Overview of the Use of CO2 as Applied to
Enhanced Oil Recovery (EOR) Projects
 EGRC 6th Session
 Geneva, Switzerland  April 2015
What is CO2 Enhanced Oil Recovery (EOR)?
• Carbon dioxide mobilizes oil to improve recovery
o Mainly through miscible processes, but can be immiscible
• Viscosity of oil trapped in the reservoir is reduced providing ability
for more efficient displacement
• Injected CO2 produced with oil is captured & recycled
• Up to 50% of the injected CO2 is trapped in the reservoir
• Industry has produced, transported & injected CO2 without notable
incident for over 40 years
• Many similarities & experience applicable to Carbon Capture &
Storage (CCS)
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CO2 EOR Process
Water injection (blue) recovers
oil in large pores; leaving trapped
oil (red) in small pores
Waterflood
CO2 (yellow) dissolves and displaces
trapped oil; leaving only heavy ends
(brown) in the reservoir
CO2 flood
The process is normally finalized
by injecting chase water (blue)
after the CO2
Chase Waterflood
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CO2 EOR Process
CO2
Produced Gas
Produced
Vapor
Liquids
Recovery
CO2 Recycled from
Gas Plant
Pipeline CO2 from CO2 source
fields and natural gas
separation plants
Oil Sales
Produced Brine
Injection
Injection
well
Reservoir
Natural Gas & Natural Gas
Liquid (NGL) Sales
Production
well
Drive
Water
CO2
Water
CO2
Miscible
Zone
Oil
Bank
Additional
Oil
Recovery
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CO2 EOR Applicability
•Requires specific geological characteristics
oAdequate flood sweep efficiency (formation
heterogeneity, stratified or low vertical
permeability, few fractures)
oAdequate processing rate (CO2 velocity:
permeability and porosity)
oLow minimum miscibility pressure (low reservoir
temperature, low reservoir pressure)
•Requires CO2 source
•Requires sufficient oil target to be profitable
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Benefits of CO2 EOR




Significant long term cash generation  Four times the recovery from primary
operations
Shallow decline, long lived production
Proven technology
 Low Finding & Development (F&D) costs
No exploration risk
 Synergistic with carbon capture projects
Oil Production, MBOPD
Recovery of Oil in Place
1,000
60%
Waterflood
50%
Primary
100
CO2
40%
30%
10
Waterflood
30%
20%
10%
1
1938 1947 1957 1967 1977 1987 1997 2007 2017
CO2 15%
Primary
15%
Primary
6-12%
Conventional
Reservoirs
Unconventional
Reservoirs
0%
Recovery Percentages Represent Typical Recovery Efficiencies
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CO2 Flooding Injection Strategies
CONTINUOUS CO2
CO2
 Continuous CO2 Yields Fastest Oil
Response
WATER
 Water Alternating Gas (WAG)
Needed to Control Gas Production
ALTERNATING WATER AND GAS
 Tapered WAG Used to Maximize
Oil and Manage Gas
TAPERED INJECTION SCHEDULE
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Oil Production
0.14
0.12
0.1
0.08
ALTERNATING
0.06
0.04
0.02
0
0
10
20
Year
30
40
Forecasted Gas Prod (MMCFPD)
Per Typical 70 Acre-Pattern
Forecasted Recovery (Frac OOIP)
0.16
CO2 Production
3.5
3
2.5
2
ALTERNATING
1.5
1
0.5
0
0
10
20
30
40
Year
7
7
CO2 EOR in the United States
~125 mmcfpd
~375 mmcfpd
~1750 mmcfpd
>1100 mmcfpd
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Permian Basin Miscible CO2
EOR Production is Growing
Production - Thousand BOPD
225
200
175
150
125
100
75
50
25
0
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014
Source: Oil and Gas Journal Biannual EOR Surveys
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CO2 EOR Summary
•
Increases oil recovery 15-25%
•
The process is a closed loop system since CO2 produced with the oil is recovered
& recycled
o Net utilization 5-20 thousand cubic feet/barrel oil produced (mcf/bo),
depending on the geology and petrophysics
o Losses <1%
•
CO2 is treated as an expensive, scarce commodity
•
Proven technology: Industry has 35+ yrs of experience
•
Vast majority of projects are in the USA due to naturally occurring sources of CO2
• Non-USA opportunities are expanding, as examples:
o Natural
o Brazil (Lula)
o Anthropogenic
o Canada (Weyburne/Midale via US-based Dakota Gasification Plant)
o Saudi Arabia (Ghawar/Uthmaniyah Gas Plant)
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