METHOD OF WELL BOTTOM ZONE PROCESSING Russian patent published in 2014 - IPC E21B43/27 

FIELD: oil-and-gas industry.

SUBSTANCE: invention relates to oil industry. Proposed method comprises perforation of productive bed interval. Acid solution is injected at packed annulus. It is held, swabbed at packed annulus to bottomhole pressure reduction by at least 1.7 MPa and rate of inflow from productive bed of at least 80 m/h. Acid with surfactant is injected in productive bed at decreased bottomhole pressure. Processed interval is driven with process water in amount of 1.4-1.6 m³/m with density of at least 1.15 g/cm³ at the rate of about 1-2 l/s at initial wellhead pressure of 10-11 MPa. Injection is performed at the rate of 4-5 l/s at injection pressure reduction to 8-9 MPa and held to pressure drop. Acid is held for reaction for at least one hour, swabbed and well is flushed. Downhole pump equipment is lowered to start the well. Said process water represents the solution of sweet water or formation fluid with density of 1.0-1.18 g/cm³ with addition of 0.1-0.5% solution of surfactant ML-81B.

EFFECT: increased processing depth, higher efficiency.

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