WELL BOTTOMHOLE ZONE TREATMENT METHOD Russian patent published in 2019 - IPC E21B43/25 E21B43/27 E21B28/00 

FIELD: oil and gas industry.

SUBSTANCE: method for treatment of bottomhole zone involves lowering of pipe string equipped with packer, device for pulse pumping of liquid, destructible valve, perforated branch pipe with bushing inside and locking ring above breakable valve, in interval of formation perforation. Also, this method comprises the solvent injection through the pipes string in the continuous mode with a flat packer, well with solvent technological exposure, four cycles of the process fluid injection into the reservoir through the pipes string and the well annular space, the solvent and the reaction products washing out by backwashing. For the fluid pulsed injection by the pipe string raising, installing the fluid impulsive injection device opposite the formation bottom and a packer is fitted. Then moving the bushing down relative to the perforated branch pipe and sealing the perforated pipe holes. Excess pressure of process fluid is used to cut the destructible valve, pumping of 10–15 % aqueous solution of hydrochloric acid into the bed is performed in pulsed mode, and pulsed treatment is performed with this solution. Further, process holding is performed for reaction and extraction of reaction products by swabbing. Novelty is that sealing of holes of perforated branch pipe is carried out by moving sleeve down to stop in stop ring of this branch pipe. Sleeve is installed between the branch pipe and the bushing and fixed on the branch pipe and on the bushing by shear screws. Note here that shear strength of shear bolt securing the sleeve on the branch pipe is less than the shear strength of such screw fixing the sleeve on the sleeve. Sleeve is moved down to outlet of cartridge case by creation of hydraulic pressure in pipe string after discharge into ball tube string. Ball closes bore of sleeve. From the bottom end of the bushing there are radial slots for passage of 10–15 % aqueous solution of hydrochloric acid from the cavity of the case into the device for pulse pumping of liquid.

EFFECT: reduced time for treatment of the formation of the well due to reduced duration of preparation of the process of pumping hydrochloric acid solution into the formation in pulse mode.

1 cl, 2 dwg