METHOD FOR DEVELOPMENT OF OIL FIELD Russian patent published in 1994 - IPC

FIELD: oil producing industry. SUBSTANCE: field is developed by stages. During the first stage, the field between rows of injection and producing wells is drilled additionally by horizontal holes. Exposed in water-injection wells are all producing intervals. In gas-injection wells, producing interval is exposed at its roof part. In producing wells, the foot part of producing interval is exposed. Gas injection is started through gas-injection wells closest to water-injection wells. Through remaining rows of gas-injection wells, oil is withdrawn from part of producing interval roof part. As gas breaks-through into remaining rows of gas-injection wells, they are subjected to gas injection. In this case, at the first stage, advancing gas repression of formation is effected. When formation pore volumes, displaced with water and gas, attains their equality, the second stage is started and advancing water repression of formation is effected. After break-through of gas and water cones to intervals of exposure of producing wells, the third stage is started. Then, all producing intervals are exposed and water injected through them. In so doing, gas-injection wells are changed over for withdrawal of injected gas and oil. Exposure of producing wells within the entire interval of producing formation and their injection with water provides for final recovery of residual unrecovered oil with no losses. EFFECT: higher oil recovery factor and more complete oil recovery from roof part of producing interval. 2 cl, 5 dwg