METHOD OF TREATMENT OF THE NEAR-WELLBORE ZONE Russian patent published in 2023 - IPC E21B43/27 E21B43/22 E21B49/00 

FIELD: oil production.

SUBSTANCE: in the method of treatment of the near-wellbore zone, before treatment is performed, pressure testing of the tubing string of tubing with a downhole pump is performed at least a day before. A back pressure of 8 MPa is created in the tubing string with a pump to determine the tightness and prevent the acid composition from flowing through the pump into the tubing. The pipe space is closed off from above. Then, an injection test is performed, a process fluid is pumped into the annular space, the fluid being formation water with a density of 1.0-1.18 g/cm³ at 20°C containing 0.1-0.2% surfactant ML 81B, in double the volume of the annular space with a flow rate of 0.1-2.0 m³/min or an emulsion with a flow rate of 0.1-0.25 m³/min, being a water-oil emulsion containing commercial oil or oil from a well with a water content of not more than 10%, emulsifier MIA-prom grade B, reservoir mineralized water with density at 20°C 1.16-1.18 g/cm³, or an oil-free emulsion containing the ITPS-013G emulsifier, which is a complex of surfactants based on a hydrocarbon solution of alkanolamine esters of oleic acid, and mineralized water with specific weight of 1.07-1.18 g/cm³. Taking into account the previously performed treatments with low wellhead pressures, depending on the specific injectivity coefficient, the injection volume is selected. When the pressure rises during the injection process, the injection is stopped and the time it takes for the pressure to drop is determined. If the pressure drops to 0 atm in more than 5 minutes, recalculation is carried out to reduce the volumes, solvent consumption and acid composition, and the viscosity of the diverter fluid. If there is no increase in pressure, the entire volume is prepared and pumped without stopping until signs of a stable increase in pressure appear, the results of the injection test are entered into the computer program and the volume and viscosity of the diverter fluid, the rock fracture gradient, permeability, the optimal ratio of the diverter fluid volume to the acid composition volume, and volume of the process fluid are determined. Then changes are made to the design of the project. At least one pumping cycle is performed - sequential injection of a diverter fluid with a viscosity of 600-2000 cps with a flow rate of 0.1-0.25 m³/min, a solvent with a flow rate of 0.1-0.2 m³/min, an acid composition with a flow rate of 0.1-2.0 m³/min with a specific volume of 1-10 m³ per 1 meter of the perforated interval, and the solvent is pumped in a volume of at least 4% of the volume of the diverter fluid, and a water-oil emulsion is used as the diverter fluid containing commercial oil or oil from a well with a water content of not more than 10%, emulsifier MIA-prom grade B, reservoir mineralized water with a density at 20°C 1.16-1.18 g/cm³, or an oil-free emulsion containing the ITPS-013G emulsifier, which is a complex of surfactants based on a hydrocarbon solution of alkanolamine esters of oleic acid, mineralized water with a specific gravity of 1.12-1.18 g/cm³. Squeezing is carried out with process fluid in a volume equal to the volume of the annular space at a flow rate of 0.1-2.0 m³/min. After the response, the well is tied with a trough system, the well is put into operation and worked into the trough system by pumping in a double volume of displacement fluid until a well product with a pH of more than 4 is obtained.

EFFECT: increase in efficiency of treatment of the near-wellbore zone.

2 cl, 7 tbl