| 摘要 |
Extn. of oil from underground formations contg. a liq. oil phase satd with gas, by simultaneous and separate injection into the top of the formation of (A) a light hydrocarbon solvent, and (B) a heavier hydrocarbon solvent, until a mixed slug is formed with direct or limited miscibility with the oil phase under the prevailing temp. and pressure. A driving fluid is then injected to displace the oil phase downwards and out through a production borehole. Miscibility with the oil phase is maintained. The process is suitable for use at pressures below the gas satn. pressure, in presence of a gas cap above the oil, and re-pressurising the formations to above the gas satn. pressure is unnecessary. |
