METHOD OF PREPARATION AND PERFORMANCE OF WELL SERVICING Russian patent published in 2002 - IPC

FIELD: oil and gas producing industry. SUBSTANCE: preliminarily arranged in space between casing and tubing is additional pipe string. Round-trip operations are performed after disconnection of pump in well and pumping by multiphase pump of well fluid over channel formed by casing and additional pipe string to oil accumulator up to attaining atmosphere pressure in well, with subsequent dismantling of wellhead equipment. Pumping-out of well fluid is carried out during the entire process of round-trip operations. Multiphase pump capacity is above 40 cu.m/h. Additional pipe string is lowered through 1/10 part of well length. Method is used in preparation of well for servicing and workover, for prevention of change of filtering characteristic of bottom-hole formation zone, higher efficiency of well completion after performance of servicing, simplification of repair and restoration work, and acceleration of workover and servicing of well due to reduced time for swell washing. EFFECT: preserved reservoir properties of formation, eliminated repair-restoration operations. 2 cl, 1 dwg