Minimizing miscibility pressure aids EOR efforts

Journal Article · Tue Nov 01 04:00:00 EST 1983 · Pet. Eng. Int.; (United States)

OSTI ID:5154666

Carlisle, L E; Craford, P B; Davis, J

Many factors are involved in the selection of a profitable enhanced oil recovery process. The ability to achieve miscibility at low reservoir pressures, however, increases the options available to the petroleum engineer and perhaps may permit the installation of a profitable oil recovery process. Reservoir temperatures usually range from approximately 100 F up to more than 300 F depending primarily on the depth and the area located. In the application of an enhanced oil recovery program using miscible displacement, the goal is usually to achieve miscibility at the lowest pressure possible. Laboratory studies using carbon dioxide show that the miscibility pressure between a crude oil and carbon dioxide increases almost directly with a reservoir temperature. For example, at reservoir temperatures near 100 to 110 F, miscibility can be achieved for some crude oils at reservoir pressures as low as 1,200 psi. If the same crude, however, is at a temperature of 250 F, the miscibility pressure may be 2,500 to 3,000 psi. Many prospective oil reservoirs considered for enhanced oil recovery have undergone waterflooding, and the reservoir pressure is only about 1,000 to 1,500 psi. Consequently, to achieve miscibility, reservoir pressure may need to be increased so miscibility will occur. Reservoir pressure can be increased, but it requires time and the injection of considerable fluid. For large reservoirs the time required can be very long. Studies show that the pressure required to achieve miscibility using propane slugs decreases as reservoir temperature increases. For example, at temperatures of 100 to 110 F, a miscibility pressure of 2,000 to 3,000 psi might be required to achieve a 90% oil recovery. By contrast, if the reservoir temperature were 250 F, the miscibility pressure using propane slugs might be less than 900 psi.

• Research Organization: Texas A and M Univ., College Station, TX
• OSTI ID: 5154666
• Journal Information: Pet. Eng. Int.; (United States), Journal Name: Pet. Eng. Int.; (United States) Vol. 55:13; ISSN PEEID
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ALKANES
CARBON DIOXIDE INJECTION
COMPARATIVE EVALUATIONS
CONTROL
ENERGY SOURCES
ENGINEERING
ENHANCED RECOVERY
FLUID INJECTION
FLUIDS
FOSSIL FUELS
FUELS
HYDROCARBONS
MISCIBLE-PHASE DISPLACEMENT
OIL WELLS
ORGANIC COMPOUNDS
PETROLEUM
PRESSURIZING
PROCESS CONTROL
PROPANE
RECOVERY
RESERVOIR ENGINEERING
RESERVOIR FLUIDS
RESERVOIR PRESSURE
RESERVOIR ROCK
RESERVOIR TEMPERATURE
SOLUBILITY
WATERFLOODING
WELLS