METHOD TO PREVENT SAND APPEARANCE IN OIL AND GAS WELLS Russian patent published in 2006 - IPC E21B43/22 

FIELD: oil and gas production, particularly to perform repair-and-renewal operations in wells to reduce sand ingress in well and to consolidate geological formations, including artificial ones after hydraulic formation fracturing.

SUBSTANCE: method involves injecting water-free liquid in well, wherein water-free liquid contains polyurethane pre-polymer and solvent; injecting water in well; hardening thereof. The polyurethane pre-polymer is hydrophobic polyurethane pre-polymer. The solvent is lower ketone. Above substances are taken in the following amounts (% by weight): hydrophobic polyurethane pre-polymer - 5.0-15.0, lower ketone - 85.0-95.0. Volume of the liquid is equal to 0.4-5.0 pore volumes. Injection time does not exceed 3 hours. After liquid injection the injection is stopped and well is left as it is for not less than 10 hours in static conditions to provide liquid hardening.

EFFECT: increased efficiency of sand appearance control without noticeable collecting properties decrease.

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