METHOD FOR DEVELOPING A GEOLOGICALLY HETEROGENEOUS OIL RESERVOIR BY WATERFLOODING Russian patent published in 2022 - IPC E21B43/22 

FIELD: oil reservoir development.

SUBSTANCE: invention relates to a method for the development of a geologically heterogeneous oil reservoir by flooding. The injection of water and an aqueous polymer solution into injection wells is alternated. The selection of oil is carried out through producing wells. Alternating injection of water and aqueous solution is carried out in stages into injection wells of formation zones with improved reservoir properties, increasing the pressure in the formation due to the stage-by-stage injection of an aqueous polymer solution and subsequent forced injection of water. The pressure in the reservoir during the period of alternating injection of water and an aqueous solution of the polymer is increased at each stage and maintained at a level not higher than the opening pressure of geological and man-made fractures in the rocks that make up the reservoir. The duration of the alternating injection of a polymer solution and water is chosen based on hydrodynamic modeling of the impact on the reservoir. The ratio of the duration of the individual stages of injection of an aqueous solution of polymer and water is 0.25-3:1. During the period of forced water injection, a water-soluble nonionic or anionic surfactant is additionally injected into the formation. When an aqueous polymer solution is injected in reservoir zones with increased heterogeneity of the productive section in terms of permeability, a suspension of dispersed particles is additionally added to the polymer solution.

EFFECT: increasing pressure in the reservoir, optimizing the ratio of volumes and injection mode of the polymer solution and water, increasing the oil recovery factor from zones and reservoir intervals of different permeability.

5 cl, 1 tbl, 1 dwg