METHOD OF PROPPANT WASHING FROM PIPE STRING AND BOTTOM-HOLE ZONE AFTER RESERVOIR FRACTURE Russian patent published in 2017 - IPC E21B37/00 

FIELD: oil and gas industry.

SUBSTANCE: method includes the pipes string with the packer run in the well into the reservoir interval, installation of the packer over the reservoir, the fracture fluid injection into the productive reservoir, conduct the reservoir drainage, removing the fracturing fluid from it and the loose proppant in the reservoir into the well, then the coiled tubing - CT run through the pipes string and the proppant washing from the well. The lower end of the pipes string is equipped with the pressure fitting seat. Before the reservoir hydraulic fracturing (RHF), the pipe string is pressurized at the pressure exceeding the expected fracture pressure by the factor of 1.5. After providing the RHF and draining of the fracture fluid and the loose proppant from the reservoir into the pipe string, provide the CT string run with the feather at the end and wash the proppant from the well in two stages. At the first stage the CT string is run up to the pipe string pressure fitting seat. Then the process fluid with the viscosity of 1.0 to 2.0 MPa⋅ wash the proppant from the pipes string. Then the CT string column is run to the bottom hole and the proppant is washed out from the well bottom-hole zone by the thickened process liquid with the viscosity from 6 to 8 MPa⋅. After that raise the CT string up to the depth of 100 m, hold the pause for the process residue of particles, determine the bottomhole by the repeated CT string run with the feather.

EFFECT: increase of the washing reliability and quality, the method realisation is simplified.

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