METHOD OF MULTI-FORMATION OIL DEPOSIT DEVELOPMENT WITH HORIZONTAL WELLS AND DOWNHOLE PUMPING Russian patent published in 2025 - IPC E21B43/20 

FIELD: mining.

SUBSTANCE: invention relates to the oil industry, in particular to the multi-formation oil deposit development methods, and can be used both at the early stage of development, and at the later one. Deposit is drilled with a grid of wells 350×350 m, performing its arrangement. Product is extracted from production wells. During operation measurements of oil and water production are made. Geological structure of deposit is specified, degree of non-uniformity is determined by area and section. Based on geological and hydrodynamic model in productive formation with oil-bearing thickness of 5.0-7.0 m horizontal production well is drilled with length of horizontal section of 300-400 m parallel to formation bottom and at 2.5-3.0 m from it. Deep perforation is performed along the whole horizontal section of the shaft. Each perforation hole is spaced from the previous one for not more than 15-20 m and the direction azimuth is not less than 40-50° from each other sub-perpendicular to main shaft. Available 15-27 holes are uniformly located along horizontal section of well shaft along spiral with depth of 1.5-2.0 m each. After oil treatment and achieving water cut of more than 98 % for efficient oil displacement, working agent is pumped from the underlying water-bearing donor bed into a horizontal borehole with deep perforation into the overlying oil-bearing acceptor bed with a constant flow rate equal to 1.1-1.3 times the volume of the produced oil. products from surrounding production wells. Pumping cycle makes 8 calendar days, then 2 days the injection well is idle. Pumping is stopped when water cut in production wells increases to 75% of initial water saturation. Resumed pumping of working agent only after reduction of water cut to 15% above initial water saturation. After working agent pumping is stopped till 75 calendar days average water cut of production in producing wells is determined. Average water cut is accepted as initial water saturation, and cycles of working agent pumping are continued as per the same principle, but based on new value of initial water saturation, which is periodically changed.

EFFECT: proposed method increases oil recovery factor due to maximum and uniform distribution of displacement agent in the formation and distribution of displacement front using cyclic cycle; it allows avoiding drilling of additional injection wells to the developed formation.

1 cl, 1 dwg