MISCIBLE OIL FLOODING AT CONTROLLED VELOCITIES

摘要

MISCIBILE OIL FLOODING AT CONTROLLED VELOCITIES (D#78,120 -F) The disclosed invention is a method of conducting a miscible flood with a flooding medium predominantly composed of carbon dioxide or nitrogen in a shorter period of time with acceptable hydrocarbon recovery. The invention is practiced by injecting a predominantly carbon dioxide or nitrogen medium into the underground hydrocarbon reservoir at such a rate as to produce a frontal advance velocity in the reservoir of about 2 to about 15 times the critical velocity of flow for that flooding medium through the instant reservoir. This high flooding velocity, substantially above critical velocity, is maintained until the flooding front has traveled about 60% to about 90% of the distance from the injection to the production systems. At this time, the frontal advance velocity is reduced to a value approximately equal to or less than the critical velocity for the remainder of the miscible flood.