Patent ID: 6257334
Filing Date: 2001-07-10
Classification: E21B

Abstract:
A thermal process for recovering heavy viscous oil from a subterranean reservoir, comprising:(a) providing a pair of spaced apart, generally parallel and co-extensive, generally horizontal steam injection and production wells;(b) establishing fluid communication between the wells;(c) practising steam-assisted gravity drainage to recover oil by injecting steam at less than formation fracture pressure through the injection well and producing steam condensate and heated oil through the production well while throttling the production well to keep the produced liquid temperature less than the steam saturation temperature at the injection well;(d) providing a generally horizontal third well, offset from and generally parallel and co-extensive with the injection and production wells; and(e) contemporaneously practising cyclic steam stimulation at the offset well to develop lateral heating of the span of reservoir formation between the pair of wells and the third well and periodically producing heated oil and steam condensate therethrough.