CO2 Enhanced Oil Recovery and Storage in Reservoirs
CHE384-Energy Technology and Policy
Xi Chen
Nov. 19th, 2007
EOR-Background
Primary recovery Natural pressure, 10% OOIP
Secondary recovery Injection of water or gas, 20-40%
OOIP Tertiary or enhanced oil recovery
Aiming at recovery of 30%-60% OOIP
Categories of EOR
Thermal recovery Steam flooding, ~50% of EOR
production Chemical injection
Polymer/water flooding, <1% Gas injection ~50%
immiscible flooding: CH4, N2 miscible flooding : CO2Process
Ult. Recovery% OOIP
Utilization
Miscible 10-15 10 MCF/bbl
Immiscible 5-10 10 MCF/bbl
Lecture notes from
Dr. Larry W. Lake
EOR by CO2 flooding
Advantages of CO2 flooding Dense fluid over much of the range of
pressure and temperature in reservoirs Low MMP (minimum miscibility
pressure) and high miscibility with oil Low mutual solubility with water Low cost and abundance
Naturally occuring source Environmental benefit if industrial CO2
is used and stored in reservoirs Capture and sequestration of CO2 from
combustion of fossil fuel
Source: Oil & Gas Journal
206,000 barrels per day in 2004 = 4% of the Nation’s total.
Screening criteria for application of CO2 miscible flood
Gozalpour, “CO2 EOR and Storage in Oil Reservoirs”, 2005,Oil & Gas Science and Technology – Rev. IFP, Vol. 60 (2005), No. 3, pp. 537-546
Optimum reservoir parameters and weighting factorsfor ranking oil reservoirs suitable for CO2 EOR
Rivas, O. et al. (1992) Ranking Reservoirs for Carbon DioxideFlooding Processes.
Technical challenge Poor sweep efficiency
Gravity override Mobility contrast Reservoir heterogeneity
CO2 related problem Corrosion on facilities Solid deposition in reservoir formation
Well spacing Greater spacing causes sweep efficiency
reduction
CO2 mobility control
Foam mixed surfactants as foaming agent
Thickening agent Fluorinated compound or polymer
(good solubility in CO2) Chemical gels
In-situ gelation of polymer to lower permeability
Most favorable site for storage Dense webs of seismic and well for
long-term trap Surface and subsurface infrastructure
readily converted for CO2 distribution and injection
Less costly
CO2 Storage in Reservoirs
CO2 Storage in Reservoirs
CO2 capacity of a reservoir: Theoretically, equal to the volume
previously occupied by the produced oil and water
Other factor: Water invasion, gravity segregation, reservoir heterogeneity and CO2 dissolution
Reservoir type, depth, size and safety of CO2 storage
Economics Cost of CO2 from different sources:
Naturally occuring CO2: $14/t Pure anthropogenic CO2 from chemical plant: $18/t Capture and processing of CO2 from coal fired plant: $18-
54/t
CO2 utilization efficiency: 4~8 Mscf/bbl (0.2~0.5t/bbl)
Transportation cost: $0.5~1.2/Mscf Operation cost: $2-3/bbl Economical even at a oil price of $40/bbl. CO2 storage credit ($2.5/Mscf) makes it more
economical for producers.
Lako, P. (2002) Options for CO2 Sequestration and EnhancedFuel Supply.
Summary Combination of CO2 EOR and storage in
reservoirs provides a bridge between reducing greenhouse gases from industrial waste streams and the beneficial use of CO2 injection for increasing oil and gas recovery.