METHOD FOR CLEANING THE BOTTOMHOLE FORMATION ZONE OF AN INJECTION WELL AND A DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2023 - IPC E21B37/00 

FIELD: oil industry.

SUBSTANCE: inventions group relates to the oil industry, namely to cleaning the bottomhole formation zone of an injection well. When implementing the method, the lower end of the pipe string is lowered to a height of 1-1.5 m above the formation, the upper end is tied through a pipe valve and a tee with a pump unit and a nitrogen compressor unit. The annular valve is connected to the flow line, on which a safety valve, a device for switching the flow of the spout liquid in the form of a three-position switch, a choke tree equipped with choke lines, choke lines and a trough tank are installed in series. The liquid in the wellbore is replaced by a water-gas mixture, the cycles of pumping the water-gas mixture into the reservoir and pouring it into the trough tank are sequentially performed. The injection pressure of the mixture with each cycle is increased to the allowable maximum pressure on the formation or production string, when the maximum allowable pressure is reached, the safety valve provides pressure relief in the well, after it is activated, the water-gas mixture with impurities is poured out through the annulus through the fitting into the trough tank. The number of cycles corresponds to the number of nozzles with different diameters installed in the choke tree. The flow switch allows the nozzle to be switched from a larger bore to a smaller one. After the release of the "clean" water-gas mixture into the trough tank, the equipment at the wellhead is dismantled, the pipe string is allowed to reach the bottom hole and flushed with process fluid. The body of the flow switching device is made of cylindrical shape with inlet and outlet holes with a drum installed inside the body with the possibility of rotation, in which a through channel is made.

EFFECT: cleaning efficiency is increased, the occurrence of an emergency situation in the well due to water hammer is excluded, the implementation of the method and device is simplified.

2 cl, 5 dwg