METHOD OF ACID TREATMENT OF BOTTOM-HOLE FORMATION ZONE WITH CARBONATE RESERVOIR Russian patent published in 2012 - IPC E21B43/00 

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of bottom-hole formation zone with carbonate reservoir includes two pumping cycles of 10-15 % water solution of chlorhydric acid using displacement fluid. Each cycle contains pulse pumping of solution under pressure of 1-4 MPa, pumping of this solution under constant pressure, process exposure equal to 2.5-3.5 hours for reaction, and extraction of reaction products followed by bottom-hole cleaning with flushing fluid. Duration of solution pulse pumping is up to 5 min, duration of stops is 6-10 min. Under constant pressure pumping is performed in portions 2-4 m³ each with exposure between portions equal to 2-4 hours. At that pumping of solution portions is stopped under pumping pressure increasing 3 MPa. Second cycle of acid treatment is performed after reducing of well flow rate by 30-50 %. As displacement and flushing fluid oil is used.

EFFECT: increasing efficiency of treatment of bottom-hole zone of well and increasing well productivity.

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