METHOD OF FORMATION BOTTOMHOLE ZONE ACID TREATMENT Russian patent published in 2012 - IPC E21B43/27 

FIELD: oil and gas production.

SUBSTANCE: method of formation bottom-hole zone acid treatment includes two pumping cycles of 10-15% water solution of hydrochloric acid with the use of displacement fluid each containing pulse solution pumping at 1-4 MPa, pumping of this solution at constant pressure, technological exposure for 2.5-3.5 hours for reaction and reaction products removal with further bottom-hole cleaning by flushing fluid. Solution pulse pumping is carried out for 5 minutes with 6-10 minutes breaks. Pumping at constant pressure is done by portions of 2-4 m³ with holding 2-4 hours between portions. Pumping of solution portions is stopped at pumping pressure exceeding 3 MPa. Between solution pumping cycles there pumped is oil-acid composition containing 24-26% solution of hydrochloric acid in oil with volume of 1-4 m³ at 7 MPa. Oil is used as displacement and flushing fluid.

EFFECT: increase of well bottom-hole zone treatment efficiency and increase of well productivity due to increase of acid treatment covering of entered formation.

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