Steam-gas injection strategies for improving oil recovery from bottom water reserviors

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:141367

Nasr, T N; Pierce, G ^[1]

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1. Alberta Research Council (Canada)

A series of steam-gas injection experiments was conducted in a high temperature, high pressure scaled model to evaluate strategies for improving steamflooding performance in bottom water reservoirs. The scaled model simulates 1/8 of a five-spot pattern for a Cold Lake oil sand deposit of 12.8 m thickness underlaid by a 2.2 m bottom water zone. The bottom water zone was initially 100% water saturated. The gases used with steam were carbon dioxide, flue gas (88% N{sub 2} + 12% CO{sub 2}) and N{sub 2}. Injection strategies included steam-gas continuous injection and gas soak prior to steam injection. The effect of bottom water zone permeability on the recovery process was also determined. The results indicate that co-injection of a gas with steam has the potential to accelerate the initial hot communications between the injection and production wells due to a hot gas channelling. This accelerates and improves oil recovery rates during the initial stage of the process. The combination of of CO{sub 2} and N{sub 2} in steam resulted in a better performance than that from steam-N{sub 2} or steam-only injection. Injection of a high concentration of gas in steam can have an adverse effect to oil recovery and oil-to steam (OSR). Soaking the reservoir with carbon dioxide prior to steam injection can result in an injectivity problem of the bottom water zone had an impact on the process. Increasing the bottom water zone permeability from 1.3 to 11 {mu}m{sup 2} resulted in a decrease in final oil recovery from 80% to 70%.

• OSTI ID: 141367
• Report Number(s): CONF-930304--
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
COLD LAKE DEPOSIT
ENHANCED RECOVERY
GAS INJECTION
OIL SANDS
OPTIMIZATION
PETROLEUM
SCALE MODELS
STEAM INJECTION
WATER RESERVOIRS