h o r i z o n ) i s i n p a r t c o r r e l a t i v e

w i t h coa l s o f t h e same age r e p o r t e d f rom near U n a l a k l e e t (Pa t ton , 1973; W.

Pat ton, w r i t t e n communicat ion) and f rom St. Lawrence I s 1 and by Cse j t ey and

P a t t o n (1974). These s t r a t a appear t o d e f i n e a r e g i o n a l r e g r e s s i v e event t h a t

may have con t i nued i n t o the e a r l i e s t Miocene.

The Yukon h o r s t does no t appear t o have been a ma jo r b a r r i e r between t h e

two subbasins u n t i l a f t e r t h e mid-Eocene ( ? ) e r o s i o n a l event w i t h which i t may

be c a u s a l l y r e l a t e d . T h e r e a f t e r t h e subbasins had somewhat d i f f e r e n t t e c t o n i c

and d e p o s i t i o n a l h i s t o r i e s u n t i l t h e mid-01 igocene t r a n s g r e s s i v e event t h a t

breached t h e e l onga te no r t h - sou th s t r u c t u r e . Subsidence a f t e r t h i s t i m e appears

t o have been a bas in -w ide i s o s t a t i c reponse t o sediment l oad ing , and f o r t h e

f i r s t t i m e d e p o s i t i o n extended beyond t h e independent, s t r u c t u r a l l y d e l i n e a t e d

subbasins. A l though d e p o s i t i o n i n t h e St. Lawrence subbas in (No. 1 w e l l ) was

@ always more mar ine than i n t h e more e a s t e r l y s i t u a t e d S t u a r t subbasin, t h e

Yukon h o r s t was n o t an a l t o g e t h e r e f f e c t i v e p h y s i c a l o r f auna l b a r r i e r as

evidenced by t h e presence o f f o s s i l i fe rous mar ine s t r i n g e r s i n t e r c a l a t e d w i t h

c o n t i n e n t a l and t r a n s i t i o n a l c o a l s th roughou t t h e Eocene and Ol igocene s e c t i o n

o f t h e No. 2 w e l l .

The most d i f f i c u l t equivalency t o e s t a b l i s h i s t h a t between the problematic

01 igocene o r o l d e r n o n f o s s i l i f e r o u s t u r b i d i t e s ( ? ) o f t h e No. 1 w e l l and t h e

m i d d l e t o l a t e Eocene t r a n s i t i o n a l t o c o n t i n e n t a l coa l - bea r i ng s e c t i o n o f t h e

No. 2 we1 1 (as was no ted i n t h e d i s c u s s i o n o f t h e uncon fo r ln i t y a t t h e base of

bo th ) . Small c h i p s o f unweathered glaucophane s c h i s t i n c u t t i n g s f rom t h i s

s e c t i o n o f t h e No. 1 w e l l i n d i c a t e r a p i d e r o s i o n f r om a nearby source, p robab l y

a t h e ho rs t . I f these w e l l s e c t i o n s a r e c o r r e l a t i v e , as we now b e l i e v e , t hen t h e

presence of Eocene mar ine f o s s i l s i n t h e No. 2 w e l l makes a l a c u s t r i n e o r i g i n

f o r t h e t u r b i d i t e s e c t i o n o f t h e No, 1 w e l l (9690-12,235 f e e t ) d i f f i c u l t t o

e x p l a i n i n terms o f simp1 e pa l eogeography. Geochemical ev idence f o r a l a c u s t r i n e

env i ronn~ent i s n o t compel 1 i ng . The dominant o rgan i c m a t e r i a l p resen t ove r t h e

i n t e r v a l i s t ype I I 1 kerogen assoc ia ted w i t h m inor amounts o f p o s s i b l e t y p e I 1

kerogen. Type I kerogen, e s p e c i a l l y a l g a n i t e , i s t h e t y p e of o rgan i c m a t e r i a l

c h a r a c t e r i s t i c o f 1 arge l a c u s t r i n e d e p o s i t i o n a l systems. Only one sarnpl e ( f r o m

a conven t i ona l c o r e a t 9758 f e e t ) y i e l d e d an a n a l y s i s t h a t m igh t r ep resen t

t y p e I kerogen.

On t h e b a s i s o f source, m a t u r i t y , s t r u c t u r e , and p o t e n t i a l r e s e r v o i r s , t h e

Paleogene s e c t i o n o f t h e Nor ton b a s i n i s t h e most p r o s p e c t i v e f o r petroleum.

@ The Neogene s e c t i o n pene t ra ted by t h e two t e s t w e l l s conformed r a t h e r w e l l t o

expec ta t i ons o f t h i c kness , cha rac te r , and hydrocarbon p o t e n t i a l . Perhaps a

t h i c k e r Miocene s e c t i o n elsewhere i n t h e b a s i n m igh t have more p o t e n t i a l . A t

f i r s t g lance i t would appear t h a t t h e Pa leozo ic s e c t i o n c o n s i s t s of nonprospec t i ve

metamorphics. No th ing seen i n e i t h e r w e l l s t r o n g l y c o n t r a d i c t s t h a t nega t i ve

assessment. However, minor amounts o f marb le were co red i n t h e l owe r p a r t o f

t h e No. 2 w e l l , and a t h i c k sequence of Pa leozo ic carbonates i s p resen t on t h e

Seward Peninsu la . I t i s p o s s i b l e t h a t p o t e n t i a l Pa leozo ic ca rbona te r e s e r v o i r s ,

perhaps enhanced by pre-mid-01 i gocene k a r s t i ng, a r e p resen t on t h e h o r s t . The

c a t a c l a s t i c a l l y sheared s l a t e and marb le seen i n t h e No. 1 w e l l m igh t a l s o

develop r e s e r v o i r qua1 i t i e s i n some s e t t i n g s . A much more thorough unders tand i ng

o f t h e age and s t r u c t u r a l r e l a t i o n s h i p s o f t h e r ocks of t h e basement complex i s

necessary be fo re i t s p o t e n t i a l as an e x p l o r a t i o n p l a y can be addressed. A l though

t h e p a t t e r n observed on t h e Seward Pen insu la by Sainsbury and o t h e r s (1970) o f

i n c r e a s i n g metamorphic grade eastward appears t o h o l d i n t h e Nor ton Sound w e l l s ,

i t may be more pe rce i ved than r e a l . S tud ies on t hese rocks c u r r e n t l y underway

shou ld he1 p e l u c i d a t e t h e complex geo log i c h i s t o r y o f t h e nearby Seward

Pen insu la , and t hus t h e e v o l u t i o n o f t h e Nor ton Basin.

ARCO Nor ton Sound COST No. 2 Summary

The ARCO Nor ton Sound COST No. 2 w e l l was d r i l l e d t o a measured depth o f

14,889 f e e t . The KB was 105 f e e t above sea 1 eve1 and 154 f e e t above mud1 i ne .

The wa te r dep th was 49 f e e t . D r i l l i n g coinmenced on June 7, 1982 and was completed

i n 81 days on August 27, 1982. D r i l l i n g r a t e s ranged f r om 3 t o 250 feet /hour .

Four s t r i n g s o f cas i ng were s e t : 30 i n c h a t 416 f e e t , 20 i n c h a t 1181 f e e t ,

13 3/8 i n c h a t 4673 f e e t , and 9 5/8 i n c h a t 11,862 f ee t . The d r i l l i n g f l u i d

progrdm was: sea wa te r t o 1231 f e e t , 9 pounds/gal l o n l i g n o s u l f a t e rnud t o 5100

f e e t , 1 0 pounds/ga l lon t o 11,100 f e e t , 12 pounds /ga l lon t o 14,889 f e e t . Gas

assoc ia ted w i t h coa l beds was encountered f rom 12,212 t o 13,717 fee t ,

T h i r t e e n conven t i ona l cores, 499 s i d e w a l l co res , and many w e l l c u t t i n g

samples were analyzed f o r p o r o s i t y , p e r m e a b i l i t y , l i t h o l o g y , hydrocarbon con ten t ,

and pa leon to logy . Ro ta ry d r i l l b i t c u t t i n g s were c o l l e c t e d f rom 450 t o 14,889

f e e t .

• Logging runs were made a t depths o f 4700, 11,907, and 14,889 f e e t . The

Dual I nduc t i on -La te r01 og (D IL ) , Borehol e Compensated Sonic Log (BHC) , and

Spontaneous P o t e n t i a l (SP), Gamma Ray ( G R ) , Long Spaced Sonic Log (LSS) w i t h

I n t e g r a t e d T rave l Time ( I T T ) , Repeat Format i on Tes t (RFT) , and t h e Four-arm,

High R e s o l u t i o n Cont inuous Dipmeter (HRD), were recorded on a l l runs. The

Compensated Neutron Log (CNL) w i t h Neutron Gamma Tool (NGT) were recorded on

t h e f i r s t and second runs. On t h e second and t h i r d runs a V e r t i c a l Seismic

P r o f i l e (VSP), L i t h o d e n s i t y Neutron Log and P r o x i m i t y Log-Mic ro log (MPL) were

recorded. A d d i t i o n a l 1 ogs run were a Compensated Format ion D e n s i t y Log (FDC)

and a V e l o c i t y Survey, on t h e f i r s t run; and a Cement Bond Log (CBL) and

Temperature Log on t h e l a s t run. A Gamma Ray Casing C o l l a r L o c a t o r was run a t

11,651 f e e t .

Two d r i l l stem t e s t s f o r wa te r a n a l y s i s were made th rough p e r f o r a t i o n s i n

t h e 9 518 i n c h cas ing.

The cumu la t i ve c o s t f o r t h e w e l l was $32.2 m i l l i o n .

As r e q u i r e d by 30 CFR 251, t h e o p e r a t o r (ARCO) f i l e d a D r i l l i n g Plan,

Env i ronmentdl Ana l ys i s , O i l s p i l l Cont ingency Pl an, and Coasta l Zone Management

C e r t i f i c a t i o n . I n a d d i t i o n , geohazards, geo techn i ca l , and s i t e - s p e c i f i c b i o l o g i c a l

surveys were requ i r ed . The zooplankton, i n f auna , ep i fauna , v a g i l e benthos,

and pe l a g i c fauna were c o l 1 ec ted and analyzed. P a r t i c u l a r emphasis was p l aced

on p r o t e c t i n g 1 oca l and m i g r a t o r y mar ine mammal s and a v i fauna. Waste d ischarges

i n t o t h e environment were min imal , non tox i c , and i n compl i ance w i t h Federa l

env i ronmental p r o t e c t i o n regu l r t i o n s .

S t r a t i g r a p h i c u n i t s i n t h e No. 2 w e l l were de f i ned on t h e b a s i s of

m i c r o f o s s i l con ten t , 1 i tho1 o g i c a l and 1 og c h a r a c t e r i s t i c s , c o r r e l a t i o n w i t h t h e

No. 1 w e l l , and se ismic cha rac te r , S t r a t a pene t ra ted were P l e i s t o c e n e f rom 450

t o 1320 f e e t , P l i ocene f rom 1320 t o 2580 f e e t , Miocene f r om 2580 t o 3524 f e e t ,

Ol igocene f rom 3524 t o 10,160 f e e t , Eocene f rom 10,160 t o 12,700 f e e t , Eocene

o r o l d e r f rom 12,700 t o 14,460 f e e t , and p robab le Pa leozo ic f rom 14,460 t o

14,889 f e e t .

Sample q u a l i t y and recovery was poor i n much o f t h e P l e i s t o c e n e s e c t i o n

and c o n s i s t e d of f i n e t o medium gra ined , unconso l i da ted s h e l l y sand w i t h abundant

l i t h i c f ragments and o rgan ic deb r i s . The P l i ocene s e c t i o n i s c h a r a c t e r i z e d by

s i l t s t o n e , muddy sandstone, and diatomaceous mudstone. The Miocene s e c t i o n

c o n s i s t s o f diatomaceous mudstones, s i l t s t o n e , and muddy sandstones. The

3 l i gocene i s coa l - bea r i ng ove r most of t h e sec t i on . The coa l a t t h e t o p o f

t h e s e c t i o n (3535-4570 f e e t ) i s c o n t i n e n t a l ( f l u v i a l and pa l uda l ) , t h a t below

6300 f e e t i s more e s t u r i n e and d e l t a i c i n aspect. Sandstone and s i l t s t o n e a re

rnore common i n t h e deeper mar ine i n t e r v a l s (4570-6900 f e e t ; 8000-8500 f e e t ) .

The Eocene s e c t i o n i s t r a n s i s t i o n a l t o i n n e r n e r i t i c f rom 10,160 t o 12,200

f e e t and i s c h a r a c t e r i z e d by sandstone, s i l t s t o n e , mudstone, and shale . Coal

i s p resen t i n many samples and may rep resen t e i t h e r c a v i n g o r p a r t i n g s as no

coal beds were cored o r seen on e l e c t r i c logs . The lower p a r t o f t h e i n t e r v a l

(1 2,200-1 2,700 f e e t ) c o n t a i n s coa l , conglomerate, sandstone, mudstone, s i l t s t o n e ,

and was depos i t ed i n a f l u v i a1 env i ronment. The Eocene o r 01 de r s e c t i o n

(1 2,700-1 4,460 f e e t ) c o n t a i n s i n t e rbedded sandstone, s i 1 t s t o n e , rnudstone,

and abundant, t h i c k coa l beds. The i n t e r v a l f rom 14,460 t o 14,889 f e e t c o n t a i n s

q u a r t z i t e , marble, and p h y l l i t e o f probahl e Pa leozo ic age.

I n o r d e r t o have a permeahi l i t y o f 1 I ~ D , a sandstone i n t h e No. 2 we1 1

must have a t l e a s t 13 pe rcen t p o r o s i t y . On t h e b a s i s o f c o r e data, sandstones

w i tl7 13 pe rcen t o r more p o r o s i t y occur above 9000 f e e t i n t h e we1 1. P o r o s i t y

and p e r m e a b i l i t y r e d u c t i o n a r e a f u n c t i o n o f compact ion, a u t h i g e n i c m ine ra l

growth, and cementat ion.

A thermal g r a d i e n t of 2.0ZoF/100 f e e t was c a l c u l a t e d f o r t h e s e c t i o n

above 11,000 f e e t ; below t h i s depth t h e mean g r a d i e n t i s 2.5OoF/100 f e e t .

The o rgan i c m a t t e r i s p redominan t l y Type 111, humic, gas-prone kerogen.

S u f f i c i e n t m a t u r i t y f o r peak o i l gene ra t i on e x i s t s below 10,600 f e e t and c rude

o i l cou ld be preserved t o about 14,000 f e e t . M inor occurrences o f gas and

l i q u i d hydrocarbons were observed i n samples o b t a i n e d be low 10,000 f e e t ,

Methane, t hough t t o be o f b i o g e n i c o r i g i n , i s p resen t i n a few sands above 3000

f e e t ,

Four se ismic ho r i zons were mapped and c o r r e l a t e d : t h e basement uncon fo rmi ty

( A ) , mid-Eocene ( ? ) unconformi t y (B-1 ) , mid-01 igocene t r a n s g r e s s i v e mar ine

f a c i e s ( C ) , a n d l a t e O l i g o c e n e r e g r e s s i v e f a c i e s ( D ) .

I n t e r v a l v e l o c i t i e s c a l c u l a t e d f rom t h e son i c l o g a r e i n agreement w i t h

those f rom nearby s t a c k i n g v e l o c i t i e s t o a dep th o f 6100 feet . Below t h i s

dep th t h e compara t i ve l y h i g h e r i n t e r v a l v e l o c i t i e s p robab l y a r e a f u n c t i o n o f

d i f f e r e n t c o l l e c t i o n methods. L i t h o l o g i c d i f f e r e n c e s between t h e two subbasins

p robab l y account f o r a steeper t ime-dep th cu r ve i n t h e No. 2 w e l l t h a n in t h e

4 0 1 e l l . Depth convers ions o f se ismic da ta ( v e l o c i t y su rvey) c o u l d n o t be

pub l i shed o r u t i l i z e d i n t h i s s tudy because o f i t s l o n g e r p r o p r i e t a r y te rm

(USGS, Conserva t ion D i v i s i o n , Pol i c y Paper, January 2 2 , 1982).

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Sas in COST No. 2. Report t o ARC0 O i l and Gas Company.

APPENDIX 1

Well Data and Consu l tan ts Repor ts A v a i l a b l e f o r P u b l i c I n s p e c t i o n , Nor ton Sound COST No. 2 Well

Schl umberger O f f sho re Serv ices Anchorage, A1 aska

2 i n . Borehol e Compensated Sonic Log Runs 1, 2, 3 1180-14,836 f t

5 i n . Borehole Compensated Sonic Log Runs 1, 2, 3 1180-14,836 f t

5 i n . Cement Bond Log V a r i a b l e D e n s i t y Run 1

2 i n . Compensated Format ion D e n s i t y Log Gamma-Gamma Runs 1, 2, 3 1180-14,860 ft

5 i n . Compensated Format ion D e n s i t y Log Gamma-Gamma Runs 1, 2, 3 11 80-1 1,860 ft

2 i n . Compensated Neutron Format ion D e n s i t y Log Runs 1, 2 1180-11,872 ft

5 i n . C~mpensated Neutron Format ion D e n s i t y Log Runs 1 , 2 1180-1 1,872 ft

5 i n . Cyberd ip Run 1 1180-4634 f t

5 i n . Cyberd ip Run 2 4666-1 1,875 f t

2 i n . Cyberd ip r u n 2 4666-1 1,875 f t

5 i n . Oipmeter Run 1 1180-4634 f t

5 i n . D ipmeter Run 2 4666-1 1,875 f t

5 i n . D i pmeter Run 3 11,854-1 4,870 f t

D i r e c t i o n a l Log 8-30-82 Run 1 11,854-14,870 f t

a Schlurnberger - con t .

2 i n . Dual I n d u c t i o n - SFL Run 1, 2, 3 1130-14,870 f t

5 i n . Dual I n d u c t i o n - SFL R u n 1 , 2 , 3 1180-14 ,870 f t

2 i n . Dual I n d u c t i o n - SFL w/L inear C o r r e l a t i o n Log Runs 1, 2, 3 1180-14,870 f t

1 i n . Dual I n d u c t i o n - SP-GR L i n e a r Run 2 4666-1 1,871 f t

2 i n . LDT-CNL-NGT LDT P o r o s i t y Run 3 11,874-14,860 f t

5 i n . LDT-CNL-NGT LTD P o r o s i t y Run 3 11,874-1 4,860 f t

2 i n . LOT-CNL-NGT CNL P o r o s i t y Run 3 11,854-1 4,860 f t

5 i n . LDT-CNL-NGT CNL P o r o s i t y Run 3 11,854-1 4,860 f t

2 i n . LDT Bu lk Oen i s t y CNL P o r o s i t y Run 3 11,854-14,840 f t

5 i n, LDT Bul k D e n s i t y CNL P o r o s i t y Run 3 11,854-1 4,840 f t

'2 i n . Long Spaced Sonic Runs 1, 2, 3 1180-14,860 f t

5 i n . Long Spaced Sonic Runs 1, 2, 3 1180 -14 ,860 f t

5 i n . Long Spaced Sonic Waveforms Run 1 1180-4534 f t

5 i n . Long Spaced Sonic Waveform Run 2 4666-1 1,864 f t

5 i n , Long Spaced Sonic Waveform Run 3 11,854-1 4,860 f t

2 i n . M i c ro -P rox im i t y Log Run 2 4666-1 1,875 f t

a Schl umberger - con t . 5 i n , Fl icro-Proxirni t y Log

Run 2 4660-1 1,875 f t

2 i n . NGT Run 1 1180-4602 f t

2 i n . NGT Run 2 4666-1 1,840 f t

2 i n . NGT Run 3 11,854-1 4,830 f t

5 i n . NGT Run 1 1180-4602 f t

5 i n . NGT Run 2 4666-1 1,840 f t

5 i n . NGT Run 3 11,854-14,860 f t

Repeat Format ion Tes te r Run 1 6-21-82

Repeat Format ion Tes te r Run 2 7-28-82

Repeat Format ion T e s t e r Run 3 8-31-82

Temperature Log Run 1 380-14,870 f t

Geodip P a t t e r n Recogn i t i on 6 Fo lders P r i n t o u t 6 Fo lde rs Charts Sepia 1 3500-5800 f t 2 5800-71 00 f t 3 71 00-8450 f t 4 10,400-11,500 f t 5 11,900-13,800 f t 6 13,800-14,600 f t

D i r e c t i o n a l Survey Run No. 2 P l o t and P r i n t Out 4666-1 1,868 f t

D i r e c t i onal Survey Run No. 3 P l o t and P r i n t Out 11,854-14,870 f t

Loyg i ng Qua1 i t y Con t ro l Survey Runs 1 , 2, and 3

0 Schl umberger - cont .

H igh R e s o l u t i o n D i pmeter C l u s t e r L i s t i n g s Run 1 , 1202-4628 f t Run 2, 4702-1 1,868 f t Run 3, 11,857-12,160 f t

E x p l o r a t i o n Logging I nc , (Ex1 og) Anchorage, Alaska

Downhol e Logging Whil e D r i l l i ng Log 450-1 1,220 f t , Sepia

F i na l Geochemical We1 1 Repor t Vol . 1

Organic Carbon and P y r o l y s i s Data 1230-14,491 f t , 33 p.

Organic Carbon and P y r o l y s i s Data Cores 4, 5, 6, 7, and 9, 4 p.

Head Space Gas Ana l ys i s 1230-4590, 4 p .

Temperature Data Log Raw D a t a Sepia 154-14,889 ft

Temperature Data Log End To End Sepia 154-1 4,889 f t

Pressure E v a l u a t i o n Log Sepia 154-14,889 f t

D r i l l i ng Data Pressure Log Sepia 154-14,889 f t

Mud R e s i s t i v i t y Log Sepia 154-14,889 f t

W i re1 i ne D a t a Pressure Log Sepia 154-14,889 f t

Format ion Eval u a t i o n Log Sepia 154-14,889 f t

Geochemical Eval u a t i o n Log Sepia 1236-14,889 f t

End o f We1 1 Repor t 1 Vol.

0 B i rdwel 1 D i v i s i on Sei s~nograph Se rv i ce Co rpo ra t i on Tu lsa . Oklahoma

A i rgun Seismic V e l o c i t y Survey 6-21 -82 1 180-4634 A-U 7-26-82 4666-1 1 ,875 A-Z 7-26-82 4666-11,875 AA-AD 7-28-82 4673-1 1 ,875 A-Z 7-28-82 4637-1 1,875 AA-DD

V e r t i c a l Seismic P r o f i l e

F i n a l Sei srni c Vel o c i ty Survey and Log Cal i b r a t i o n

ARC0 Alaska Inc. Anchoraae. A laska

D r i l l Stem T e s t No. 1 Procedures

D r i l l Stem T e s t No. 2 Procedures

W e l l s i t e Core D e s c r i p t i o n s Cores 1-13, 13 r e p o r t s

S idewa l l Core D e s c r i p t i o n s 1324-15,856 f t , 12 p.

L i tho1 ogy Log Sepia RKB-14,900 f t

ADP Sundry No t i ces We1 1 Cornpl e t i o n Report

Core L a b o r a t o r i e s , Inc . D a l l as, Texas

C o r r e l a t i o n Core Graphs Sepia 4600-7100, 7950-10,300, 11,150-13,000, 13,340-14,900 f t

Core Photos 1-23 U l t r a v i 01 e t 1 i ght 1-23 White 1 i ght

Core Gamma P r e l i m i na ry Data Cores 1-6, 6 p.

F i n a l Permeabi 1 i t y and P o r o s i t y Report on Cores, 3 p.

0 Core L a b o r a t o r i e s , Inc. - con t ,

F i n a l Permeabi 1 i t y and P o r o s i t y Report on S idewa l l Cores, 4 p.

B i o s t r a t i graph i c s , Inc . San Diego, Cal i f o r n i a

F i n a l B i o s t r a t i graph i c Repor t

B i o s t r a t i g raph i c Char ts Sepia Foramin i fe ra : 1230-1 3,850 f t Spores, Pol l e n , M i c rop l ankton: 1230-1 3,850 f t Diatoms: 1230-7070 f t

Pal eobotany Repor t 5 P*

G l obal Geochemi s t r y Co rpo ra t i on Canoga Park, Cal i f o r n i a

Ca t ion , Anion, and I s o t o p e Data 7370, 10,300, 14,850 f t

Geochemical Ana l ys i s o f D.S.T. Samples 1 and 2 10-8-82

Tel edyne I sotopes Westwood, New Jersey

K-AR Age Determi n a t i o n Sample KA 82-595, 596, 597

AGAT Consu l tan ts Inc . Denver, Colorado

AGAT Repor t , 5 vo l .

Robertson Research Houston, Texas

Geochemical Anal y s i s F i na l Repor t 1 vo l .

.\ hemlcal and Geol ogical Labo ra to r i es o f Alask;

Water Analysis Reports KFT Samples, 2 p.

N a t e r Analys is Reports 1 4 P.

, i? ra l s Yanagement Service :borage, A laska

Env i tonmental Assessment

I n c . den, Colorado

Core Ve loc i t y Data

Chemical and Geo log ica l Labo ra to r i es o f A laska , Inc. * Anchorage, Alaska

Water A n a l y s i s Reports RFT Samples, 2 p .

Water* A n a l y s i s F e p o r t s $ 4 p.

M ine ra l s Management S e r v i c e Anchorage, A1 as ka

Env i ronmental Assessment

P B I , Inc. Go1 den, Col orado

Core V e l o c i t y D a t a

cal Sound A1 aska F. D.

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