METHOD FOR ELIMINATION OF LEAKAGE OF STRINGS OF OIL AND GAS WELLS Russian patent published in 2016 - IPC E21B33/138 C09K8/508 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to methods of elimination of leakage of strings of oil and gas wells, and can be used for recovery of tightness of production strings of oil and gas wells by elimination of drill string and pressure behind the sources of occurrence of which are gas leaks at non-tight threads said columns and micro cracks of cement stone. Method includes well killing, installation of cement bridge in it, blowing well gaseous agent till complete drying of pipes in well and to maintain pressure in well of gaseous agent exceeding bed pressure not less than 1.0 MPa. At that, gaseous agent is selected from group of gases: nitrogen, exhaust gases of internal combustion engine, carbon dioxide. Sealing composition is pumped into annular space, which is mixture of modified epoxy resin or modified silicone resin with hardener, from which by means of cement plug productive formation-collector is protected for preservation of its filtration-capacitance properties. Well is maintained for time required for movement of sealing compound to bottom hole with further blowing of well with previously selected gaseous agent until complete removal of excess sealing compound from annular space of well. In process laying over well is held for at least two days with further drilling of cement plug, installation of operational equipment and well development.

EFFECT: elimination of leakage of strings of oil and gas wells, increased reliability of operation of gas wells using physical and chemical effects, prolonged action of sealing non-tight columns and channels connections in cement stone.

1 cl, 7 dwg, 4 tbl