METHOD FOR DEVELOPMENT OF OIL FORMATION WITH NON-UNIFORM PERMEABILITY Russian patent published in 2020 - IPC E21B43/22 C09K8/88 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to development of an oil deposit and can be used in development of an oil deposit with inhomogeneous permeability beds for adjustment of injectivity profile of an injection well. Invention comprises method for development of heterogeneous permeability of oil formation. Proposed method comprises successive pumping of water solution into injection well and shutdown of well for process exposure. Aqueous solution of the first fringe contains polyacrylamide – 0.51–0.8 wt%, a cross-linking agent (chromium acetate – 0.04–0.06 wt%, zinc oxide – 0.04–0.06 wt%), water – balance. After pumping of the first fringe, the well is stopped for process exposure for two to three days. Then the second fringe of water solution is pumped. Water solution of second fringe contains polyacrylamide – 0.3 wt%, amphoteric surfactant – 0.3–5.0 wt%, water – the rest. Ratio of the first and second fringes is 1:(1÷5). Amphoteric surfactant used is betaine BETAPAV AP 18.30 amphoteric surfactants – water-alcohol solution of oleylamidopropyl betaine, or BETANOR™ Alkylamidopropyl betaine of grade A, B, or Neominol A, B detergent composition, or Bixol A detergent composition.

EFFECT: by increasing the filtering resistance by creating a blocking screen by pumping a gel-forming polymer solution and wider involvement in development of low-permeable oil-saturated zones of the formation by pumping polymer solution and an amphoteric surfactant, the method is more efficient.

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