High vertical conformance steam drive oil recovery method

摘要

The vertical conformance of a steam drive process is improved and steam override reduced by penetrating the recovery zone between one injection well and one producing well, with at least one infill well which is in fluid communication with no more than the bottom half of the formation. Steam or a mixture of steam and hydrocarbon is injected into the injection well and fluids including oil are recovered from the producing well until live steam production occurs at the producing well. Petroleum production is then begun at the infill well and continued until the water cut of the fluids being produced from the infill well reaches 95 percent. The infill well is converted from a producer to an injector and hot water or cold water followed by hot water is injected into thelower portion of the formation via the infill well and fluids are produced from the production well. By this means, oil is recovered from the lower portions of the formation between the infill well and the production well. After water breakthrough occurs at the production well, steam is injected into the infill well and fluids are recovered from the production well. Hydrocarbon solvent is injected either as a slug prior to steam injection into the infill well or comingled with the steam being injected into the infill well. By this multi-step process involving the infill well, the amount of oil recovered from the portion of the formation in the recovery zone defined by the injection and production well is increased significantly.