Dynamics of subcritical CO/sub 2//brine floods for heavy-oil recovery

Journal Article · Mon Feb 01 04:00:00 EST 1988 · SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States)

OSTI ID:5287768

Rojas, G A; Ali, S M.F.

Immiscible CO/sub 2/ flooding is an important, field-proven heavy-oil recovery method, particularly suited for thin, marginal, or otherwise poor heavy-oil reservoirs, where thermal recovery processes are likely to be uneconomical. This paper describes the dynamics of this recovery technique on the basis of experiments conducted in a scaled model. The experiments represent a medium-heavy oil (1032 mPa . s at 23/sup 0/C (1,032 cp at 73/sup 0/F)) occurring in a shallow, thin sand. CO/sub 2/ was injected together with brine at subcritical conditions (5.5 MPa and 21 to 23/sup 0/C (800 psi and 70 to 73/sup 0/F)). The CO/sub 2/ and brine superficial velocities were varied from 0.18 to 2.9 m/d (0.6 to 9.5 ft/D). This broad range of velocities permitted the study of the effect of the viscous, diffusive, and gravitational forces on the CO/sub 2/ slug (20% HCPV) process for heavy-oil recovery. It was found that viscous forces completely dominant CO/sub 2/ injection. Also, the mass transfer between CO/sub 2/ and oil had a stabilizing effect on the brine injection. Although the molecular diffusion of CO/sub 2/ in oil was high, it was not high enough to mobilize appreciable amounts of oil from uninvaded zones. The scaled experiment results showed that oil recoveries at CO/sub 2/ and brine breakthroughs were rate-dependent. While recovery at CO/sub 2/ breakthrough decreased with increasing rate, recovery at brine breakthrough increased. Reduction of interfacial tension (IFT) between brine and oil, leading to the formation of brine-in-oil emulsions, was found to be an additional effective mechanism of heavy-oil recovery by CO/sub 2//brine injection.

• Research Organization: Univ. of Oriente (VE)
• OSTI ID: 5287768
• Journal Information: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States), Journal Name: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States) Vol. 3:1; ISSN SREEE
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
BRINES
CARBON DIOXIDE INJECTION
CHEMICAL COMPOSITION
DISPLACEMENT FLUIDS
EMULSIFICATION
ENERGY SOURCES
ENHANCED RECOVERY
FLOW RATE
FLUID INJECTION
FLUIDS
FOSSIL FUELS
FUELS
MISCIBLE-PHASE DISPLACEMENT
OIL WELLS
PETROLEUM
RECOVERY
ROCKS
SANDSTONES
SCALE MODELS
SEDIMENTARY ROCKS
STIMULATION
STRUCTURAL MODELS
SURFACE PROPERTIES
SURFACE TENSION
VISCOSITY
WATERFLOODING
WELL STIMULATION
WELLS