METHOD FOR DEVELOPING CARBONATE RESERVOIR OF VEREISKIAN-BASHKIR TARGETS Russian patent published in 2023 - IPC E21B43/20 

FIELD: oil industry.

SUBSTANCE: invention relates to methods for developing an oil field by increasing the reservoir sweep. The method for developing a carbonate reservoir of the Vereiskian-Bashkir deposits includes injecting a composition containing polyacrylamide PAA into the reservoir through a production well and extracting products through the production well. An injection well and an observation production well are preliminarily selected in the Vereiskian-Bashkir or Vereiskian or Bashkir target. The operation of the injection well is stopped, after 10 days a hydraulic fracturing is performed under pressure in the production well, as a fracturing fluid, a composition consisting of PAA and a composition of the following components, wt.%, is injected: cationic surfactant in an amount of 0.5-6.0 or its composition with an anionic surfactant in an amount of 2.0-5.0, erucyl-bis(2-hydroxyethyl) methylammonium chloride is used as cationic surfactant (EGAH), an anionic water-soluble polymer in an amount of 0.05-0.5, a low molecular weight salt in an amount of 1.0-8.0 with a monovalent cation, a cross-linking agent, which is used as salts of polyvalent metals in an amount of 0.002-0.05; the rest is water at a ratio of PAA and composition of 1:2, respectively, in a volume of 5-8 m³ per 1 m of the formation thickness. Then the proppant is pumped in the amount determined by the formula: G_pr = Q_scl·C_pr, where С_pr is the proppant concentration, kg/m³, Q_scl is the volume of sand-carrying liquid. As a sand-carrying fluid, a composition consisting of PAA and the composition indicated above is pumped at a ratio of PAA and composition of 1: 2, respectively, while the volume of the sand-carrying fluid is 15% less than the volume of the tubing string, and the proppant concentration is 40-45% of the volume of the sand-carrying liquid, the proppant is forced through with a composition consisting of PAA and the composition indicated above, at a ratio of 1:2, respectively, in a volume of 15-20 m³ per 1 m of the formation thickness. Next, swabbing is carried out at the production well, after four months, the injection well is launched.

EFFECT: efficiency of the method for developing the carbonate reservoir of the Vereiskian-Bashkir targets is increased by increasing the coverage of the formation by the impact, due to the connection of oil-saturated low-permeability interlayers due to the redistribution of injected water flows, no clogging of the oil-bearing part of the formation, the uniformity of the development of oil reserves, and the increase in the oil displacement factor.

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