WELL BOTTOMHOLE ZONE TREATMENT METHOD Russian patent published in 2019 - IPC E21B43/20 E21B43/25 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil industry and can be used in the acid treatment of wells. Method of processing the well bottom zone includes lowering a pipe string into the perforation interval of the reservoir, injecting a hydrocarbon solvent and stopping the well for process holding. At that the pipe string is equipped with a device for impulsive injection of a liquid, destructible by a valve, a perforated nozzle with a sleeve inside and a packer. Perforated pipe set below the lower perforation interval of the reservoir. Hydrocarbon solvent is pumped through a string of pipes in a continuous mode with no packer. Technological exposure is carried out in 4 cycles. At that every 20 minutes, the process fluid is pumped alternately into the column of pipes and annular space of the well. Wash back the hydrocarbon solvent and the reaction products. Devices for pulsed injection of fluid set against the bottom of the reservoir. Packer seating is performed. Seal the holes of the perforated pipe by moving the sleeve down. Pipe string is filled with process fluid. They create excess pressure and cut off the destructible valve. 10–15 % aqueous solution of hydrochloric acid is pumped in and pulsed. Gradually increase the flow rate of the injection solution. Perform technological exposure. Reaction products are swabbed. An aqueous solution of hydrochloric acid is pumped in a foamy state. For the formation of foam a device for pulsed injection of fluid is used. Case of the specified device is performed in the form of a hollow cylinder with annular grooves on the inner wall. Each groove in cross section has the shape of a rectangular trapezoid with a short base at the bottom of the groove and an inclined wall at the top. Inside the housing have a hollow axis having a bottom with a hole. Screw is pressed into the hole in the bottom of the hollow axis. On the hollow axis with two bearings set sleeve. Sleeve and the hollow axis is performed with slit slots located at an angle to their forming. Slit slots of the sleeve are located in the opposite direction to the slit slots of the hollow axis. On the lower end of the inner wall of the hollow cylinder fix the disk. Disk is performed with holes remote from the center at the same distance. At the same time on the upper wall of the disk between the inner wall of the hollow cylinder and the holes of the disk have a radially directed plate. Opposite the lower end of the hollow axis, radially directed plates in the form of a rectangular trapezium with an inclined side at the top and a short base in the central part of the disk are rigidly fixed onto the wall of the disk between the holes of this disk.

EFFECT: increase the efficiency of wellbore zone treatment.

1 cl, 4 dwg