METHOD FOR ACID TREATMENT OF CARBONATE FORMATION Russian patent published in 2016 - IPC E21B43/27 

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry. Method for acid treatment of carbonate formation includes separation of treatment intervals in carbonate formation, opened by well with open hole in oil-saturated rocks. Then string of flexible tubes (FT) is equipped with, bottom to top: jet nozzle, hydraulic deflector and limiter; FT string is lowered into well and hydraulic deflector is installed opposite selected treatment interval of open horizontal borehole, closest to well bottom. Then side channels are made: pressure is created in hydraulic deflecting device by pumping of 22 % hydrochloric acid solution in water into FT string, hydraulic deflector turns and presses jet nozzle against wall of open hole. Hydraulic pressure in FT string is increased and generation of rock is performed to form first side channel with simultaneous lowering of FT string at rate of 0.05 m/s, until limiter stops against wall of open hole. Then pressure in FT string is reduced down to zero, and FT string is removed from first side channel into open hole. Excess pressure created anew in hydraulic deflector by pumping 22% hydrochloric acid solution in water into FT string, hydraulic deflector is turned at 90° along perimeter of open hole, and presses jet nozzle against wall of open hole. After that from interval with first side channel, second side channel from open hole is similarly performed, then FT string is removed from second side channel into open hole. Similarly, in one range third and fourth side channels of open hole are performed. After performing four side channels, 22% hydrochloric acid aqueous solution is replaced by 10% solution, and similarly, by successively turning hydraulic deflector to 90° and axially moving FT string in side channel along perimeter of open hole in turn, acid exposure in all four side channels is performed, with creation in each side channel branched network of artificial fracturing; acid treatment of carbonate formation in rest of selected treatment intervals in oil-bearing rocks of carbonate formation is performed similarly.

EFFECT: technical result is increased efficiency of processing, increased oil recovery, higher reliability of method implementation.

1 cl, 7 dwg