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Bureau of Mines Report of lnvestigations/l987 Accurate Directional Borehole Drilling: A Case Study at Navajo Dam, New Mexico By S. J. Kravits, A. Sainato, and G. L. Finfinger UNITED STATES DEPARTMENT OF THE INTERIOR
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Bureau of Mines Report of lnvestigations/l987
Accurate Directional Borehole Drilling: A Case Study at Navajo Dam, New Mexico
By S. J. Kravits, A. Sainato, and G. L. Finfinger
UNITED STATES DEPARTMENT O F T H E INTERIOR
Report of Investigations 9102
Accurate Directional Borehole Drilling: A Case Study at Navajo Dam, New Mexico
By S. J. Kravits, A. Sainato, and G. L. Finfinger
UNITED STATES DEPARTMENT OF THE INTERIOR Donald Paul Hodel, Secretary
BUREAU OF MINES David S. Brown, Acting Director
Library of Congress Cataloging in Publication Data :
Kravits, S. J. (Stephen J.) Accurate directional borehole drilling.
(Report of investigations ; 9102)
Bibliography: p. 18.
Supt. of Docs. no.: 1 28.23: 9102.
1. Directional drilling-New Mexico-Navajo Dam. I. Sainato, Albert. 11. Finfinger, Gerald L. 111 Title. IV. Series: Report of investigations (United States. Bureau of Mines) ; 9102.
CONTENTS Page
A b s t r a c t ........................................................................ 1 I n t r o d u c t i o n ................................................................... 2 Acknowledgments ................................................................ 2 T e s t s i t e ...................................................................... 2 D r i l l i n g equipment ............................................................. 3
H y d r a u l i c d r i l l .............................................................. 3 In -ho le motor ................................................................ 3 Boreho le t r a j e c t o r y c o n t r o l d e v i c e s .......................................... 5
Survey ing equipment and p r o c e d u r e s ............................................. 9 S i n g l e - s h o t s u r v e y i n s t r u m e n t ................................................ 9 Survey ing accuracy ........................................................... 10
P l a n n i n g t h e boreho le .......................................................... 11 D i r e c t i o n a l d r i l l i n g t h e d e m o n s t r a t i o n b o r e h o l e ................................ 13
E f f e c t i v e n e s s i n c o n t r o l l i n g b o r e h o l e t r a j e c t o r y ............................. 13 Boreho le punchout and i n v e s t i g a t i n g e r r o r i n az imuth ......................... 15
Conc lus ions .................................................................... 18 R e f e r e n c e s ..................................................................... 18 Appendix.--Dril l and b o r e h o l e s u r v e y log^.........................^............ 19
ILLUSTRATIONS
Navajo Dam l o c a t i o n map .................................................. 3 Navajo Dam r i g h t abutment ................................................ 4 Navajo Dam d e m o n s t r a t i o n b o r e h o l e d r i l l s i t e ............................. 4 H y d r a u l i c d r i l l and c o n t r o l p a n e l ........................................ 5 In-hole motor s c h e m a t i c .................................................. 5 In-hole motor o p e r a t i n g p a r a m e t e r s ....................................... 6 P o l y c r y s t a l l i n e diamond c u t t e r b i t s ...................................... 6 In-hole motor equipped w i t h a 2O ben t hous ing ............................ 6 S i d e f o r c e d iagram ....................................................... 7 Var ious t o o l f a c e s e t t i n g s and t h e i r e f f e c t s on boreho le t r a j e c t o r y ...... 8 S i n g l e - s h o t d i r e c t i o n a l s u r v e y i n s t r u m e n t ................................ 9 Reading developed s u r v e y f i l m d i s k ....................................... 9 Survey hardware .......................................................... 10 Nonmagnetic d r i l l c o l l a r and compass s p a c i n g s e l e c t i o n c h a r t ............. 11 V e r t i c a l s e c t i o n of p lanned d e m o n s t r a t i o n boreho le ....................... 12 ............................... Map view of p lanned d e m o n s t r a t i o n b o r e h o l e 12 V e r t i c a l s e c t i o n of d e m o n s t r a t i o n b o r e h o l e ....................a.e........ 13 P l a n view of d e m o n s t r a t i o n b o r e h o l e ..................................... 14 Var ious ben t hous ings .................................................... 14 Borehole punchout ........................................................ 17
TABLES
1. Measured d e f l e c t i o n r a t e s u s i n g 2' bent hous ing .......................... 1 6 A-1 . Log of d i r e c t i o n a l d r i l l i n g p a r a m e t e r s ................................... 19 A-2 . Demonst ra t ion b o r e h o l e s u r v e y l o g and l o g of d e s i r e d d e p a r t u r e s .......... 22
UNIT OF MEASURE ABBREVIATIONS USED
EMU e l e c t r o m a g n e t i c u n i t Ib f
f t f o o t m i n
f t 0 l b f f o o t pound ( f o r c e ) nT
g a l / m i n g a l l o n p e r minute p s i
hp horsepower ~ s i g
i n i n c h r /min
i n / m i n i n c h p e r minute V a c
IN THIS REPORT
pound f o r c e
minute
n a n o t e s l a
pound p e r s q u a r e i n c h
pound p e r s q u a r e i n c h , gauge
r e v o l u t i o n p e r minute
v o l t , a l t e r n a t i n g c u r r e n t
ACCURATE DIRECTIONAL BOREHOLE DRILLING: A CASE STUDY AT NAVAJO DAM, NEW MEXICO
1 By S. J. Kravits,' A. S a i n a t ~ , ~ and G. L. Finfinger3
ABSTRACT
T h i s r e p o r t d e s c r i b e s a p r o j e c t conducted by t h e Bureau of Mines i n which t h e a c c u r a t e d i r e c t i o n a l d r i l l i n g of a boreho le was demons t ra t ed w i t h t h e o b j e c t i v e of i n t e r c e p t i n g a d e s i g n a t e d t a r g e t . The p r o j e c t was conducted a t Navajo Dam i n n o r t h e r n New Mexico a t t h e r e q u e s t of t h e Bu- r e a u of Reclamation. Borehole s u r v e y and d r i l l l o g s a r e p rov ided i n a n appendix .
The t r a j e c t o r y of t h e d e m o n s t r a t i o n b o r e h o l e was des igned t o i n t e r c e p t a 5 - f t - r a d i u s t a r g e t a t t h e f i n a l o r "punchout" d i s t a n c e of 885 f t . The e l e v a t i o n of t h e b o r e h o l e a t t h i s d i s t a n c e was w i t h i n t h e t a r g e t ; t h e b o r e h o l e punchout c o o r d i n a t e s were 8.81 f t sou thwes t of t h e t a r g e t . A s a r e s u l t of t h e demons t ra t ed a c c u r a c y , t h e Bureau of Reclamat ion h a s c o n t r a c t e d t h e a c c u r a t e d r i l l i n g of b o r e h o l e s a s l o n g a s 600 f t from t h e i n s i d e of a s h o r t t u n n e l , t o c o n t r o l w a t e r seepage i n t h e r i g h t a b u t - ment. T h i s r e s u l t e d i n a s u b s t a n t i a l c o s t s a v i n g s compared t o t h e o r i g - i n a l p l a n of c o n s t r u c t i n g a l o n g e r t u n n e l and d r i l l i n g 150-ft bo reho les .
' ~ i n i n g e n g i n e e r . 2 ~ i n i n g e n g i n e e r i n g t e c h n i c i a n . 3 ~ u p e r v i s o r y g e o l o g i s t .
P i t t s b u r g h Research C e n t e r , Bureau of Mines, P i t t s b u r g h , PA.
INTRODUCTION
The Bureau of Reclamation, U.S. Depart- ment of t h e I n t e r i o r , r eques ted t h e Bu- r e au of Mines, through In te ragency Agree- ment No. 1409-0070-1212, t o demonstra te t h e accuracy of d i r e c t i o n a l d r i l l i n g a nea r -ho r i zon t a l borehole t o i n t e r c e p t a de s igna t ed t a r g e t . The Bureau of Recla- mat ion ' s o b j e c t i v e was t o determine t h e f e a s i b i l i t y of u s ing a c c u r a t e l y d r i l l e d boreholes t o c o n t r o l wa te r seep- age through open j o i n t s i n bedrock foun- d a t i o n s of embankment dams.
The Bureau of Mines has researched and demonstra ted a c c u r a t e d i r e c t i o n a l d r i l l - i n g a s p a r t of i t s methane c o n t r o l pro- gram (1-3).4 - - I n 1979, a d i r e c t i o n a l s u r f a c e borehole was d r i l l e d us ing an in-hole motor5 t o a measured depth of
1,595 f t , main ta in ing an a r c of 6" per 100 f t and coming w i t h i n 3 f t of i n t e r - c ep t i ng t h e P i t t sbu rgh Coalbed 1,012 f t below t h e su r f ace . Five h o r i z o n t a l meth- ane d ra inage boreholes were t hen d r i l l e d from t h e s u r f a c e borehole , t o t a l i n g 9,544 f t .
The Bureau has a l s o demonstrated d r i l l - i n g accuracy i n d r i l l i n g long h o r i z o n t a l methane dra inage boreholes i n underground c o a l mines. Methane dra inage boreholes have been d r i l l e d t o dep ths g r e a t e r t han 2,000 f t , main ta in ing v e r t i c a l borehole t r a j e c t o r y w i th in t h e coalbed (approxi- mately 6 f t ) whi le c o n t r o l l i n g h o r i z o n t a l t r a j e c t o r y a s d e s i r e d t o prevent i n t e r - c ep t i on by f u t u r e mining (2-2). -
ACKNOWLEDGMENTS
The coopera t ion of t h e Bureau of Recla- Navajo Dam maintenance s t a f f f o r t h e i r mation was c r i t i c a l i n t h e s u c c e s s f u l cont inued suppor t and a s s i s t a n c e du r ing complet ion of t h i s p r o j e c t . The au tho r s t h i s p r o j e c t . The a u t h o r s a l s o thank wish t o thank Hunter C. H a r r e l , geolo- Ed J. Blythe, Jr., we l l p lann ing eng i - g i s t , Engineer ing and Research Cente r , nee r , NL Sperry-Sun, Rosenburg, TX f o r Denver, CO; William C. Eh l e r , g e o l o g i s t , t e c h n i c a l a s s i s t a n c e provided i n improv- Durango (CO) P r o j e c t s O f f i c e ; Leonard i n g survey ing accuracy. T r u j i l l o , Navajo Dam supe r in t enden t ; and
TEST SITE
Navajo Dam i s a zoned embankment s t r u c - t u r e i n no r the rn New Mexico, 39 mi les e a s t of Farmington, NM, and about 35 mi l e s s o u t h e a s t of Durango, CO ( f i g . 1 ) . It is one of t h e key s t r u c t u r e s of t h e Colorado River S torage P r o j e c t , regu- l a t i n g t h e f lows of t h e San Juan River and prov id ing s t o r a g e f o r Navajo Ind i an I r r i g a t i o n P r o j e c t . It a l s o p rov ides a f a c i l i t y f o r r e c r e a t i o n and f i s h and w i l d l i f e conserva t ion . Navajo Dam,
' unde r l ined numbers i n p a r e n t h e s e s r e - f e r t o i t e m s i n t h e l i s t o f r e f e r e n c e s p r e c e d i n g t h e appendix .
cons t ruc t ed from 1958 t o 1963, is approx- imate ly 400 f t i n s t r u c t u r a l h e i g h t , 3,600 f t i n c r e s t l e n g t h , 30 f t i n t o p width, and 2,500 f t i n maximum base width (6). The r i g h t abutment of t h e dam was chosen f o r t h e l o a c t i o n of t h e demonstra- t i o n borehole , wi th designed punchout occu r r i ng nea r t h e top of t h e s p i l l w a y ( f i g s . 2-3).
5 ~ h e te rm i n - h o l e i s synonymous w i t h downhole. The a u t h o r s f e e l i n - h o l e i s more d e s c r i p t i v e l y a c c u r a t e when b o r e h o l e t r a j e c t o r y i s n e a r h o r i z o n t a l .
DRILLING EQUIPMENT
A Diamant ~ o a r t ~ DBH 700 h y d r a u l i c c o r e d r i l l and a 2-7/8-in-OD high- torque, non- magnetic in-hole motor manufactured by S l i m d r i l , Inc . , were used t o d r i l l t h e borehole . The in -ho le motor was equipped w i t h a bent hous ing and two 3-1/2-in-OD p o l y c r y s t a l l i n e diamond c u t t e r b i t s (used s e p a r a t e l y ) , one manufactured by Longyear and one by S l i m d r i l , Inc.
' ~ e f e r e n c e t o s p e c i f i c equ ipmen t d o e s n o t imp ly endor semen t by t h e Bureau o f Mines.
Key mop
COLORADO
MEXICO u
I 1 LEGEND
@ U. S. highway @ State highway - Unpaved road
---- State boundary
County boundary
o Townorcity
0 10 20
Scale, miles
FIGURE 1.-Navajo Dam location map. Adapted from Bureau of Reclamation map.
HYDRAULIC D R I L L
The main components of t h e Diamant Boar t DBH 700 u n i t a r e t h e d r i l l i t s e l f , c o n t r o l p a n e l , and power u n i t ( f i g . 4 ) . To d r i l l t h e demons t ra t ion boreho le , t h e d r i l l was p o s i t i o n e d h o r i z o n t a l l y . The power u n i t i s equipped w i t h two h y d r a u l i c r a d i a l p i s t o n pumps, one f o r t h r u s t and one f o r r o t a t i o n , bo th powered by a s i n - g l e 40-hp, 440-V a c e l e c t r i c motor.
IN-HOLE MOTOR
The 2-7/8-in-OD high- torque in-hole mo- t o r i s a pos i t ive -d i sp lacement h y d r a u l i c motor t h a t r o t a t e s t h e d r i l l b i t w i t h o u t r o t a t i n g t h e d r i l l s t r i n g . The in-hole motor c o n v e r t s t h e h y d r a u l i c horsepower g e n e r a t e d by t h e f low of t h e d r i l l i n g f l u i d ( w a t e r ) under p r e s s u r e i n t o t o r q u e and i n t o t h e r o t a t i o n a l speed o r mechani- c a l power t h a t d r i v e s t h e d r i l l b i t (5) . The components of t h e high- torque motor a r e i d e n t i f i e d i n f i g u r e 5.
When d r i l l i n g f l u i d is pumped through t h e d r i l l s t r i n g and t h e in -ho le motor a t r a t e s of 30 t o 70 gal /min a t d i f f e r e n t i a l p r e s s u r e s of 250 t o 625 p s i g , t h e h e l i c a l s t a i n l e s s s t e e l r o t o r r o t a t e s i n s i d e t h e rubber molded s t a t o r . The range of Slim- d r i l o p e r a t i n g paramete rs i s shown i n f i g u r e 6; t h e a c t u a l pa ramete rs a p p l i e d a r e l i s t e d i n t a b l e A-1 (appendix) . Ro- t a t i o n of t h e d r i v e s h a f t , p o s i t i o n e d w i t h i n t h e b e a r i n g package, i s t r a n s - m i t t e d by t h e f l ex-coupl ing , c o n v e r t i n g t h e e c c e n t r i c r o t a r y motion of t h e h e l i - c a l r o t o r t o c o n c e n t r i c motion. The d r i v e s u b i s connected t o t h e d r i v e s h a f t and i s t h e on ly r o t a t i n g e x t e r n a l compo- n e n t of t h e in -ho le motor. The d r i l l b i t i s f a s t e n e d t o t h e d r i v e sub. Two 3-1/2- in-OD p o l y c r y s t a l l i n e diamond c u t t e r b i t s , one each from Longyear and Slim- d r i l , Inc . , were e q u a l l y used t o d r i l l
FIGURE 2.-Navajo Dam right abutment.
FIGURE 3.-Navajo Dam demonstration borehole drill site.
FIGURE 4.-A, Hydraulic drill; 8, control panel. Power unit not shown.
Bearing package NW rod box threa
NQ rod Crossover sub
box thread
Not to scale
FIGURE 5.-In-hole motor schematic. Stator, rotor and exterior nousing are nonmagnetic. Bearing package and drive sub are magnetic.
t h e demons t ra t ion boreho le ( f i g . 7). BOREHOLE TRAJECTORY CONTROL DEVICES P o l y c r y s t a l l i n e diamond c u t t e r b i t s a r e recommended f o r u s e w i t h in-hole motors Various t y p e s of d e v i c e s can be used because t h e y a r e des igned t o o p e r a t e a t w i t h in-hole motors t o c o n t r o l boreho le h i g h r o t a t i n g speeds f o r extended p e r i - t r a j e c t o r y . These i n c l u d e b e n t hous ings , ods. The demons t ra t ion b o r e h o l e ' s h o r i - bent s u b s , e c c e n t r i c s u b s , and d e f l e c t i o n z o n t a l and v e r t i c a l boreho le t r a j e c t o r i e s shoes. An in-hole motor equipped w i t h a were c o n t r o l l e d d u r i n g in-hole motor 2' ben t housing i s shown i n f i g u r e 8. d r i l l i n g by u s i n g c o n t r o l dev ices .
MOTOR PRESSURE DIFFERENTIAL, psi
FIGURE 6.-In-hole motor operating parameters. Water sup- plied to in-hole motor under pressure by two triple-piston pumps.
- Scale, in
FIGURE 7.-Polycrystalline diamond cutter bits.
While d r i l l i n g , t h e r e i s continuous FIGURE 8.-In-hole motor equipped with a 2' bent housing. con tac t between t h e convex s i d e of t h e bent housing and t h e wa l l of t he bore- i s c a l l e d t o o l face d i r e c t i o n and is ho le ; t h i s i s commonly c a l l e d s i d e force. t h e d i r e c t i o n borehole t r a j e c t o r y w i l l The r e s u l t a n t r e a c t i o n of t h e s i d e f o r c e follow. Various t o o l f a c e s e t t i n g s and exe r t ed on t h e wa l l of t h e borehole i s a t h e i r e f f e c t s on borehole v e r t i c a l and f o r c e exer ted on t h e b i t i n t h e oppos i te ho r i zon ta l t r a j e c t o r i e s a r e shown i n d i r e c t i o n o r 180' away ( f ig . 9). The d i - f i g u r e 10. r e c t i o n of t h e fo rce exer ted on t h e b i t
Side force (at 0")
Tool face at 180" (low s~de) force exerted on bit
(reaction of s ~ d e force w tool face at 1 80° 1
Side force (at 0" )
Tool face at 180° (low s ~ d e )
Dlrect~on of force exerted on b ~ t resulting in vertlcal
drop of hole trajectory FIGURE 9.-Side force diagram. Above in-hole motor equipped with bent housing; below, side force
schematic.
Def l ec t ion r a t e s p e r t a i n i n g t o known t o o l f a c e s e t t i n g s a r e r a t e s a t which borehole i n c l i n a t i o n and azimuth (bear- i n g ) change o r d e f l e c t dur ing d r i l l i n g . The r a t e of change i n borehole i n c l i n a - t i o n i s t h e v e r t i c a l d e f l e c t i o n r a t e ; t h e h o r i z o n t a l d e f l e c t i o n r a t e i s t h e r a t e of change i n azimuth. Es tab l i shed
d e f l e c t i o n r a t e s would be used t o pe r i - o d i c a l l y p r o j e c t o r estimate b i t p o s i t i o n 16 f t ahead of t h e cu r r en t survey depth and t o decide what t o o l f ace s e t t i n g should be appl ied t o t h e next d r i l l i n g i n t e r v a l i n order t o maintain des i r ed borehole t r a j e c t o r y . V e r t i c a l and hor i - z o n t a l d e f l e c t i o n r a t e s a r e determined by
Maximum build in inclination
5. Left H 5' Right
Maximum and hold
5O Right
5" Maximum azimuth turn
and hold inclination
Maximum drop in inclination
FIGURE 10.-Various tool face settings and their effects on borehole trajectory. Black arrow depicts tool face setting of 45' right, which would result in borehole trajectory building inclination and azimuth turning right (east).
observing t h e change i n i n c l i n a t i o n and azimuth from t h e previous t o t h e cu r r en t borehole survey depth. For example, re- f e r r i n g t o t h e t h i r d page of t a b l e A-2, t h e v e r t i c a l and h o r i z o n t a l d e f l e c t i o n r a t e s observed from survey depths 449 t o 459 f t were 0.09"/ft (0.9" dur ing 10-ft i n t e r v a l ) and 0.19"/ft ( e a s t is posi- t i v e ) , r e spec t ive ly . A t o o l f a c e s e t t i n g of 60" t o 80" r i g h t was appl ied us ing a 2" bent housing while d r i l l i n g from 445 t o 475 f t . When t h e survey was conducted a t 459 f t , t he b i t depth was 475 f t . To p r o j e c t t h e i n c l i n a t i o n a t t he b i t depth of 475 i t , t h e e s t a b l i s h e d v e r t i c a l de- f l e c t i o n r a t e of 0 .09"/f t was mul t ip l i ed by 16 f t and added t o t h e surveyed i n c l i - n a t i o n a t 459 f t . This r e s u l t e d i n a p ro j ec t ed i n c l i n a t i o n of 101.8". The azimuth a t t h e b i t depth was pro jec ted t o be 343.0" by mul t ip ly ing t h e h o r i z o n t a l d e f l e c t i o n r a t e of 0.19"/ft by 16 f t and
adding t h e azimuth surveyed a t 459 f t of 340.0". The pro jec ted i n c l i n a t i o n and azimuth a t 475 f t were c l o s e t o t h e ac- t u a l r e s u l t s surveyed l a t e r a t 479 f t ( t a b l e A-2). Angle averaging, which i s a surveying c a l c u l a t i o n method, was used t o c a l c u l a t e pro jec ted coord ina tes and e l e - va t ion a t t h e b i t (2, 6). Establ i shed d e f l e c t i o n r a t e s pe r t a in ing t o t o o l f a c e s e t t i n g s and bent housing used a r e pro- vided l a t e r i n t h e t e x t .
Tool f ace d i r e c t i o n s a r e changed by t u r n i n g t h e d r i l l s t r i n g clockwise wi th pipe wrenches t o a p o s i t i o n O0 t o 180" l e f t o r r i g h t from t h e c e n t e r l i n e a long t h e top of t h e boring. Borehole i n c l i n a - t i o n , azimuth, and t o o l f a c e d i r e c t i o n were cont inuously monitored and ad jus t ed t o achieve d i r e c t i o n a l c o n t r o l o r t o maintain t h e des i r ed h o r i z o n t a l and ver- t i c a l borehole t r a j e c t o r i e s .
SURVEYING EQUIPMENT AND PROCEDURES
SINGLE-SHOT SURVEY INSTRUMENT
An NL Sperry-Sun type B 120° magnetic d i r e c t i o n a l s ing le -shot survey instrument was used dur ing d r i l l i n g t o monitor bore- ho l e i n c l i n a t i o n , bear ing, and t o o l f a c e d i r e c t i o n ( f i g . 11). The e s s e n t i a l e l e - ments of t h e survey instrument a r e t h e compass, i n c l i n a t i o n u n i t , b a t t e r i e s and f i l m loading mechanism, l e n s and lamp holder , and mechanical t i m e r t h a t c o n t r o l s t h e e l e c t r i c a l c i r c u i t s and il- lumina tes t h e compass-inclination u n i t a t a p r e s e t time t o record t h e p e r t i n e n t d a t a on a f i l m d i s k (7). -
To conduct a survey, t he mechanical t imer of t h e survey instrument is set and t h e instrument is loaded with a f i l m disk. The loaded survey instrument is placed i n i t s p r o t e c t i v e cas ing and i n s e r t e d i n t h e hollow d r i l l rod. It i s pumped wi th water t o t h e back end of t h e in-hole motor, where i t a l i g n s wi th t h e o r i e n t i n g sub. The f i l m d i s k i s exposed a t a p r e s e t t ime, a f t e r which t h e i n s t r u - ment is r e t r i e v e d by a w i r e l i n e a t t ached t o t h e p r o t e c t i v e casing. The r e t r i e v e d instrument is removed from i t s p r o t e c t i v e cas ing , and t h e f i l m d i s k is removed, developed, and read ( f i g . 12).
FIGURE 11.-Single-shot directional survey instrument.
FIGURE 12.-Reading developed survey film disk.
SURVEYING ACCURACY
D i r e c t i o n a l d r i l l i n g accuracy i s p r i - mar i ly dependent on borehole surveying accuracy. Fac to r s t h a t i n f luence bore- h o l e accuracy inc lude inhe ren t accuracy of t h e survey ins t rument , magnetic d r i l l s t r i n g i n t e r f e r e n c e , survey frequency o r i n t e r v a l , and t h e c a l c u l a t i o n technique used t o compute borehole coord ina tes and e l e v a t i o n .
The NL Sperry-Sun type B 120" d i r ec - t i o n a l s ing le -shot survey instrument was used t o monitor borehole i n c l i n a t i o n , bea r ing , and t o o l f a c e o r i e n t a t i o n . The manufacturer ' s s p e c i f i e d t o l e r a n c e i n measuring bear ing f o r a r e c e n t l y c a l i - b r a t e d compass (survey instrument) i s '0.5O. Furthermore, t h e r e s o l u t i o n i n r ead ing t h e photographed compass bear ing on t h e f i l m d i s k i s a random 20.5". Con- s equen t ly , a p o t e n t i a l e r r o r of '1" ex- i s t s i n measuring borehole bear ings u s ing t h e s u b j e c t survey instrument . The accu- r acy i n surveying f o r i n c l i n a t i o n us ing t h e s u b j e c t survey instrument i s '0.12O. Wolff and deWardt (8) s t a t e t h a t , f o r a compass u n i t i n good cond i t i on , a gener- a l l y accepted sys t ema t i c accuray i s '1". Compass u n i t s measure magnetic n o r t h and r e q u i r e a d e c l i n a t i o n c o r r e c t i o n t o ob- t a i n t r u e north. Wolff and deWardt sug- g e s t t h a t d e c l i n a t i o n c o r r e c t i o n s ob- t a i n e d from c h a r t s may be i n c o r r e c t t o '0.5. The Nat ional Geophysical Data Cen- ter , Boulder, CO, o r t h e U.S. Geological Survey, Reston, VA, can supply an accu- r a t e d e c l i n a t i o n c o r r e c t i o n i f provided w i t h d r i l l s i t e ( c o l l a r ) coord ina tes and e l eva t ion . The d e c l i n a t i o n c o r r e c t i o n a t Navajo Dam d r i l l s i t e was 12" E '13 min. Random misalignment of t h e survey hard- ware and instrument w i th in t h e d r i l l
s t r i n g w i th r e spec t t o t h e borehole i s another p o s s i b l e source of e r r o r i n bore- h o l e surveying f o r bear ing and i n c l i n a - t i o n ( f i g . 13). The magnitude of t h i s source of e r r o r i s d i f f i c u l t t o de t e r - mine; Wolff and deWardt (8) e s t ima te i t a t approximately '0.2 t o *O.SO.
Compass-type surveying instruments sense only t he d i r e c t i o n of t h e l o c a l magnetic f i e l d vec to r and t h e r e f o r e are sub jec t t o sys temat ic d r i l l s t r i n g i n t e r - ference. To reduce d r i l l s t r i n g i n t e r - fe rence , compass-type survey instruments must be proper ly spaced i n s i d e adequate l eng ths of nonmagnetic d r i l l c o , l l a r (NMDC). The NMDC used t o d r i l l t h e jdem- o n s t r a t i o n borehole cons is ted of a non- magnetic in-hole motor (nonmagnetic ro- t o r and housing 12 f t i n length , bear ing package and b i t made of magnetic m a t e r i a l 2 f t i n l eng th ) and 100 f t of NQ-size w i r e l i n e nonmagnetic s t a i n l e s s steel d r i l l rod. Previous Bureau experience i n d i r e c t i o n a l d r i l l i n g long h o r i z o n t a l boreholes i n c o a l f o r methane dra inage has shown t h a t compass spacing of 20 f t above t h e bottom end of 100 f t of NMDC s u f f i c i e n t l y reduces d r i l l s t r i n g i n t e r - ference. NL Sperry-Sun has completed se- l e c t i o n c h a r t s a s guides f o r e s t ima t ing compass spacing based on geographical l o c a t i o n (ho r i zon ta l component of t h e e a r t h ' s magnetic f i e l d i n t e n s i t y v a r i e s wi th l o c a t i o n ) , borehole i n c l i n a t i o n , and bear ing, a s i nd i ca t ed i n f i g u r e 14 ( 9 ) . Based on t h e s e l e c t i o n c h a r t shown f o r t h e Navajo Dam loca t ion , uncorrected bear ing of N 10" W , and i n c l i n a t i o n of 90°, t h e compass should be loca ted 20 f t from t h e bottom of t h e NMDC. While con- duc t ing a borehole survey , t h e NL Sperry- Sun s ing le -shot was placed 13 f t from t h e bottom of t h e NMDC, o r 16 f t from t h e
FIGURE 13.-Survey hardware. A , snubber; 19, centralizing pumpdown washers; C, muleshoe.
BEARING FROM MAGNETIC NORTH OR SOUTH, deg
(Uncorrected for decl inat ion)
F ing
'IGURE 14.-Nonmagnetic drill collar and compass spac- selection chart.
b i t . Although t h i s s p a c i n g was 7 f t less t h a n t h e e s t i m a t e d compass s p a c i n g s , hav- i n g t h e compass c l o s e r t o t h e b i t en- hanced t h e accuray i n p r o j e c t i n g t h e cur- r e n t p o s i t i o n of t h e b i t from t h e su rvey p o s i t i o n .
Two r e l a t e d f a c t o r s t h a t a f f e c t bore- h o l e su rvey ing accuracy a r e su rvey ing f requency and t h e su rvey ing c a l c u l a t i o n t e c h n i q u e used t o determine boreho le co- o r d i n a t e s and e l e v a t i o n . It is g e n e r a l l y accep ted t h a t r e g a r d l e s s of c a l c u l a t i o n t e c h n i q u e a p p l i e d , s h o r t su rvey i n t e r v a l s w i l l r e s u l t i n i n c r e a s e d accuracy (10). Borehole su rveys were conducted a t 10-ft d r i l l i n g i n t e r v a l s a t Navajo Dam. Of t h e dozen o r s o su rvey ing c a l c u l a t i o n t ech- n i q u e s a v a i l a b l e , balanced t a n g e n t i a l , r a d i u s of c u r v a t u r e , minimum c u r v a t u r e , and a n g l e averag ing a r e g e n e r a l l y ac- c e p t e d a s p rov id ing s i m i l a r and a c c e p t - a b l e r e s u l t s (10) . A r a d i u s of c u r v a t u r e program a d a p t e r f o r a Hewlett Packard 15C c a l c u l a t o r was used t o c a l c u l a t e boreho le c o o r d i n a t e s and e l e v a t i o n . Angle averag- i n g was used p e r i o d i c a l l y t o check t h e r a d i u s of c u r v a t u r e r e s u l t s .
PLANNING THE BOREHOLE
The boreho le s t a r t i n g c o o r d i n a t e s were N 19,567.69, E 52,697.69; e l e v a t i o n a t t h e c o l l a r was 5,933.53 f t . The des ig - n a t e d "punchout" was t o occur w i t h i n a 5 - f t r a d i u s of N 20,447.31, E 52,709.41 a t an e l e v a t i o n of 6,049.03 f t ( f i g s . 15- 16). The l o c a t i o n of t h e boreho le was determined a f t e r c o n s i d e r i n g t h e geology of t h e r i g h t abutment and t h e c o n s t r a i n t s t h a t s p e c i f i c g e o l o g i c f e a t u r e s would i m - pose on t h e placement of t h e borehole . The abutment i n t h e v i c i n i t y of t h e bore- h o l e c o n s i s t s predominantly of coarse- to- medium-grained sands tone w i t h i n t e r b e d d e d s h a l e and s i l t s t o n e ( f i g . 15). The sand- s t o n e i s comprised mostly of ve ry hard a n g u l a r q u a r t z g r a i n s weakly t o moderate- l y cemented having an unconf ined compres- s i v e s t r e n g t h of l e s s t h a n 6 ,900 p s i (4 ) . The weak n a t u r e of t h e s a n d s t o n e ' s i n t e r - g r a n u l a r m a t e r i a l i n d i c a t e d t h a t t h e rock would probably d r i l l e a s i l y even though t h e s a n d s t o n e ' s q u a r t z g r a i n s were ve ry
and h o r i z o n t a l j o i n t s . U n f o r t u n a t e l y , t h e e x a c t l o c a t i o n s of t h e j o i n t s could n o t be determined because of t h i n s o i l cover , and t h u s t h e boreho le t r a j e c t o r y could n o t be planned t o avo id i n t e r c e p t - i n g them. However, t h e boreho le was de- s igned t o avo id i n t e r c e p t i n g t h e sand- f i l l e d j o i n t shown i n f i g u r e 15. The e l e v a t i o n a t t h e bottom of t h e sand- f i l l e d j o i n t was e s t i m a t e d t o be 5 ,950 f t , o r about 16.5 f t above t h e c o l l a r of t h e borehole . To p reven t d r i l l i n g i n t o t h e j o i n t , t h e f i r s t 250 f t of t h e demon- s t r a t i o n boreho le was t o be d r i l l e d keep- i n g boreho le e l e v a t i o n n e a r t h e e l e v a t i o n of t h e c o l l a r , o r 5 ,933 f t . D r i l l i n g was t o c o n t i n u e from 250 t o 340 f t , by apply- i n g maximum b u i l d and t o o l f a c e d i r e c - t i o n s of 0" t o 20" r i g h t and l e f t ( f i g . 10). A d e s i r e d i n c r e a s e i n boreho le in - c l i n a t i o n from 90.0" ( h o r i z o n t a l i n c l i n a - t i o n ) t o 101.0" (11.0" above h o r i z o n t a l ) would r e s u l t a t 300 t o 340 f t . Borehole
h a r d and a b r a s i v e . Rock o u t c r o p s w i t h i n i n c l i n a t i o n was t h e n t o be main ta ined a t t h e r i g h t abutment c o n t a i n both v e r t i c a l o r n e a r 101.0" t o boreho le complet ion i n
o r d e r t o i n t e r c e p t t h e t a r g e t e leva- s t r a i g h t - l i n e c o l l a r t o punchout t r a j e c - t i o n . While main ta in ing d e s i r e d v e r t i - t o r y having a bea r i ng of N 0"-45'-00" E c a l t r a j e c t o r y a s mentioned, an a t t empt was c a l c u l a t e d and appears i n appendix was t o be made t o main ta in depa r tu r e t a b l e A-2. This in format ion would be w i t h i n 2 f t e a s t o r west from t h e planned used cont inuously du r ing d r i l l i n g t o s t r a i g h t - l i n e c o l l a r t o punchout t r a j e c - monitor d e v i a t i o n from t h e d e s i r e d bore- t o r y ( f i g . 16). The depa r tu r e of t h e ho l e depar tu re .
DIRECTIONAL DRILLING THE DEMONSTRATION BOREHOLE
Seve ra l bent housings were used t o d r i l l t h e demons t ra t ion borehole ; t h e 2" ben t housing was t h e most e f f e c t i v e i n c o n t r o l l i n g v e r t i c a l and h o r i z o n t a l t r a - j e c t o r i e s ( f i g . 8 ) . Before d i s c u s s i n g t h e e f f e c t i v e n e s s of t h e ben t hous ings , t h e d r i l l i n g of t h e bo reho l e ' s v e r t i c a l and h o r i z o n t a l t r a j e c t o r i e s i s b r i e f l y descr ibed .
The f i r s t 250 f t of t h e borehole were d r i l l e d main ta in ing e l e v a t i o n nea r t h e c o l l a r e l e v a t i o n a s planned ( f i g . 17). D r i l l i n g con t inued t o a dep th of 495 f t w i thou t deve lop ing t h e necessa ry i n c r e a s e i n v e r t i c a l borehole t r a j e c t o r y . Conse- q u e n t l y , t h e borehole was abandoned i n o r d e r t o s t a r t a new borehole w i t h i n t h e i n i t i a l boreho le a t a dep th of 289 f t . A f t e r t h e new borehole was s t a r t e d a t 289 f t , d r i l l i n g con t inued t o borehole com- p l e t i o n a t 885 f t , main ta in ing d e s i r e d v e r t i c a l t r a j e c t o r y .
Hor izon ta l borehole t r a j e c t o r y du r ing t h e f i r s t 250 f t of t h e borehole was mainta ined t o w i t h i n 2.5 i t of t h e de- s i r e d depar tu re . (Table A-2 g ive s t h e a c t u a l borehole survey l o g and d e s i r e d borehole depar tu res . ) A s d r i l l i n g con- t i nued from 250 f t t o 495 f t , h o r i z o n t a l borehole t r a j e c t o r y dev i a t ed from t h e de- s i r e d course. A f t e r t h e new borehole was s t a r t e d a t 289 f t , h o r i z o n t a l t r a j e c t o r y of t h e new borehole was mainta ined c l o s e t o t h e d e s i r e d course t o borehole comple- t i o n , accord ing t o borehole surveys ( f i g . 18).
EFFECTIVENESS I N CONTROLLING BOREHOLE TRAJECTORY
The 112" bent housing w i th pad was used t o d r i l l t h e i n i t i a l borehole t o a dep th of 455 f t ( f i g . 19). Although t h e de- s i r e d v e r t i c a l and h o r i z o n t a l borehole
Target elevation.
1301 1 1 1 1 1 1 1 1 I I I I 1 1 1 1 1 1 1 1 I I I I 1 1 1 1 , , 6.0?;6.0?
HORIZONTAL DEPTH. f t
FIGURE 17.-Vertical section of demonstration borehole.
120
110-
l o o -
90-
C .I- 80-
i 70- 0 F 6 0 - P
5 0 - W
40
3 0
2 0 -
- I 0 0
-
-
- KEY
Surveyed elevation station - of Initial borehole -
- A Surveyed elevation station - of new borehole, sidetracked
- from initial borehole - -
- Collar elevation, 5,933.53 f t
-
o.*-f . - . - - - - - - - = -.-
~ ~ ~ ~ ~ ~ ~ ~ ' ~ ~ ' ~ ' ~ ~ ~ ~ ~ ~ " ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ l ~ l l l l l l l l l l
100 2 0 0 300 400 5 0 0 6 0 0 700 800 900
- 4 - " " 1 " I , , , I I I I
-2 -
Actual punchout, measured
boundary of 5-ft - radius target
10-
12-
LATITUDE, f t 8 FIGURE 18.-Plan view of demonstration borehole. Abandoned borehole from 279 to 495 ft not shown. Before drilling of side-
tracked borehole began a t 289 ft, initial borehole resurveyed from 89 to 279 ft at 30-ft intervals as shown.
FIGURE 19.-Various bent housings. Top to bottom: 2' bent housing on in-hole motor, slip-on shoe, lo bent housing with pad, 112" bent housing with pad.
t r a j e c t o r i e s were maintained t o a depth of 250 f t , t h e v e r t i c a l and h o r i z o n t a l d e f l e c t i o n r a t e s were i n c o n s i s t e n t and unpredic tab le . D r i l l i n g continued t o a dep th of 455 f t without success i n bring- i n g t h e v e r t i c a l and h o r i z o n t a l borehole t r a j e c t o r i e s t o t h e d e s i r e d course. The i n c o n s i s t e n t d e f l e c t i o n r a t e s caus ing poor t r a j e c t o r y c o n t r o l r e s u l t e d from a
lack of s u f f i c i e n t s i d e f o r c e being gen- e r a t e d while u s ing t h e 112' bent housing. The weak n a t u r e of t h e sands tone ' s i n t e r - g r anu la r ma te r i a l i s bel ieved t o have ne- ga ted any p o t e n t i a l s i d e f o r c e generated by t h e 112' bent housing. A t a depth of 455 f t , t h e d r i l l s t r i n g and in-hole mo- t o r were pu l l ed ou t of t he borehole t o r ep l ace t h e 112" housing with a l o bent
h o u s i n g , a f t e r i t became a p p a r e n t t h a t t h e n e c e s s a r y i n c r e a s e i n e l e v a t i o n of 112 f t and change i n d e p a r t u r e of 14 f t e a s t r e q u i r e d t o i n t e r c e p t t h e t a r g e t c o u l d n o t be accomplished u s i n g t h e 112" b e n t housing.
D r i l l i n g con t inued from 455 f t t o a d e p t h of 495 f t u s i n g t h e 1" ben t hous ing w i t h pad ( f i g . 19). Even though t h e ve r - t i c a l d e f l e c t i o n r a t e s were more c o n s i s - t e n t when compared t o t h e 112" ben t hous- i n g , t h e h o r i z o n t a l boreho le t r a j e c t o r y c o n t i n u e d west i n s t e a d of e a s t . A t t h e s u r v e y d e p t h of 479 f t ( b i t d e p t h of 495 f t ) , t h e boreho le was c a l c u l a t e d t o be 16.8 f t west of t h e t a r g e t d e p a r t u r e and 96.0 f t below t a r g e t e l e v a t i o n . Conse- q u e n t l y , i t was dec ided t o abandon t h e b o r e h o l e and t o s i d e t r a c k o r s t a r t a new b o r e h o l e from w i t h i n t h e i n i t i a l boreho le a t a d e p t h of 289 f t . A s w i t h t h e 112" b e n t hous ing , t h e 1' ben t hous ing appar - e n t l y f a i l e d t o g e n e r a t e s u f f i c i e n t s i d e f o r c e t o c o n t r o l boreho le t r a j e c t o r y .
To accommodate t h e s i d e t r a c k a t a d e p t h of 289 f t , enough d r i l l rod was removed f rom t h e boreho le t o p o s i t i o n t h e d r i l l b i t a t a dep th of 275 f t , t o beg in t h e s i d e t r a c k . The s i d e t r a c k i n g procedure h a s been d e s c r i b e d i n a p r e v i o u s Bureau of Mines p u b l i c a t i o n ( 2 ) . - Using t h e i n - h o l e motor equipped w i t h t h e 1" ben t h o u s i n g , t h e s i d e t r a c k was s t a r t e d a t a d e p t h of 275 f t and completed a t a bore- h o l e d e p t h of 289 f t ( f i g . 17). The i n i - t i a l b o r e h o l e was a l s o resurveyed from 89 t o 289 f t , p r i m a r i l y f o r b e a r i n g , a f - t e r r e p l a c i n g a d e f e c t i v e muleshoe and c e n t r a l i z i n g pumpdown washers t h a t were b e l i e v e d t o have caused e r r o r i n measur- i n g b o r e h o l e b e a r i n g ( t a b l e A-2, f i g u r e 13) .
D r i l l i n g of t h e new boreho le resumed f rom 289 f t t o a d e p t h of 385 f t a f t e r t h e 1' hous ing was r e p l a c e d w i t h a 2" h o u s i n g equipped w i t h a s l i p - o n s h o e (po- s i t i o n e d on t h e i n - h o l e motor a t t h e apex of t h e 2' ben t hous ing) ( f i g . 19) . De- s i r e d b o r e h o l e i n c l i n a t i o n and e l e v a t i o n were a t t a i n e d a t a dep th of 329 f t a f t e r o n l y 40 f t of d r i l l i n g w i t h t h e 2' hous- i n g and s l i p - o n shoe and were main ta ined t h e r e a f t e r . By r e f e r r i n g t o t h e a c t u a l b o r e h o l e su rvey l o g and t h e d e s i r e d
boreho le d e p a r t u r e s i n t a b l e A-2, i t can be s e e n t h a t h o r i z o n t a l t r a j e c t o r y was r e t u r n e d t o and c o n t r o l l e d w i t h i n 2 f t of t h e d e s i r e d boreho le d e p a r t u r e ( f i g . 18) . C o n t r o l on both v e r t i c a l and h o r i z o n t a l boreho le t r a j e c t o r i e s was accomplished f o r t h e f i r s t t ime because t h e t o o l f a c e s e t t i n g s r e s u l t e d i n p r e d i c t a b l e and con- s i s t e n t d e f l e c t i o n r a t e s . While d r i l l i n g w i t h t h e 2" housing and s l ip -on shoe , compared t o t h e p r e v i o u s bent h o u s i n g s , t h e s i d e f o r c e g e n e r a t e d was g r e a t enough t o overcome t h e weak n a t u r e of t h e sand- s t o n e ' s i n t e r g r a n u l a r m a t e r i a l . Although d i r e c t i o n a l c o n t r o l had improved, t h e s l i p - o n shoe f r e q u e n t l y go t s t u c k i n t h e boreho le w h i l e d r i l l i n g , caus ing t h e average p e n e t r a t i o n r a t e t o d e c r e a s e t o 7 in /min from 21 in /min w i t h t h e p r e v i o u s housings . There fo re , a t a dep th of 385 f t , t h e d r i l l rods and in-hole motor were removed from t h e boreho le t o remove t h e s l i p - o n shoe from t h e 2" bent housing.
The demonstra t i o n boreho le was com- p l e t e d t o t h e f i n a l boreho le dep th of 885 f t u s i n g t h e 2' ben t housing wi thou t t h e s l i p - o n shoe ( f i g u r e s 8 and 19). Ac- t u a l d e f l e c t i o n r a t e s were c o n s i s t e n t and p r e d i c t a b l e f o r d i r e c t i o n a l c o n t r o l w i t h t h e 2" housing ( t a b l e 1 ) . The h o r i z o n t a l boreho le t r a j e c t o r y was main ta ined w i t h i n 2 f t e a s t o r west of t h e des igned t r a j e c - t o r y excep t f o r a s h o r t i n t e r v a l around 500 f t ( f i g . 18). Borehole e l e v a t i o n o r v e r t i c a l t r a j e c t o r y i n c r e a s e d a t an a v e r - age r a t e of 1.98 f t p e r 10 f t d r i l l e d , m a i n t a i n i n g a n average boreho le i n c l i n a - t i o n of approximate ly 101.0" t o s u c c e s s - f u l l y i n t e r c e p t t h e d e s i g n a t e d t a r g e t e l e v a t i o n ( f i g . 17).
BOREHOLE PUNCHOUT AND INVESTIGATING ERROR I N AZIMUTH
The a c t u a l demons t ra t ion punchout d e p t h was 885 f t a t e l e v a t i o n 6,047.53, 1.50 f t below t a r g e t c e n t e r and 8.81 f t s o u t h - west of t h e t a r g e t p e r i m e t e r o r 13.81 f t sou thwes t of t a r g e t c e n t e r ( f i g . 20). The t a r g e t e d punchout was t o occur w i t h i n a 5 - f t r a d i u s w i t h c e n t e r c o o r d i n a t e s of N 20,447.31, E 52,709.41 a t e l e v a t i o n 6,049.03 f t . The c a l c u l a t i o n s from t h e NL Sperry-Sun s u r v e y s showed t h e punchout
TABLE 1. - Measured d e f l e c t i o n r a t e s u s i n g 2" bent hous ing , d e g r e e s p e r f o o t
Tool f a c e s e t t i n g
Righ t : 20" t o 40°..... 40" t o 60°..... 60" t o 80°..... 80" t o 100°.... 100" t o 120°... 120" t o 140°... 140" t o 160°...
L e f t : 0 0 t o 20 o ~ . . . . .
40" t o 60°..... 60" t o 80°..... 80" t o 100°.... 100" t o 120°... 120" t o 140°... 140" t o 160°... NAp Not a p p l i c
Change i n i n c l i n a t i o n ( v e r t i c a l ) l
Range
Change i n b e a r i n g I ( h o r i z o n t a l )
Average
- 0 0 3 t o +.09 - 0 0 1 t o +.06 - 0 1 2 t o +.06 - 0 1 2 t o +.04
NAp -.07 t o - 0 2 0
NAp
Range I Average I
- 0 0 3 +. 05 - 0 0 2 - 0 0 4 - 0 1 3 - 0 1 2 -. 16
.30L- .11R
.52L- .OOR m4OL- .02L m13L- .59L
NAP m53L- 00 1R
NAp ble . ' + I n c r e a s e ( b u i l d u p ) ; - d e c r e a s e (d rop) .
'R Right ( e a s t ) ; L L e f t (wes t ) . 3 ~ e f t t o o l f a c e s e t t i n g s were a p p l i e d from 805- t o 885-ft
boreho le depth . During t h a t d r i l l i n g i n t e r v a l , t h e n e c e s s a r y b i t t h r u s t of >7 ,000 l b was n o t r e a d i l y a v a i l a b l e . Conse- q u e n t l y , d r i l l i n g p e n e t r a t i o n r a t e s and d e f l e c t i o n magnitudes dec reased .
t o be a t e l e v a t i o n 6,047.14 f t 1.89 f t below t h e t a r g e t c e n t e r , and a t coord i - n a t e s N 20,439.96, E 52,710.80, 1.4 f t n o r t h e a s t of t h e t a r g e t c e n t e r . The e l e - v a t i o n e r r o r between t h e a c t u a l and c a l - c u l a t e d punchout was 0.39 f t , which was w e l l w i t h i n t h e accuracy of t h e su rvey i n s t r u m e n t . The c o o r d i n a t e e r r o r between t h e a c t u a l and c a l c u l a t e d punchout was 15.20 f t ( f i g u r e s 18 and 20) , which was w i t h i n t h e 1" accuracy of t h e s u r v e y i n - s t r u m e n t i n measur ing bea r ing .
I n v e s t i g a t i o n i n t o c a l c u l a t i n g system- a t i c compass e r r o r caused by d r i l l s t r i n g i n t e r f e r e n c e h a s i n d i c a t e d t h a t a p o s s i - b l e e r r o r of 0.30" E was imposed on t h e compass (11) . Applying t h e e q u a t i o n de- ve loped b y ~ l ~ t h e and C a l l a s ( 1 1 ) - f o r e s - t imat i n g compass s p a c i n g ,
C = s i n - ' ( ( F / H ) ( s i n ( 1 ) s i n (EN),
where C = compass c o r r e c t i o n , ",
F = n e t f o r c e s a f f e c t i n g compass, EMU,
H = h o r i z o n t a l component of e a r t h ' s magnet ic f i e l d i n t e n - s i t y (23,300 nT o r 0.0233 EMU a t Navajo Dam, a c c o r d i n g t o t h e Na t iona l Geophysical Data C e n t e r ) ,
I = boreho le i n c l i n a t i o n , 95",
and E = compass r e a d i n g , 350".
FIGURE 20.-Borehole punchout.
where PL = lower po l e s t r e n g t h , esti- mated a t 100 EMU,
PU = upper po le s t r e n g t h , e s t i - mated a t 1,000 EMU,
DL = compass d i s t a n c e from lower po le , 400 cm,
and DU = compass d i s t a n c e from upper po le , 3,020 cm.
C = -0.30' ( c o r r e c t i o n of 0.30° W).
A f i n a l punchout depar ture of 52,706.16 E was ca l cu l a t ed by applying the compass e r r o r c o r r e c t i o n t o t h e previously sur- veyed borehole bear ings. This depar ture i s 4.61 f t c l o s e r t o t h e a c t u a l punchout a s compared t o not applying t h e compass cor rec t ion . Although caut ion must be used when c a l c u l a t i n g compass c o r r e c t i o n caused by d r i l l s t r i n g i n t e r f e r e n c e , be- cause po le s t r e n g t h s cannot be measured p r e c i s e l y and a r e no t cons tan t , t h e ca l - c u l a t i o n i n t h i s a p p l i c a t i o n ' would have increased borehs le punchout accuracy.
CONCLUSIONS
The demonstra t ion borehole was d i r e c - ins t rument . The 2" bent housing was t h e t i o n a l l y d r i l l e d t o a f i n a l d e p t h of 885 most e f f e c t i v e i n main ta in ing d i r e c t i o n a l f t , where punchout occurred. F i n a l bore- c o n t r o l of t h e v e r t i c a l and h o r i z o n t a l h o l e e l e v a t i o n was w e l l w i t h i n t h e t a r - boreho le t r a j e c t o r i e s . g e t ; boreho le punchout c o o r d i n a t e s were A s a r e s u l t of t h e demonstrated bore- 8.81 f t southwest of t h e t a r g e t . Bore- h o l e d r i l l i n g accuracy , t h e o r i g i n a l p l a n h o l e s can only be d i r e c t i o n a l l y d r i l l e d of c o n s t r u c t i n g a long t u n n e l under t h e w i t h i n t h e accuracy of t h e boreho le s u r - r i g h t abutment of Navajo Dam and d r i l l i n g vey system used. The NL Sperry-Sun t y p e 150-ft boreholes from i n s i d e t h e t u n n e l B 120" s i n g l e - s h o t d i r e c t i o n a l su rvey i n - t o c o n t r o l wa te r seepage was abandoned. s t rument is a c c u r a t e t o w i t h i n 1" b e a r i n g The Bureau of Reclamation has i n s t e a d and 0.24" i n c l i n a t i o n . The borehole- c o n t r a c t e d t h e c o n s t r u c t i o n of a s h o r t e r surveyed punchout, r e l a t i v e t o t h e land- t u n n e l and t h e a c c u r a t e d r i l l i n g of bore- su rveyed a c t u a l punchout, was w i t h i n t h e h o l e s a s long a s 600 f t , r e s u l t i n g i n a accuracy of t h e NL Sperry-Sun survey s u b s t a n t i a l c o s t sav ings t o t h e taxpayer .
REFERENCES
1. Oyle r , D. C . , and W. P. Diamond. D r i l l i n g a H o r i z o n t a l Coalbed Methane Drainage System From a D i r e c t i o n a l Sur- f a c e Borehole. BuMines R I 8640, 1982, 50 PP.
2. K r a v i t s , S. J . , A. S a i n t o , and G. L. F i n f i n g e r . Comparison of Rotary and In-Hole Motor Techniques f o r D r i l l i n g H o r i z o n t a l Boreholes i n Coal. BuMines R I 8933, 1985, 33 pp.
3. . The Advantages of In-Hole Motor D r i l l i n g . Coal Min., v. 21, No. 11, 1984, pp. 44-46.
4, E h l e r , W. C. F i n a l Report on In- v e s t i g a t i o n s f o r Seepage C o n t r o l Navajo Dam. U. S. BuReclamation (Dep. I n t e r i o r ) , 1983, 48 pp.
5. P i t t a r d , F. High Torque 2-718-in- OD In-Hole Motor Performance Data. Slim- d r i l Inc . , Houston, TX, 1984, 21 pp.
6. American Petroleum I n s t i t u t e . D i - r e c t i o n a l D r i l l i n g Survey C a l c u l a t i o n
Methods and Terminology. Bul l . D20, Dec. 1985, 31 pp.
7. NL Sperry-Sun (Oklahoma C i t y , OK). Magnetic D i r e c t i o n a l Single-shot Operat- i n g I n s t r u c t i o n s . 1972, 12 pp.
8. Wolff , C. J. M . , and J. P. deWardt. Borehole P o s i t i o n U n c e r t a i n t y Ana lys i s of Measuring Methods and Deriva- t i o n of Sys temat ic E r r o r Model. J. Pet . Technol. , v. 33, 1981, pp. 2339-2350.
9, B ly the , E. J., Jr. E s t i m a t i n g Compass Spacing I n s i d e Nonmagnetic C o l l a r s . D r i l l i n g - DCW, v. 36, 1975, pp. 44-47.
10. F i t c h a r d , E. E. Randomly Simu- l a t e d Borehole T e s t s Accuracy of Direc- t i o n a l Survey Methods. O i l and Gas J. , v. 79, No. 26, 1981, pp. 140-150.
11. B ly the , E. J. , Jr, , and N. P. Cal- l a s . Procedure Improves P l a t f o r m Well Loca t ion Technique. O i l and Gas J., v. 75, No. 18, 1977, pp. 224-232.
APP
EN
DIX
.--D
RIL
L
AN
D
BORE
HO
LE SU
RVEY
LOGS
TAB
LE
A-1
. -
Log
o
f d
ire
cti
on
al
dri
llin
g p
ara
me
ters
Dat
e.
I Bo
reh
ole
I In
tak
e w
ate
r I
Bi t
I
Bit
1
98
5:
1 de;;h,
Se
pt.
. 1
9..
..
Oct
. :
4.b
..
4.b
..
7.b
..
7.b
..
8..
..
11
.b..
1
9..
..
19
....
20
. . . .
2
0..
..
20
.b..
2
0..
..
22. . . .
22
r 2
2.b
..
22
.b..
2
3..
..
23
.. . .
23
....
2
3..
..
23
....
2
3..
..
23
.,..
2
3..
..
23
.,..
2
4..
..
24
.,..
2
4..
..
24
....
2
4..
..
24
.. ..
rota
tio
n,
r/m
in
torq
ue
, f
tblb
f
NAp
I NA
p I
NAp
1 NAp
1 3-l/Z
-in
re
amed
to
6-i
n
ID.
Su
rvey
ti
me
, m
i n
Lo
st
cir
cu
lati
on
.
Com
men
ts
Co
mp
lete
d
dy
e te
st.
R
egai
ned
c
irc
ula
tio
n.
Lo
st
pa
rtia
l c
irc
ula
tio
n.
Do.
Do
. D
o.
Do .
Do .
Do.
Do
. D
o.
Do .
Re
turn
wa
ter
flo
w
inc
rea
sed
. D
o.
Do .
NAp
Not
a
pp
lic
ab
le.
'~h
ru
st
forc
e =
Th
rust
p
ress
ure
(b
ars
) x
14.7
p
sig
/ba
r x
1.2
68
in
2 (
pis
ton
are
a).
TAB
LE
A-1
. -
Log
of
d
ire
cti
on
al
dri
llin
g p
aram
eter
s--C
on
tin
ued
Com
men
ts
Re
turn
wa
ter
flo
w
inc
rea
sed
. O
utp
ut
flo
w e
xce
eded
in
pu
t.
Ou
tpu
t fl
ow
>
70
gpm
.
80-g
pm
ou
tflo
w.
Ins
tall
ed
1"
ho
usi
ng
.
Sid
etr
ac
ke
d a
t 28
9 f
t.
Ins
tall
ed
2
" w
ith
sh
oe.
S
urv
ey
ing
pro
ble
ms.
10
0-gp
m
ou
tpu
t.
Rem
oved
sl
ip-o
n
sho
e.
Co
nd
uct
ed
2 s
urv
ey
s.
Da
te,
19
85
Oct
.:
24
.. . .
24. ...
2
5..
..
25
.. . .
25. .. .
25
.. ..
25. .. .
25
.. ..
25. ...
25
. ...
2
5..
..
26
....
3
0..
. .
30
....
3
0..
..
30. ...
N
ov. :
l...
. 4
....
5
....
6
....
6
....
6.
.. .
7..
..
7..
..
7..
..
7..
..
7..
..
8..
..
8..
..
go
...
9..
..
9..
..
9..
..
9..
..
9. ..
. 9
....
9
....
9
....
Bo
reh
ole
d
ep
th,
f t
35
5
36
5
37
5
38
5
39
5
40
5
41
5
42
5
43
5
44
5
45
5
NAp
46
5
47
5
48
5
49
5
NA
p NA
p NA
p 3
05
3
15
3
25
3
35
3
45
3
55
3
65
3
75
3
85
NA
p 3
95
4
05
4
15
4
25
4
35
4
45
4
55
46
5 4
75
Inta
ke
gp
m
67
67
67
67
67
67
65
6
5
68
68
6
8
NAp 63
62
62
6
8
NAp
NAp
NAp 65
66
67
66
66
6
5
69
6
5
67
NAp 68
66
6
5
66
65
66
67
66
66
Bit
ro
tati
on
, r/
min
81
3
81
3
81
3
81
3
81
3
81
3
78
5
785
82
5
82
5
82
5
NAP
746
7 30
7
30
82
5
NA
P N
AP
NAP
78
5
80
0
8 1
3
80
0
80
0
785
83
9
785
81
3
NA
P 8
25
8
00
78
5 8
00
7
85
8
00
8 1
3
80
0
80
0
wa
ter
psi
g
60
0
60
0
60
0
60
0
575
50
0
55
0
500
55
0
62
5
62
5
NAp
65
0
60
0
700
700
NAp
NAp
NAp
65
0
65
0
65
0
65
0
550
60
0
60
0
60
0
550
NAp
500
52
5
550
500
55
0
510
510
60
0
550
Bit
to
rqu
e,
ft0
lbf
11
0
11
0
11
0
11
0
10
0
90
9
5
90
9
5
11
0
110
NAP
11
5
11
0
12
5
12
5
NAP
NA
P NA
P 1
70
17
6 1
78
17
6 17
6 15
6 16
6 1
56
1
48
N
AP
90
9
0
95
9
0
95
9
0
90
11
0 9
5
Th
rust
p
ress
ure
, b
ars
245
245
235
245
250
255
255
250
250
250
250
NA
P 25
0 25
0 25
0 25
0
NAP
NAP
NAP
250
250
250
230
250
260
250
250
260
NAP
260
275
295
290
30
5
300
295
310
300
Th
rust
' fo
rce
, lb
f
4,5
67
4
,56
7
4,3
80
4
,56
7
4,6
60
4
,75
3
4,7
53
4
,66
0
4,6
60
4
,66
0
4,6
60
NA
P 4
,66
0
4,6
60
4
,66
0
4,6
60
NAP
NA
P NA
P 4
,66
0
4,6
60
4
,66
0
4,2
87
4
,66
0
4,8
46
4
,66
0
4,6
60
4
,84
6
NA
P 4
,84
6
5,1
26
5
,49
9
5,4
06
5
,68
5
5,5
92
5
,49
9
5,7
78
5
,59
2
Dr
ill
tim
e,
10
-ft
rod
, m
i n 3
4 3
4
4
4
5
6
3
3
4
NAP 3
3
3
3
NAP
NAP
NAP 2 1
28
1
3
9
13
8
31
2
1
25
NA
P 5
5
4
5
6 5
5
6
5
Su
rvey
ti
me
, m
i n
31
33
1
39
5
7
49
50
35
67
31
40
31
NA
P 42
39
3 1
36
NAp
NAp
NAp 32
47
19
30
30
2
1
32
3 2
30
NAp 23
42
28
45
59
22
26
19
22
NAp
Not
a
pp
lic
ab
le.
'~h
ru
st
for
ce
= T
hru
st
pre
ssu
re
(ba
rs)
Su
rvey
ing
pro
ble
ms.
C
ond
uct
ed
2 s
urv
eys.
D
o.
Do.
Do.
Do.
Rep
aire
d
surv
ey h
ard
war
e.
Use
d
a w
inch
, +
1,0
00
lb.
Do.
D
o.
Do.
D
o.
Do.
D
o.
Do.
D
o.
Do.
D
o.
Do.
14.7
p
sig
/ba
r x
1.2
68
in
2 (
pis
ton
are
a).
TAB
LE
A-2
. -
Dem
on
stra
tio
n b
ore
ho
le s
urv
ey
lo
g a
nd
lo
g o
f d
esi
red
de
pa
rtu
res
Bo
re-
ho
le
de
pth
, f
t
NA
P NA
P N
AP
NAP
NAP 65
7
5
85
9
5
10
5
11
5
12
5
13
5
14
5
15
5
16
5
17
5
18
5
19
5
20
5
21
5
22
5
235
24
5
25
5
26
5
27
5
28
5
Azi
mu
th
(un
cor-
re
cte
d),
d
eg
l
NA
P N
AP
35
0.8
1
NA
P NA
P 34
9.50
3
48
.25
34
8.50
35
0.50
35
1.50
3
52
.86
3
50
.70
3
51
.20
35
1.00
34
8.90
34
9.50
34
8.47
35
0.36
34
7.70
3
47
.90
34
8.40
34
8.70
34
8.00
34
5.70
34
7.00
3
45
.50
34
6.30
3
44
.80
Su
rvey
d
ep
th,
ft
0
6
16
26
36
49
59
6
9
79
89
9
9
10
9
119
12
9
13
9
14
9
15
9
16
9
17
9
18
9
19
9
209
219
229
239
249
259
269
Bo
reh
ole
in
cli
- n
ati
on
, d
eg
90.0
8
7.9
8
8.0
8
7.5
88
.9
88.9
8
9.5
90
.0
90.4
90
.9
91.0
91
.4
91.0
90
.5
90.6
90
.7
91.0
91
.5
89.7
89
.2
89
.5
89.9
90
.0
90.1
90
.0
90.0
90
.5
91.1
Cha
nge
in
dep
ar-
ture
s ,
ft
N
AP
NAP
0.3
9
NA
P N
AP
1.24
.1
5
.06
.2
6
.52
.7
3
.66
.5
1
.54
.3
1
.17
.17
.25
.1
8
-.0
3
.03
.l
o
.06
-.
20
-.
29
-.
31
-.
37
-.
43
La
titu
de
, f
t
19
,56
7.6
9
NAp
19
,58
3.6
8
NAp
NAp
19
,61
6.6
4
19
,62
6.6
4
19
,63
6.6
4
19
,64
6.6
3
19
,65
6.6
2
19
,66
6.5
9
19
,67
6.5
7
19
,68
6.5
5
19
,69
6.5
4
19
,70
6.5
3
19
,71
6.5
3
19
,72
6.5
3
19
,73
6.5
2
19
,74
6.5
2
19
,75
6.5
2
19
,76
6.5
2
19
,77
6.5
1
19
,73
6.5
1
19
,79
6.5
1
19
,80
6.5
1
19
,81
6.5
0
19
,82
6.5
0
19
,83
6.4
8
Cha
nge
in
lati
- tu
de
s ,
ft
NA
P NA
P 15
.99
NA
P N
AP
32.9
6 9.
99
9.99
9.
99
9.9
8
9.97
9.
97
9.9
8
9.9
8
9.99
9.
99
9.99
9.
99
9.99
9.
99
9.99
9.
99
9.99
9.
99
9.99
9.
99
9.99
9.
99
Cha
nge
in t
rue
v
ert
ica
l d
ep
th,
ft
NA
p 0
.11
.3
6
.39
.3
1
019
.14
00
4 -0
03
-0
11
-0
17
-0
21
-.
21
-.
13 -. 10
-01
1
-.1
5
-. 22 -. 10 .lo
.1
1
.05
.0
1
-.0
1
-.0
1
.OO
-0
04
-0
14
Co
rres
- p
on
din
g
de
pth
, f
t4
0
10
20
30
40
50
60
70
80
90
100
110
12
0
130
140
150
160
170
18
0
190
200
210
220
230
240
250
260
270
Tru
e v
ert
ica
l d
ep
th,
ft2
-5,9
33
.53
-5
,93
3.4
2
-5,9
33
.06
-5
,93
2.6
7
-5,9
32
.36
-5
,93
2.1
7
-5,9
32
.03
-5
,93
1.9
9
-5,9
32
.02
-5
,93
2.1
4
-5,9
32
.30
-5
,93
2.5
1
-5,9
32
.72
-5
,93
2.8
5
-5,9
32
.95
-5
,93
3.0
6
-5,9
33
.21
-5
,93
3.4
3
-5,9
33
.53
-5
,93
3.4
4
-5,9
33
.33
-5
,93
3.2
7
-5,9
33
.26
-5
,93
3.2
7
-5,9
33
.28
-5
,93
3.2
8
-5,9
33
.32
-5
,93
3.4
6
Dep
artu
re,
ft
52
,69
7.7
9
NA
P 5
2,6
98
.18
NA
P NA
P 5
2,6
99
.42
5
2,6
99
.57
5
2,6
99
.64
5
2,6
99
.90
5
2,7
00
.42
5
2,7
01
.15
5
2,7
01
.81
5
2,7
02
.33
5
2,7
02
.87
5
2,7
03
.18
5
2,7
03
.35
5
2,7
03
.52
5
2,7
03
.77
5
2,7
03
.95
5
2,7
03
.91
5
2,7
03
.94
5
2,7
04
.04
5
2,7
04
.10
5
2,7
03
.90
5
2,7
03
.61
5
2,7
03
.30
5
2,7
02
.94
5
2,7
02
.51
Des
ired
d
epar
- tu
res
, ft3
52
,69
7.7
9
52
,69
7.4
2
52
,69
8.0
6
52
,69
8.1
9
52
,69
8.3
2
52
,69
8.4
5
52
,69
0.5
8
52
,69
8.7
2
52
,69
8.8
5
52
,69
8.9
8
52
,69
9.1
1
52
,69
9.2
5
52
,69
9.3
8
52
,69
9.5
1
52
,69
9.6
4
52
,69
9.7
8
52
,69
9.9
1
52
,70
0.0
4
52
,70
0.1
7
52
,70
0.3
0
52
,70
0.4
4
52
,70
0.5
7
52
,70
0.7
0
52
,70
0.8
3
52
,70
0.9
6
52
,70
1.1
0
52
,70
1.2
3
52
,70
1.3
6
See
fo
otn
ote
s a
t en
d
of
tab
le.
TAB
LE
A-2
. -
De
mo
nst
rati
on
bo
reh
ole
su
rve
y l
og
an
d
log
of
de
sire
d
dep
artu
res-
-Co
nti
nu
ed
Bo
re-
ho
le
de
pth
, f
t
34
5
35
5
36
5
37
5
38
5
39
5
40
5
4 1
5
42
5
43
5
44
5
45
5
46
5
47
5
48
5
49
5
50
5
51
5
52
5
53
5
54
5
55
5
56
5
57
5
58
5
59
5
60
5
61
5
62
5
Bo
reh
ole
in
cli
- n
ati
on
, d
eg
10
0.9
1
00
.4
99
.9
98
.2
10
0.3
1
03
.5
10
2.9
1
00
.9
10
1.0
1
00
.0
10
0.0
1
00
.0
10
0.4
1
01
.3
10
1.9
1
03
.1
10
2.8
1
02
.1
10
2.9
1
03
.5
10
3.5
1
02
.5
10
0.9
1
01
.0
10
0.3
1
00
.7
10
0.8
1
01
.4
10
1.0
Su
rvey
d
ep
th,
ft
32
9
33
9
34
9
35
9
369
37
9
38
9
399
409
419
429
439
449
459
469
479
489
499
50
9
5 1
9
529
539
54
9
559
56
9
579
58
9
59
9
60
9
Azi
mu
th
(un
co
r-
rec
ted
),
de
gl
34
7.9
0
35
2.5
5
34
9.6
0
34
4.4
0
34
7.5
0
35
1.2
0
35
2.5
0
34
6.7
0
34
6.7
0
34
6.8
0
34
6.5
0
34
3.3
0
33
8.1
4
34
0.0
0
34
1.2
0
34
4.8
0
34
6.3
0
34
7.6
0
34
8.7
0
35
0.0
0
35
4.9
0
35
3.3
0
35
2.2
0
35
5.0
0
35
5.1
0
35
3.8
0
35
3.8
0
Cha
nge
in
de
pa
r-
ture
s ,
ft
-0
.46
.3
8
.53
-.
I7
-.3
5
.23
.6
5
.27
-.
22
-.
21
-.
23
- . 5
3
-1.2
5
-1.5
2
-1.2
6
-.8
5
-.4
2
-.I8
.0
3
.23
.7
5
1.0
4
.81
-9
6
1.2
1
1.1
0
.99
.9
4
35
0.5
0
Cha
nge
in
lati
-
tud
es ,
ft
9
.81
9
.82
9
.83
9.
87
9.8
6
9.7
8
9.7
1
9.7
8
9.8
1
9.8
3
9.8
4
9.8
3
9.7
6
9.7
0
9.7
1
9.7
2
9.7
4
9.7
6
9.7
6
9.7
3
9.6
9
9.6
9
9.7
6
9.7
7
9.7
5
9.77
9.
77
9.7
7
9.7
9
Cha
nge
in t
rue
v
ert
ica
l d
ep
th,
ft
-1
.72
-1
.85
-1
.76
-1
.57
-1
.61
-2
.06
-2
.28
-2
.06
-1
.90
-1
.83
-1
.75
-1
.74
-1
.77
-1
.88
-2
.01
-2
.16
-2
.24
-2
.16
-2
.16
-2
.28
-2
.33
-2
.25
-2
.03
-1
.90
-1
.85
- 1
.82
-1
.87
-1
.93
-1
.94
De
pa
rtu
re,
ft
52
,70
3.5
5
52
,70
3.9
3
52
,70
4.4
6
52
,70
4.2
9
52
,70
3.9
3
52
,70
4.1
6
52
,70
4.8
2
52
,70
5.0
9
52
,70
4.8
7
52
,70
4.6
5
52
,70
4.4
2
52
,70
3.8
9
52
,70
2.6
4
52
,70
1.1
1
52
,69
9.8
5
52
,69
9.0
0
52
,68
9.5
8
52
,69
8.4
0
52
,69
8.4
3
52
,69
8.6
5
52
,69
9.4
1
52
,70
0.4
4
52
,70
1.2
6
52
,70
2.2
2
52
,70
3.4
2
52
,70
4.5
2
52
,70
5.5
2
52
,70
6.4
6
52
,70
7.1
2
La
titu
de
, f
t
19
,89
5.9
3
19
,90
5.7
5
19
,91
5.5
8
19
,92
5.4
5
19
,93
5.3
1
19
,94
5.0
9
19
,95
4.8
0
19
,96
4.5
8
19
,97
4.3
9
19
,98
4.2
2
19
,99
4.0
7
20
,00
3.9
0
20
,01
3.6
6
20
,02
3.3
6
20
,03
3.0
7
20
,04
2.8
0
20
,05
2.5
3
20
,06
2.3
0
20
,07
2.0
6
20
,08
1.8
0
20
,09
1.4
9
20
,10
1.1
8
20
,11
0.9
3
20
,12
0.7
0
20
,13
0.4
6
20
,14
0.2
3
20
,15
0.0
0
20
,15
9.7
7
20
,16
9.5
6
Tru
e v
ert
ica
l d
ep
th,
ft
2
-5,9
38
.48
-5
,94
0.3
3
-5,9
42
.09
-5
,94
3.6
7
-5,9
45
.27
-5
,94
7.3
4
-5,9
49
.62
-5
,95
1.6
8
-5,9
53
.58
-5
,95
5.4
1
-5,9
52
.14
-5
,95
8.8
9
-5,9
60
.64
-5
,96
2.5
3
-5,9
64
.54
-5
,96
6.7
1
-5,9
68
.95
-5
,97
1.1
0
-5,9
73
.26
-5
,97
5.5
5
-5,9
77
.88
-5
,98
0.1
3
-5,9
82
.16
-5
,98
4.0
6
-5,9
85
.91
-5
,98
7.7
3
-5,9
89
.60
-5
,99
1.5
2
-5,9
93
.46
De
sire
d
de
pa
r-
ture
s ,
ft
3
52
,70
2.1
4
52
,70
2.2
7
52
,70
2.4
0
52
,70
2.5
3
52
,70
2.6
6
52
,70
2.7
9
52
,70
2.9
2
52
,70
3.0
5
52
,70
3.1
8
52
,70
3.3
1
52
,70
3.4
4
52
,70
3.5
7
52
,70
3.7
0
52
,70
3.8
3
52
,70
3.9
6
52
,70
4.0
9
52
,70
4.2
2
52
,70
4.3
5
52
,70
4.4
8
52
,70
5.6
1
52
,70
5.7
4
52
,70
5.8
7
52
,70
6.0
0
52
,70
6.1
3
52
,70
6.2
6
52
,70
6.3
9
52
,70
6.5
2
52
,70
6.6
5
Co
rre
s-
po
nd
ing
d
ep
th,
ft
4
33
0
340
350
360
37
0
380
39
0
400
410
420
430
440
450
46
0
470
48
0
49
0
500
510
520
530
540
550
560
570
580
59
0
60
0
52
,70
6.7
8
610
635
645
655
665
675
685
595
705
715
725
735
745
755
765
775
785
795
805
815
825
835
845
855
865
875
885
885
YAp
Not
applicable.
Borehole bearing
converted to uncorrected azimuth, radius of curvature calculator program.
Corrects for magnetic
declination (Navajo Dam, add
12'
E in NE quadrant).
Engineering 40 scale used to eliminate reader bias.
*changes to TVD: Up -,
Down
+.
3~og
of desired
departures every
10 ft, collar
to 880 f
t using azimuth of 0.76O.
4~epth
at which desired
departures calculated.
5~orehole terminated at 495 ft, new
borehole sidetracked at 289
ft.
Borehole resurveyed
89 to 279
ft because of
defective survey hardware; used
original surveys 0 to 89 ft.
619
629
639
649
659
669
679
689
699
709
719
729
739
749
759
769
779
789
799
809
819
829
839
849
859
869
885
100.5
100.2
100.8
101.5
100.9
100.2
98.9
99.5
100.1
98.9
99.5
100.1
101.0
102.1
101.4
101.2
100.0
100.1
100.1
101.2
102.2
103.1
103.3
103.8
104.1
104.1
103.8
347.00
347.90
348.70
349.80
350.10
350.70
350.00
349.50
348.40
344.40
344.20
345.00
346.50
350.60
352.10
353.40
347.50
348.40
348.60
350.10
352.80
351.60
348.60
349.70
347.50
347.00
345.60
0.13
-009
005
.2 1
.33
.41
.40
.30
.16
-028
-064
-058
-038
.09
.57
.81
.42
.OO
-009
.23
.59
.71
.36
-19
.lo
-018
-035
-1.86
-1.80
-1.82
-1.93
-1.94
-1.83
-1.66
-1.60
-1.70
-1.65
-1.60
-1.70
-1.83
-2.00
-2.04
-1.96
-1.84
-1.74
-1.75
-1.85
-2.03
-2.19
-2.20
-2.34
-2.41
-3.41
-2.89
9.82
9.84
9.83
9.81
9.80
9.82
9.80
9.87
9.85
9.86
9.85
9.84
9.82
9.79
9.77
9.77
9.82
9.84
9.84
9.82
9.77
9.73
9.73
9.72
9.70
3.68
1.64
52,707.24
52,707.15
52,707.20
52,707.42
52,707.75
52,708.16
52,078.57
52,708.87
52,709.03
52,708.76
52,708.12
52,707.53
52,707.15
52,707.24
52,707.81
52,708.63
52,709.05
52,709.04
52,709.13
52,709.37
52,709.45
52,710.60
52,711.02
52,711.22
52,711.32
52,711.14
52,710.80
52,706.91
52,707.04
52,707.17
52,707.30
52,707.43
52,707.56
52,707.69
52,707.82
52,707.95
52,708.08
52,708.21
52,708.34
52,708.47
52,708.60
52,708.73
52,708.86
52,708.99
52,709.12
52,709.25
52,709.38
52,709.51
52,709.64
52,709.77
52,709.90
52,710.03
52,710.16
52,710.29
20,179.38
20,189.21
20,199.05
20,208.85
20,218.67
20,228.48
20,238.33
20,248.20
20,258.05
20,267.91
20,277.76
20,287.60
20,297.42
20,307.22
20,316.99
20,326.76
20,336.58
20,346.42
20,356.27
20,366.09
20,375.86
20,385.60
20,395.32
20,405.04
20,414.75
20,428.32
20,439.96
620
630
640
650
660
670
680
690
700
710
720
730
740
750
760
770
780
790
800
810
820
830
840
850
860
870
880
-5,955.33
-5,997.12
-5,998.95
-6,000.88
-6,002.82
-6,004.65
-6,006.31
-6,007.91
-6,009.61
-6,011.26
-6,012.86
-6,014.56
-6,016.39
-6,018.40
-6,020.43
-6,022.39
-6,024.23
-6,025.98
-6,027.73
-6,029.58
-6,031.61
-6,033.80
-6,036.08
-6,038.42
-6,040.83
-6,044.24
-6,047.14
