High vertical conformance steam drive oil recovery method

Abstract

The vertical conformance of a steam drive process is improved and steam override reduced by penetrating the zone between one injection well and one producing well, with an infill well which is in fluid communication with the bottom half or less of the formation, and producing petroleum from the infill well after steam channeling has occurred at the production well; then converting the infill well from a producer to an injector and injecting steam into the lower portion of the formation via the infill well and recovering fluids from the production well. Two separate communication paths are established, one between the surface and the upper half or less of the formation, and one between the bottom half or less of the formation in the producing well, or in the infill well, or injection well, or combination of two or more thereof. A fluid having lower mobility than steam is injected into the upper part of the formation via one or more of the communication means after steam override has begun, to resaturate the steam swept zone with the low mobility fluid to prevent further steam flow therethrough and force steam to flow into unswept portions of the formation.