STRATIGRAPHIC ARCHITECTURE AND RESERVOIR CHARACTERIZATION OF THE SILURIAN RACINE FORMATION, FORSYTH

FIELD, CENTRAL ILLINOIS

Yaghoob Lasemi

Illinois State Geological Survey, University

of Illinois at Urbana-Champaign

Geological Society of America Annual Meeting, October 2017

Acknowledgements

This work is partially funded by the U.S. Department of

Energy – National Energy Technology Laboratory through

CarbonSAFE Illinois–Macon County Grant No. DE-

FE0029381 (Steven G. Whittaker PI). Original draft of

contour maps and cross-sections were prepared using IHS

PETRA through their University Grant Program.

1. Geologic setting

2. Field discovery and development

3. Stratigraphy and reservoir characterization

4. Reservoir development and petroleum entrapment

5. Potential for future development

Presentation Outline

Illin

ois

Ba

sin

Du

rin

g S

ilu

ria

n T

ime

(M

od

ifie

d

fro

m L

as

em

i e

t a

l., 2

01

0;

La

se

mi, 2

01

4)

Illin

ois

Ba

sin

an

d t

he

Su

rro

un

din

g A

rch

es

a

nd

Do

me

s (

Ko

lata

an

d N

els

on

, 2

01

0)

Mt.

Au

bu

rn T

ren

d O

il F

ield

s i

n t

he

So

uth

ern

Fla

nk o

f th

e S

an

gam

on

Arc

h

Reen

try i

n S

ch

warz

# 1

, an

Old

Dry

Ho

le,

Led

to

Dis

co

very

in

196

3

An

nu

al

Oil P

rod

uc

tio

n,

19

63

-201

3;

Majo

r D

eve

lop

men

t in

Ea

rly 8

0s

Stratigraphy and Correlation

Str

ati

gra

ph

ic N

om

en

cla

ture

of

the

Silu

ria

n S

ys

tem

an

d G

lob

al S

ea

Le

ve

l C

ha

ng

es

(R

ac

ine

Su

bd

ivis

ion

fr

om

La

se

mi, 2

00

9;

La

se

mi e

t a

l., 2

01

0)

Ge

ne

ral

Str

ati

gra

ph

ic C

olu

mn

,

So

uth

eas

t M

arg

in o

f th

e S

an

gam

on

Arc

h

Stratigraphic Reference Section (Schwarze-Pense Com. No. 2, API #121152144400)

Reservoir Occurrence

and Variability

So

uth

west-

No

rth

east

Str

ati

gra

ph

ic

Co

rrela

tio

n,

Mt.

Au

bu

rn T

ren

d

No

rth

west-

So

uth

east

Str

ati

gra

ph

ic

Co

rrela

tio

n,

Fo

rsyth

Fie

ld

So

uth

we

st-

No

rth

eas

t S

trati

gra

ph

ic

Co

rrela

tio

n,

Fo

rsyth

Fie

ld

So

uth

-to

-No

rth

Str

ati

gra

ph

ic C

orr

ela

tio

n,

Fo

rsyth

Fie

ld

Res

erv

oir

Co

mp

art

men

ts D

evelo

ped

in t

he

Hig

hsta

nd

Packag

e o

f th

e U

pp

er

Racin

e S

eq

uen

ce

Co

re S

am

ple

s f

rom

Po

do

lsky

Oil

Co

.

Mc

Mil

len

B-4

, M

t. A

ub

urn

Co

nso

lid

ate

d F

ield

, C

hri

sti

an

Co

un

ty

Depositional and Diagenetic Model for Reservoir Development

in the Silurian Deposits of the Study Area (Photomicrograph Scale Bar: 0.5 mm)

Thickness Map of the Main Reservoir Reservoir Top Structure Contour Map

Potential for Improving Recovery

1. Calculated OOIP: Over

10,000,000 barrels.

2. Production per well: Less

than 10,000 bbl./solution gas

and gravity drive.

3. DST: Low SIP and negligible

fluid recovery.

4. Initial oil production: Nearly

40 bbl. Average.

Poor Reservoir

Performance

1. Infill drilling.

2. Development of undrilled areas.

3. Larger volume hydraulic fracturing.

4. Horizontal drilling.

5. Enhanced recovery through

waterflooding or CO2 EOR.

Suggestions for

Increased Production

The Silurian reservoir interval at Forsyth consists of dolomite bodies

that occur in the upper part of small scale cycles, which suggest sea

level fluctuation as the major control for their development.

Low recorded shut-in pressure and negligible fluid recovery in DST,

insignificant initial oil production, and below average cumulative primary

production per well suggest poor permeability.

Infill drilling and development of the undrilled areas, large volume

hydraulic fracturing, and horizontal drilling could lead to significant

increased production from the field.

The field has produced less than 10% of its OOIP and has never been

flooded. It has a great potential for significant increased recovery

through waterflooding and CO2-EOR.

Conclusions

Thank You