TREATMENT METHOD OF BOTTOMHOLE ZONE Russian patent published in 2014 - IPC E21B43/16 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: method includes running-in of a pipe string into the bed perforation interval, flushing of the well equipped with the master and casing valves, treatment of the bottomhole zone by injection of a hydrochloric acid solution through the pipe string and a process holdup for reaction. According to the invention the pipe string is equipped by an impulse pulsator from below and by a valve above the impulse pulsator. The pipe string is run in into the well so that the lower end of the pipe string is located opposite the bed perforation interval, fresh water with addition of a surface active compound (SAC) is injected into the bed in a pulsed mode closing the casing valve under pressure that does not exceed permitted pressure to production casing with further spill and recovery of direct circulation. Then the valve is actuated and the impulse pulsator is cut off, the pipe string is run in additionally so that radial openings of the valve are located opposite the bed perforation interval. The hydrochloric acid solution is pumped through the pipe string until it reaches the bed perforation interval, a hydrochloric bath is set and the well is held. During the process holdup fresh water with SAC addition is injected each half an hour in sequence to the pipe string and a tubular annulus. After the holdup completion the reaction products are flushed from the well. An actual bed intake is determined by injection of fresh water with SAC to the bed through the tubing-casing annulus under pressure that does not exceed the permitted pressure to the production casing. If the actual bed intake is bigger or equal to the optimal intake then treatment of the bottomhole zone is stopped and the pipe string is run out from the well. If the actual bed intake is less than the optimal intake then at the open master and casing valves return circulation of the fluid is induced and the well is flushed. At that the master valve is closed periodically till the bottomhole pressure increases per 4 MPa from the initial value with further opening of the master valve till a transparent fluid appears. At that permitted pressure for production string is not exceeded. Return circulation is continued within 1 hour and then the actual bed intake is determined again.

EFFECT: improvement in efficiency of the bed treatment due to increase of the bed intake before its treatment, simplification of the method, reduction of costs and time of the bed treatment.

1 ex, 3 dwg