METHOD FOR COMPLETING AND INTENSIFYING INFLOW OF WELL WITH CARBONATE RESERVOIRS Russian patent published in 2021 - IPC E21B43/25 E21B43/27 E21B43/114 

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry, in particular to the completion and intensification of an obliquely directed well drilled on carbonate reservoirs of small thickness near a water-saturated reservoir, it is also used during acid treatments during current and major repairs of the well. The method includes opening the productive reservoir by drilling, lowering the production column, cementing the back-hole space, lowering the layout of pump and compressor pipes (hereinafter – PCP) with a hydro-mechanical piercing perforator into the well. The perforating knives of the perforator are located in the interval of the carbonate oil-saturated reservoir. The piercing hydro-mechanical perforation is performed at a distance from the water-saturated reservoir, which excludes the breakthrough of the lower waters when the injection pressure increases to 15 MPa. After each point of piercing, through the perforator and the formed perforation holes, the caverns are washed with technical water with a density of 1.05-1.16 g/cm³ for 10-15 minutes to pump water in a volume of 2.5-3 m³ with a flow rate of 3.5-4 l/sec under a pressure of up to 20 MPa. The process of piercing and cavern washing is carried out every 0.2 m in the oil-saturated part of the reservoir. Swabbing is performed before acid injection until the bottom-hole pressure reaches 2 MPa with registration of the reservoir inflow parameters. In the absence of back-hole circulation or watered products, the perforator is lowered below the level of the lower perforation hole. Hydrochloric acid is pumped through the PCP through the hole above the perforator. Acid treatment is carried out in two stages. At the first stage, hydrochloric acid of 15-24% concentration is injected in a volume of 1-1.5 m³ per 1 m of reservoir thickness, pressed with technical water with a density of 1.05-1.16 g/cm³ with a pressure of 3 MPa with a stepwise increase in pressure of 1 MPa, and then held in the acid bath mode for 15-60 minutes until a pickup of 0.5 l/sec at a pressure of 3-5 MPa is reached, without exceeding the pressure of the column pressure. After the acid reaction for 3-4 hours, the well is swabbed with the selection of a volume equal to the sum of the well volume, the injected acid volume and the pressure liquid volume. The second stage of treatment is carried out by injection of hydrochloric acid of 15% concentration in a volume of 3-6 m³ per 1 m of oil-saturated reservoir thickness. The acid is pressed into the reservoir at a pressure of 3 MPa with technical water with a density of 1.05-1.16 g/cm³, treated with a surfactant in a volume of up to 15-20 m³ per 1 m of the reservoir thickness with a stepwise increase in pressure of 1 MPa, and held in the acid bath mode for 15-60 min until a pickup of 0.5 l/sec at a pressure of 3-5 MPa is reached. After the acid reaction, the well is developed for 4-8 hours.

EFFECT: invention provides for increased efficiency of the method by increasing the duration of the processing effect, reducing the water content of the well products, as well as expanding the technological capabilities of the method.

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