METHOD FOR DEVELOPMENT OF WEAKLY PERMEABLE OIL DEPOSIT WITH APPLICATION OF HORIZONTAL WELLS AND WATER AND GAS IMPACT Russian patent published in 2019 - IPC E21B43/20 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry and can be used in development of weakly permeable oil deposit with application of horizontal wells and water and gas impact. Proposed method comprises drilling of horizontal wells, separation of horizontal shafts by packers, pumping working fluid into injection wells with creation of vertical lateral displacement, extraction of products from production wells. Deposit with total oil-saturated thickness of the formation is selected to be not less than 50 m. At least one pair of horizontal wells is drilled, i.e. producing and discharge wells. Horizontal barrel of the injection well is placed near the roof of the productive formation. Production well horizontal bore is arranged near formation bottom in absence of water-oil contact and at distance of at least 10 m from water-oil contact at its presence. In the horizontal plane, horizontal shaft axes are located at a minimum distance of 250–500 m at an angle of not more than 45° to each other, and in vertical plane – at a distance depending on thickness of formation, and at an angle of not more than 15°. After initial withdrawal of formation product and reduction of formation pressure to level not lower than pressure of oil saturation with gas, injection wells are started to conduct joint and / or sequential pumping of water and gas. Ratio of water and gas is determined from results of laboratory studies on oil displacement and hydrodynamic modeling with volumes of water and gas available for pumping in the area of the given deposit and with achievement of maximum oil yield. Breakthrough of working agent to production wells, as well as prevention of reduction of formation pressure below oil saturation pressure with gas is controlled by modes and operating time of all wells of the deposit.

EFFECT: higher oil recovery.

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