METHOD FOR WITHDRAWAL OF VISCOUS OIL FROM POOL Russian patent published in 1995 - IPC

FIELD: oil producing industry. SUBSTANCE: method for withdrawal of viscous oil from pool includes tapping the oil pool by system of injection and producing wells employing 5,7 or 9 spot well patterns. Rated amount of heat carrier is distributed between central injection well and producing well by the offered relation. Heat carrier is injected by cycles. Each cycle of heat treatment covers three stages. At the first stage, heat carrier is injects simultaneously into central injection well and into producing well which are alternating in arrangement, and product is withdrawn from the other producing wells located between them. Amount of introduced heat carrier is determined by the offered formula. At the second stage, producing wells through which heat was injected are changed over to product withdrawal, and producing wells through which product was withdrawn are changed over to injection of heat carrier in the amount equalling heat carrier introduced into unit of development at the preceding stage. At the third stage, producing wells through which heat carrier was injected are changed over to product withdrawal. Amount of heat carrier injected through central injection well is determined by the offered formula. Heat treatment cycle is repeated 3-5 times, and same amount of heat carrier is injected in each cycle. EFFECT: higher oil production due to increased coverage of formation with heat treatment. 2 cl, 2 dwg, 3 tbl