1

SACROC CO2 Flood

Project Challenges: Past,

Present, and Future

Presented at the 19th Annual CO2 Flooding Conference

December 11-13, 2013

Midland, Texas

1

SACROC is in the

Kelly-Snyder Field,

largest of a chain of

Canyon Reef Fields

making up the

Pennsylvanian

Aged Horseshoe

Atoll

2

4

SACROC Unit Information

• Field discovery 11/1948

• Productive area: 49,980 acres

• Formation: Canyon Reef

• OOIP: 2,800 MMSTBO

• Oil column thickness: up to 900 ft in

Platform

• Average depth: 6800’

• Discovery pressure: 3122 psi

• Oil gravity: 42 API

• HC GOR:

– Original: 1000 Scf/Stbo

– CO2 Flood: 2600 Scf/Stbo

• Rich gas, 230 Bbls NGL/Mmscf

HC gas

• Total CO2 Flood Gas GOR:

28,000 Scf/Stbo

• 11/2013 Production & Injection: – 31,900 BOPD

– 18,900 BPD NGL

– 1,040 MMSCFID CO2 (90% Recycled)

3

1,000

10,000

100,000

1,000,000

10,000,000

1/1/1945 1/1/1955 1/1/1965 1/1/1975 1/1/1985 1/1/1995 1/1/2005 1/1/2015

Dai

ly R

ate

s (B

OP

D, B

WP

D, B

WIP

D, C

O2

Pro

du

ctio

n &

Inje

ctio

n M

SCFD

)

SACROC Unit Performance HistoryBOPD

BWPD

CO2 Recycle (MSCFD)

BWIPD

CO2 Injection (MCFID)

4

11/1948: Field discovery

9/1954: Center Line Water Injection begins

Late 1971: Pattern waterflood begins

1/1972: CO2 injection begins

3/1974: Peak oil rate (215,000 Bopd)

1975: 20-acre infill drilling, 40-acre 5-spot development

Cumulatives:

Oil Prod: 1.36 Bstbo

CO2 Inj: 4.92 Tcf

CO2 Recovery: 2.99 Tcf

P1AP1B

P3 North

P3 SOUTH

P4

SACROC 1974 Center Line CO2 Injection Test Patterns

SACROC Cumulative CO2

Injection to 1/1/1975

•Two 40-acre 5-spots were

drilled in in a watered out

area in the Center Line

Area

•Definitive 200 BOPD oil

response occurred

•CO2 injected for 10

months, 16% HCPV CO2,

1.5% OOIP EOR

5

1

10

100

1000

10000

100000

1/1/1973 1/1/1974 1/1/1975 1/1/1976 1/1/1977

BO

PD

, BW

PD

, HC

MSC

FD, C

O2p

MSC

FD, B

WIP

D,

CO

2i M

SCFI

D

SACROC Unit Center Line CO2 Test AreaBOPDBWPDHC MSCFDCO2 MSCFDBWIPDCO2 MSCFID

100

1000

10000

100000

1/1/1970 1/1/1975 1/2/1980 1/1/1985

Da

ily R

ate

s (B

PD

, MSC

FD)

BOPD

BWPD

CO2 MSCFD

BWIPD

CO2 MSCFID

SACROC 4-Pattern Area CO2 Flood Pilot

Cumulative CO2 Injection

Bubble Map through January,

1996

• Pilot conducted in south part of Unit ahead of the CO2 injection expansion

into the south of the Unit

• Pilot made up of four ~160-acre inverted 9-spot patterns

• 2000 BOPD+ of definitive oil response

• EOR was 10% of OOIP after 30% HCPV CO2 injection

• However, oil influx from outside project area complicates analysis; IWR<1.0

Water

injection

from 1973

to 1981

CO2-WAG

injection

from 1981

to 1986

6

Norflood

SW Bank

Center Line

SACROC Early 1997 CO2 Injection Focusing on Center Line,

Norflood, & SW Bank Redevelopment Projects

• Pennzenergy suspected that SACROC

hadn’t been effectively CO2 flooded

– Other West Texas projects beginning CO2

injection in the 1980’s and 1990’s had

exhibited significant CO2 Flood EOR

Wedges

– SACROC’s CO2 injection had been

conducted using high WAG ratios,

sometimes below MMP

• Three focused CO2 flood test areas were

initiated:

– Norflood

• Focused on low permeability Middle

Canyon

– Southwest Bank

• Focused CO2 injection in lower

permeability reservoir

– Center Line

• Focused 40-acre 5-spot pattern

development

7

Initial KM CO2 Flood Redevelopment

• KM Purchased SACROC in

2000

• Expanded upon Pennzenergy’s

successful Center Line CO2

flood project

• KM expanded its CO2 pipeline

infrastructure in 2003 by

installing the Centerline Pipeline

to deliver another 300 MMSCFD

to the SACROC area and

beyond

8

McElmo Dome

St. John’s

Yates

Sacroc

Katz

CO2 Pipelines

Doe Canyon

Year Project

1996: Center Line 1 & 2 Expansions (CL1 & CL2)

2001: Center Line 3 (CL3)

2002: Center Line 4 (CL4)

2002: Center Line 5 (CL5)

2003: Bull’s Eye (BE)

2004: Center Ring 1 (CR1)

2005: Center Ring 2 (CR2)

2007: Southwest Center Line 1 & 2 (SWCL1 & 2)

2008: Southwest Center Line 3 (SWCL3)

2008: Gilligan’s Island (GI)

2008: South Platform (SP)

Platform development was deferred until all

of the Central Plain areas were completed.

CL

1

CL3

CR1

CR2 GI

SWCL

1 & 2

BE

SP

SACROC CO2 Flood Redevelopment Project Areas 1996-2008

CR2

CR2

9

1996-2008 CO2 Flood Project Area Contribution to

Total Unit Production

10

0

5000

10000

15000

20000

25000

30000

35000

40000

1/1/1995 1/1/2000 1/1/2005 1/1/2010

Oil

Rat

e (

BO

PD

)

Gilligan's Island

South Platform

Southwest Center Line

CR 2

CR 1

Bullseye

CL 5

CL 4

CL 3

CL 1 & 2

SACROC Unit Total

Platform CO2 Flood Development

• SACROC Platform Area has

the thickest pay in all of

SACROC

– OOIP: 951 MMSTBO

– Area: 5700 acres, 145 patterns

• Complex, Highly

Heterogeneous Reservoir

– Some Dual, Triple injection well

completions used to better

distribute CO2 injection

11

37-11 Core

Location

Perforating for Conformance - Intervals

Intervals

Cisco

Green Zone

MCN3

Lower Middle Canyon

Descriptions

Moderate matrix permeability, unconnected fractures result in fast processing rates in some areas, porosity lenses not well connected.

Thick and continuous with good matrix permeability. Characterized by highly permeable features that short circuit sweep through matrix.

High permeability matrix, good continuity, excellent sweep.

Layered and continuous. Low porosity and matrix permeability. Few fractures or high permeability features.

SACROC Platform Pay Zone Intervals

12

SACROCwestside

SACROCsouth and eastside

SACROCupper Green Zone

Platform Area Green Zone

Navassa Island Modern Day Green Zone Analog Karsted Core Sample

13

P1A & P1B 2009 Initial Platform CO2 Flood Project Areas

• Expanding CO2 Flood into

the Platform meant

confronting severe CO2

channeling issues

– Several cases of CO2

breaking through within

hours of starting CO2

injection

• IDEA (Infill Development

Experimental Area)

– 10-acre infill drilling & conversion

project was implemented to create

20-acre 5-spot patterns

– Objective was to increase recovery

by connecting up discontinuous pay

and allow faster processing of lower

permeability layers

• Unfortunately the infill

drilling also connected up

the high permeability

layers/channels

14

10-acre IDEA Producers

IDEA Conversions to

Injection

P1A P1B

CO2 Channeling Issues

• Early CO2 channeling issues resulted in several patterns having to be shut-in

– Cross-linked polyacrylate gel treatments successfully controlled many of the

problems (except in the most extreme cases)

– The long pump times required for placing the polymer treatments resulted in

substantial production downtime

15

Injecting Polymer

Polymer Finished

Shut In after BT

RTP

RTI CO2

Confirmed Channel

Suspected Channel

IDEA Area Map Showing Channels Indicated by Polymer Testing

P2 Project Design Changes

• Pre-Injection Polymer

Treatments were pumped

– Pumping polymer before

beginning CO2 injection

avoided significant production

downtime

• Where economically justified,

three injection well completions

were implemented to better

distribute CO2 injection

• Horizontal producer was drilled

on east side of project

– Replaced drilling 5 vertical

wells

16

37-11

SACROC Pattern 37-11 Triplet

Injection Completion

CO2 Water CO2 Water CO2 Water

Cisco

Green

Zone

Middle Canyon

Completion

OOIP

(MSTBO)

2013

Average

Injection

(RBPD)

Processing

Rate

(%HCPV/Yr)

Cisco 3255 5452 41%

GZ/UMCN 5845 6242 26%

LMCN 3121 1055 8%

Total 12221 12750 25%

17

SACROC Pattern 37-11

18

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0

100

200

300

400

500

600

700

800

900

Jan

-12

Jul-1

2

De

c-12

Jul-1

3

De

c-13

CO

2 P

rod

uct

ion

(MS

CFD

), W

ate

r P

rod

uct

ion

(BW

PD

)

Oil

Ra

te (

BO

PD

)

Actual BOPD

Actual BWPD

Actual CO2p MCFD

0

4000

8000

12000

16000

20000

24000

28000

32000

36000

Jan

-12

Jul-1

2

De

c-12

Jul-1

3

De

c-13

CO

2 In

j R

ate

(M

SC

FD)

Total Pattern CO2 Inj Rate

Lower Middle Canyon

Green Zone

Cisco

SACROC

Platform

Oil Rate

Tests

12/2013

19

Horizontal Producers

20

Horizontal

Producing

Well

• Drilling a horizontal producer replaced drilling

5 vertical wells

• Well was completed using 18 cross-

linked gelled acid stages

• Being able to drill horizontal producers will

reduce the development cost of expanding

the CO2 flood project into the thinner patterns

along the edge of the field

1

10

100

1,000

10,000

100,000

Dai

ly R

ate

s

SACROC Horizontal Producer 30-22H

Oil (BBLS)

Water (BBLS)

Gas (MCF)

Sum of Offset CO2 Injection (MSCF)

Lower MCN Horizontal Injection Completions

• Concerns over Lower MCN

vertical well drilling costs,

reservoir processing rates led to

approving 6 horizontal injection

wells in the P3 South and P3

North CO2 Flood Project Areas

– Vertical well Lower MCN

processing rates estimated to

be <10% HCPV/yr

– Multi-stage acid fractured

Lower MCN processing rate

expected to be >25% HCPV/yr

• All 3 of the P3 South wells have

be successfully drilled and

completed

– 11-16H began CO2 injection on

11/27/13; currently injecting

25,000 MSCFD (30% HCPV/yr)

21

11-16H

1996-2013 CO2 Flood Project Area Contribution to

Total Unit Production

22

Future SACROC CO2 Flood Development

4-Component Strategy:

– Exploit Transition Zone

– By-Passed Redevelopment

– Edge Pattern Development

– Reassessment of Infill Development Potential

23

SACROC South Shore Transition Zone Test

Patterns 296-1 and 296-2

24

SACROC South Shore Transition Zone Test Patterns 296-1 and 296-2

10

100

1000

10000

100000

7/1/2011 12/30/2011 6/30/2012 12/29/2012 6/30/2013

Rat

e (B

PD

, M

SCFD

)

SACROC Unit Pattern PATS 296-1 & 296-2

Actual MCFID

Actual BWPD

Actual CO2p MCFD

Actual BOPD

Bypassed MCN Pay Horizontal Injector 155-18H

25

P1A

P1B

PAT 100-1

PAT 101-1

PAT 102-2

PAT 102-3

PAT 103-1

PAT 104-1

PAT 105-2

PAT 106-1

PAT 106-3

PAT 107-1

PAT 107A-1

PAT 109-1A

PAT 109-4

PAT 109-5A

PAT 110-2

PAT 110-3

PAT 111-1

PAT 111-4

PAT 112-1

PAT 112-3

PAT 113-3A

PAT 114-1

PAT 115-1GAP

PAT 115-2

PAT 115-4

PAT 115-5GAP

PAT 116-1

PAT 116-3 PAT 116-7GAP

PAT 117-1

PAT 117-2PAT 117-3

PAT 117-4

PAT 118-1

PAT 118-10

PAT 118-11

PAT 118-12

PAT 118-2

PAT 118-28PAT 118-3

PAT 118-4AGAP

PAT 118-5PAT 118-6

PAT 118-7

PAT 118-8

PAT 119-1

PAT 119-2PAT 120-1

PAT 120-2

PAT 121-1PAT 121-2

PAT 121-3

PAT 121-4

PAT 121-5

PAT 122-1PAT 122-2

PAT 122-3

PAT 123-1PAT 123-2

PAT 123-4PAT 123-6

PAT 124-11

PAT 124-12

PAT 124-13PAT 124-15

PAT 124-7PAT 125-5

PAT 127-1

PAT 127-5

PAT 128-X

PAT 128-Y

PAT 129-2PAT 129-4A

PAT 132-1PAT 132-2

PAT 133-1

PAT 136-3

PAT 136-7

PAT 136-X

PAT 136-Y

PAT 136-Z

PAT 137-X

PAT 138-1

PAT 138-13

PAT 138-2

PAT 138-3

PAT 138-5

PAT 138-6A

PAT 138-7A

PAT 138-8

PAT 139-2APAT 139-6

PAT 140-5PAT 140-6

PAT 141-1

PAT 141-2PAT 141-3

PAT 141-4

PAT 142-1PAT 142-3

PAT 142-8PAT 142-9

PAT 143-1

PAT 143-2

PAT 143-3GAP

PAT 143-4

PAT 144-1

PAT 144-2

PAT 145-1A

PAT 145-4

PAT 146-1

PAT 146-2

PAT 146-3

PAT 146-4

PAT 147-1

PAT 147-2

PAT 147-3

PAT 147-4

PAT 147-5PAT 147-6

PAT 147-7

PAT 147-8

PAT 148-1

PAT 148-11

PAT 149-1

PAT 150-1PAT 150-4GAP

PAT 150-5

PAT 151-1PAT 152-3A

PAT 152-5

PAT 153-1

PAT 153-12

PAT 153-2

PAT 154-2

PAT 155-2

PAT 155-6

PAT 155-8 PAT 155-9

PAT 156-2PAT 156-3

PAT 156-4GAP

PAT 156-6

PAT 157-1

PAT 157-6

PAT 158-5

PAT 159-1

PAT 159-3

PAT 159-5

PAT 160-4

PAT 160-5

PAT 163-2

PAT 163-3

PAT 164-1

PAT 165-2PAT 166-1

PAT 166-10A

PAT 166-11

PAT 166-13

PAT 166-14

PAT 166-21

PAT 166-2GAP

PAT 166-3

PAT 166-6

PAT 166-8

PAT 167-6GAP

PAT 167-8

PAT 167-9PAT 168-5

PAT 169-1 PAT 169-3

PAT 169-5

PAT 170-1

PAT 170-2

PAT 171-1

PAT 171-2

PAT 171-4

PAT 172-1

PAT 172-6GAP

PAT 172-7

PAT 173-10

PAT 173-11

PAT 173-13

PAT 173-2

PAT 173-3

PAT 173-9GAP

PAT 174-1

PAT 174-2PAT 174-3

PAT 174-4

PAT 175-2

PAT 176-5

PAT 176-8GAP

PAT 177-3PAT 177-4A

PAT 177-5

PAT 177-6

PAT 178-1PAT 178-2

PAT 178-3GAP

PAT 178-4

PAT 179-1PAT 179-2

PAT 179-5GAP

PAT 179-6

PAT 180-7

PAT 180-8

PAT 181-3

PAT 184-1

PAT 187-1

PAT 188-2

PAT 188-5

PAT 188-6

PAT 189-1

PAT 190-2

PAT 198-1

PAT 198-7

PAT 199-1

PAT 199-7

PAT 200-1

PAT 200-7

PAT 202-1

PAT 203-6

PAT 203-7

PAT 203-8

PAT 203-9

PAT 204-2 PAT 204-7

PAT 205-2

PAT 206-1

PAT 206-5A

PAT 206-6

PAT 206A-7

PAT 207-5

PAT 208-2

PAT 208-5

PAT 210-5

PAT 210-6

PAT 210-8

PAT 211-2

PAT 212-2

PAT 212-4PAT 212-5

PAT 213-4

PAT 213-5PAT 214-3

PAT 215-2

PAT 215-5

PAT 215-6PAT 215-7

PAT 216-5PAT 216-6

PAT 217-1GAP

PAT 217-7

PAT 217-8PAT 217-9

PAT 220-5

PAT 221-1

PAT 221-2PAT 221-3

PAT 221-4

PAT 223-1GAP

PAT 223-2PAT 224-1

PAT 224-2GAP

PAT 225-10

PAT 225-11PAT 225-3A

PAT 225-8

PAT 227-5

PAT 228-5

PAT 228-6

PAT 228-7

PAT 229-1

PAT 229-2AGAP

PAT 230-4

PAT 232-2

PAT 233-2

PAT 234-1

PAT 256-2

PAT 257-4

PAT 258-1PAT 259-1

PAT 259-2A

PAT 260-5

PAT 261-1A

PAT 261-2

PAT 261-6

PAT 261-7A

PAT 262-7

PAT 262A-1A

PAT 262A-2A

PAT 263-1A

PAT 263-9

PAT 265-2A

PAT 266-1A

PAT 267-3

PAT 268-2A

PAT 268-4

PAT 269-1A

PAT 269-3

PAT 270-1

PAT 270-3

PAT 271-1A

PAT 271-4

PAT 272-1

PAT 272-4

PAT 273-1A

PAT 273-4

PAT 274-1

PAT 274-2

PAT 293-2

PAT 299-1A

PAT 299-4APAT 303-4

PAT 44-1

PAT 44-4

PAT 45-1PAT 45A-1

PAT 46-13PAT 46-14

PAT 46-16

PAT 46-6

PAT 50-2A

PAT 51-1A

PAT 51-2PAT 51-4A

PAT 51-8

PAT 52-2APAT 53-2A

PAT 54-1APAT 54-2

PAT 54-3PAT 54-4

PAT 56-10APAT 56-28PAT 56-3APAT 56-5APAT 56-7APAT 56-9A

PAT 57-1PAT 57-2A

PAT 57-3PAT 57-4 PAT 60-1PAT 60-2

PAT 60-3APAT 60-4A

PAT 61-2

PAT 61-5

PAT 61-9

PAT 64-4

PAT 65-1PAT 65-10

PAT 65-2APAT 65-3

PAT 65-5

PAT 65-6

PAT 65-9

PAT 67-1A

PAT 67-2PAT 67-3A

PAT 67-4A

PAT 67-5A

PAT 67-6

PAT 67-9

PAT 68-7

PAT 69-1APAT 69-2

PAT 69-3APAT 69-4A

PAT 70-1PAT 70-3A

PAT 70-8

PAT 71-1

PAT 71-3PAT 71-4

PAT 71-8

PAT 72-1

PAT 72-2

PAT 72-3

PAT 72-4

PAT 72A-7

PAT 73-1PAT 73-2

PAT 73-3 PAT 73-4

PAT 74-10

PAT 74-11

PAT 74-2

PAT 74-9

PAT 75-16PAT 75-2

PAT 75-3PAT 75-4

PAT 75-5

PAT 75-6

PAT 75-7

PAT 75-8

PAT 76-1

PAT 77-1 PAT 77-2

PAT 77-3

PAT 77-4

PAT 77-8

PAT 79-5

PAT 79-6PAT 79-7

PAT 81-1PAT 81-2

PAT 81A-1PAT 82-2

PAT 84-3PAT 85-1

PAT 85-2

PAT 85-3 PAT 85-4

PAT 85-5

PAT 85-6

PAT 85-7

PAT 86-11

PAT 86-15A

PAT 86-2

PAT 86-3A

PAT 86-4

PAT 86-5A

PAT 86-9APAT 87-2

PAT 87-4PAT 88-3

PAT 89-1A

PAT 89-2

PAT 90-3

PAT 90-4A

PAT 91-11

PAT 91-12PAT 91-13

PAT 91-14 PAT 91-15

PAT 91-3GAP

PAT 91-4

PAT 91-5

PAT 91-9GAP

PAT 92-10

PAT 92-12

PAT 92-1GAP

PAT 92-9

PAT 93-3

PAT 94-2

PAT 94-3

PAT 94-5

PAT 96-1

PAT 98-1

PAT 99-4

PAT 99B-2A

26

Center Ring 1 & 2 Bypassed Pay

12-Horizontal Well Redevelopment Area

Potential CO2 Flood Expansion Patterns

27

• Although pay quality is less favorable, significant

OOIP (>500 MMSTBO) exists outside the active

or currently proposed project areas

• Challenges to developing these patterns include

– Few if any available well bores

– Insufficient pay volume to economically justify

traditional pattern development

• Potential solutions being evaluated include:

– Multi-stage fracture stimulated horizontal

producers and injectors

– Including Transition Zone reservoir volumes in

recovery forecasts

– Identifying areas that water flooded well,

indicating they will respond well to

CO2 injection

IDEA versus Offset Project Recoveries

28

0.000 0.000

0.000

0.012

0.019

0.009

0.074

0.0380.094

0.053

0.039

0.025

0.025

0.0730.042

0.0320.041 0.064

0.0370.037

0.024 0.0090.004

0.050 0.0350.043

0.098 0.0780.043

0.010

0.0020.007

0.000

0.001

0.0040.002

0.000

0.000

0.0020.0090.0340.029

0.0230.025

0.0090.016

0.005

0.0310.0620.027

0.0340.013

0.0120.0200.018

0.0180.013

0.0180.010

0.194 0.153 0.030

0.0160.0100.012

0.071 0.077

0.0390.061 0.0320.0090.014

0.033 0.033 0.040 0.0570.019

0.030

0.057 0.0350.0200.0050.052 0.056

0.0290.023

0.0470.057

0.017

0.0350.055

0.0690.087

0.035

0.060

0.105

0.073

0.099

0.069

0.081

0.107

0.104

0.096

0.058

0.067

0.0650.032

0.047

0.040

0.040

0.0240.013

0.065 0.122 0.051

0.0500.037 0.005

P1A

P1B

P3 North

P3 SOUTH

P4

PAT 14-4

PAT 16-2

PAT 16-4 PAT 16-6

PAT 16-7

PAT 16-8

PAT 18-2M

PAT 18-4PAT 18-4APAT 18-4M

PAT 18-6APAT 18-6M

PAT 18-7A

PAT 18-7M

PAT 18-8PAT 20-4PAT 20-5

PAT 20-6PAT 20-8

PAT 21-4PAT 21-5

PAT 22-5

PAT 22-6

PAT 23-1

PAT 23-2

PAT 24-1PAT 24-3

PAT 24-4PAT 24-8

PAT 25-1

PAT 25-2APAT 25-3

PAT 25-4

PAT 26-1APAT 26-2A

PAT 26-3ALPAT 26-3AS

PAT 26-4A

PAT 26-5

PAT 26-6

PAT 26-7APAT 26-8

PAT 27-1APAT 27-2A PAT 27-3APAT 27-4

PAT 27-5APAT 27-6A

PAT 27-7A PAT 27-8APAT 27-8B

PAT 28-1A PAT 28-2APAT 28-3A

PAT 28-4 PAT 28-5APAT 28-6A

PAT 28-7APAT 28-7B

PAT 28-8APAT 28-8B

PAT 29-1

PAT 29-2

PAT 29-3 PAT 29-4

PAT 29-5 PAT 29-6

PAT 29-7

PAT 29-8

PAT 30-1

PAT 30-11A

PAT 30-12

PAT 30-13PAT 30-18

PAT 30-2APAT 30-2B

PAT 30-6PAT 30-8

PAT 31-13

PAT 32-14

PAT 32-16

PAT 32-17

PAT 32-24ALPAT 32-24ASPAT 32-3APAT 32-3B

PAT 32-4APAT 32-4B

PAT 32-5ALPAT 32-5AS

PAT 32-9A

PAT 33-10

PAT 33-1ALPAT 33-1ASPAT 33-1B

PAT 33-2PAT 33-2A

PAT 33-3APAT 33-3BPAT 33-4

PAT 33-5APAT 33-5B

PAT 33-7APAT 33-7B

PAT 33-9

PAT 34-5 PAT 34-6A PAT 34-7A

PAT 34-8

PAT 34-8APAT 34-8B

PAT 35-1 PAT 35-2A

PAT 35-3PAT 35-3A PAT 35-4APAT 35-4BLPAT 35-4BS

PAT 36-A1PAT 36-B2A PAT 36-C3A PAT 36-D4PAT 36-D4A

PAT 36-D4B

PAT 37-1PAT 37-11PAT 37-11APAT 37-11BPAT 37-2A PAT 37-3A

PAT 38-1APAT 38-2

PAT 38-3APAT 38-4

PAT 39-2A

PAT 39-3APAT 39-4

PAT 39-9PAT 40-1A

PAT 40-2

PAT 40-3A

PAT 40-4A

PAT 40-5

PAT 40-6

PAT 40-7

PAT 40-8

PAT 41-1

PAT 41-2

PAT 41-4

PAT 42-1

PAT 42-2

PAT 42-3

PAT 43-1

PAT 48-3

PAT 49-1

PAT 49-2A

PAT 49-3A

PAT 49-4A

PAT 49-5A

PAT 49-6A

PAT 49-7

PAT 49-8 PAT 55-1A

PAT 55-2A

PAT 55-3ALPAT 55-3AS

PAT 55-4A

PAT 58-1A

PAT 58-2A

PAT 59-1PAT 59-1A

PAT 59-2A PAT 59-3APAT 62-15

PAT 62-1APAT 62-1B PAT 62-3APAT 62-8

IDEA Pattern recoveries

to date are around 3%

higher than in offset

areas

Although initially plagued

by CO2 breakthrough

problems, the combination

of 10-acre infill drilling

polymer gel and

specialized cement

squeeze treatments may

have resulted in high

efficiency patterns Some improved recovery due to

targeting geologically isolated

“Green Zone” Pinchouts

Additional infill wells have been

recommended

Summary

• CO2 flooding has presented SACROC’s operators with engineering

challenges since 1972

• Focused CO2 flood development projects, injecting large pore volumes

of CO2 of 80-100% of the HCPV, have resulted in significant

incremental EOR

• Mitigating heterogeneity issues through the innovative application of

polymer, cementing, and horizontal well technologies has been critical

to CO2 flood performance success

• Continued CO2 flood development of the lower permeability bypassed

pay and reservoir around the edges, along with focused

vertical/horizontal infill drilling applications within existing flood areas,

will challenge SACROC engineers & geoscientists for many years to

come

Big fields keep getting bigger! 29