METHOD OF PERFORMING WATER-SHUTOFF OPERATIONS IN WELL Russian patent published in 2002 - IPC

FIELD: oil and gas production; applicable in well servicing with use of inserted-joint long pipe, mainly, under conditions of well repairs in permafrost rocks. SUBSTANCE: method includes lowering of inserted-joint long pipe string into cavity of tubing string; injection of space fluid, inert relative to water-shutoff composition, into inserted-joint long pipe string in amount of 0.3-0.5 cu.m; injection of water-shutoff composition in rated volume and the second portion of spacer fluid in amount of 0.2-0.3 cu.m; forcing of water-shutoff composition and spacer fluid. Forcing of said materials is carried out by two independent pumping units which inject spacer fluid into inserted-joint long pipe string, tubing and casing strings. Process of injection of displacing fluid by both pumping units is continued up to full displacement of water-shutoff composition from inserted-joint long pipe string and penetration of water-shutoff composition into formation. Operation of the second pumping unit injecting displacing fluid into annular space between tubing and casing is discontinued. Cavity of tubing string is communicated by means of throttling device with discharge line running from well. Injected into inserted-joint long pipe string is washing fluid in volume sufficient for its cleaning from used components. Annular space of casing string is sealed. Discharge line is closed and well is allowed to stand under pressure for tie needed for reaction of water-shutoff mixture. EFFECT: higher efficiency. 3 cl, 1 dwg