METHOD FOR ACID TREATMENT OF BOTTOM-HOLE ZONE OF PRODUCTION WELLS OF CARBONATE RESERVOIR OF BASHKIRIAN STAGE WITH UNDERLYING WATER FOR INTENSIFICATION OF OIL PRODUCTION Russian patent published in 2024 - IPC E21B43/27 C09K8/74 

FIELD: oil industry.

SUBSTANCE: in the method of acid treatment of the bottom-hole zone of production wells of the carbonate reservoir of the Bashkirian stage with underlying water for intensification of oil production first, formation thickness and distance to underlying flooded formation are determined. Section of formation with thickness of perforated formation less than 4 m, with distance to underlying flooded formation of 5–7 m and with distance between production wells of 250–300 m is selected, acid composition is then injected into the latter at open annular space in tubing strings in volume of 2–6 m³ per running meter of perforated thickness of the formation. Acid composition is squeezed with service water in the volume of the tubing string, then the valves in the tubing string and discharge of the annular space are closed and process exposure is carried out in the bath mode for 15 hours. Acid composition is used with the following ratio of components, wt %: hydrochloric acid with mass fraction of hydrogen chloride of 20–23 %—15.0; neonol AF9-6 or AF9-12 2.8; propyl alcohol 16.0; water—balance.

EFFECT: intensification of oil inflow, increase of injectivity of wells due to increase of depth of penetration of acid composition into formation and creation of branched network of fluid channels.

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