METHOD FOR DEVELOPMENT OF MULTILAYER OIL DEPOSIT WITH CIRCULAR INJECTION WELL IN MIDDLE OF SECTION Russian patent published in 2025 - IPC E21B43/14 E21B43/30 

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry, namely to development of oil deposits, productive formations of which consist of several interlayers coinciding in structural plan. Disclosed is a method of developing a multi-formation oil deposit with a circular injection well in the middle of the section, which includes determining interlayers with different permeability, drilling injection and production wells, injection of displacement fluid into each interlayer through injection well and production of deposit from each interlayer through production wells. At that, the injection well is made circular with an entrance to the formation and a set of angle 4° by 10 m and deep perforation. At that, each perforation hole is spaced from the previous one by not more than 10 m, having at least 25-30 holes located evenly along the borehole along the spiral, with depth of 1.5-2.0 m each with varying direction of perforation as the injection borehole deepens. At that, according to results of hydrodynamic study carried out after completion of drilling of circular injection well, perforation holes in interlayers are oriented downwards or upwards at an angle to well shaft 60-70°, leaving 50-70 m from the inlet point to the bottomhole of the circular well to displace oil from the circle of the injection well to the producing vertical wells. Production wells are drilled inclined from vertical along the perimeter of the deposit section. In this case, if the upper interlayer has a lower permeability, and the lower interlayer has a higher permeability, the production well is built with distance as far as the deepening from the circular shaft of the injection well, and when the upper interlayer has high permeability, and the lower interlayer has less permeability, the production well is constructed with approaching as far as deepening to the circular shaft of the injection well.

EFFECT: increasing drainage of the productive formation in each of the heterogeneous interlayers along the section by increasing the volume of the drained rock around the circular shaft of the injection well, providing a uniform profile of injectivity in all interlayers.

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