METHOD FOR DEVELOPMENT OF OIL DEPOSIT BY HORIZONTAL WELLS Russian patent published in 2024 - IPC E21B43/18 E21B43/26 

FIELD: mining.

SUBSTANCE: invention relates to a method of developing an oil deposit by horizontal wells. Method includes determining directions of maximum permeability of oil-saturated rocks. Also includes drilling of production wells with horizontal shafts in direction maximum permeability with multistage hydraulic fracturing. It also involves drilling of additional horizontal wells perpendicular to direction of maximum permeability of oil-saturated rocks and between fractures of hydraulic fracturing with deep perforation along the entire horizontal borehole. Initial formation pressure, direction of maximum permeability of oil-saturated rocks and oil-water contact (OWC) are preliminary determined, horizontal shafts of production wells are drilled with azimuth shift of not more than 20° in direction of maximum permeability of oil-saturated rocks or in their direction, production of products from production wells is performed. If the product is flooded by more than 98%, production wells are transferred to injection wells; multi-stage hydraulic fracturing is performed with creation of fractures perpendicular to the borehole. Additional production wells are drilled with horizontal shafts with a length of at least 350 m and/or a length corresponding to the distance between two additional horizontal wells, horizontal shafts of production wells are located perpendicular to direction of maximum permeability of oil-saturated rocks, parallel to OWC at a distance of at least 3 m from the OWC and between hydraulic fracturing cracks with a distance greater than 150 m from the trajectory of the hydraulic fracturing cracks, perforation is performed along the whole horizontal borehole along a spiral with depth of 1.8-2.0 m each hole and distance from each other from 8 to 10 m in each well. At 40% decrease of formation pressure from initial formation pressure in the transferred injection wells, water injection into the formation with volume of 1.2 of the volume of the produced product is started, maintaining the formation pressure at the initial level.

EFFECT: provision of uniform oil displacement from oil-saturated formation, high rate of oil extraction and increase of well productivity.

1 cl, 1 dwg, 1 tbl