METHOD FOR DEVELOPMENT OF MULTI-FORMATION OIL DEPOSITS WITH CIRCULAR PRODUCTION WELL IN MIDDLE OF ELEMENT AND HORIZONTAL INJECTION WELLS Russian patent published in 2025 - IPC E21B43/30 E21B43/20 E21B43/14 E21B47/00 

FIELD: mining.

SUBSTANCE: invention relates to a method for development of multi-formation oil deposits with a circular production well in the middle of the section and horizontal injection wells. Method includes geophysical researches in wells and determination of section of multi-formation deposit with interlayers coinciding in the structural plan, and determination of formation pressure, which in each of interlayers excludes hydrodynamic connection between them at connection. Method also includes collecting oil samples for analysis. At the selected section, performing the horizontal injection wells drilling in parallel to the oil bearing outline and/or the manifold replacement lines and at distance of 80-100 m inside the deposit from the oil bearing outline and/or the manifold replacement lines, bottomhole of the previous well and the point of entry into the formation of the next well are placed at distance of 200-250 m from each other. Horizontal borehole is drilled with length of 2.2-2.5 of distances of the approved grid of wells and put into operation. When formation pressure drops by 15-20% from the initial value and/or when horizontal wells started for production are watered, more than 97% of them are switched to injection. In central part of selected section, drilling of circular production well is performed with entry into formation and angle set of 3.5-4°, with exit to circumscribing circle radius of 250-300 m, with deep perforation. Each perforation hole is spaced from the previous one by not more than 8 m. Well bottom is as close as possible to the circular shaft and not more than 40-50 m from it, in this case having 42-50 holes arranged evenly along the well shaft along a spiral with depth of 1.5-2 m, and each with a varying direction of perforation as the producing shaft deepens, controlling the wellbore according to the GIS, carried out after its drilling so that in the upper and/or upper interlayers the perforation and/or perforations are oriented downwards at an angle to wellbore 50-60°. In the following interlayers, changing the angle before flattening to the horizontal and further raising the direction of the perforation hole to overlying and/or above-lying interlayers, while maintaining a circular well radius of 200-250 m from the inlet point to the bottomhole, and with a branch from injection horizontal wells located parallel to the oil bearing circuit and/or the manifold replacement lines, at 250-300 m from them to prevent breakthrough of injection agent to producing perforated spines of shaft and to production shaft and possibility of maximum oil production at deposit section by pumping displacement agent into injection horizontal wells. Displacement fluid is pumped into horizontal injection wells and products are extracted from circular production well. During operation oil and water production and injection are measured.

EFFECT: increasing oil displacement efficiency, increasing recovery of oil reserves both in square area and in section.

1 cl, 1 dwg