METHOD FOR GASSING OFF OIL-GAS WELL Russian patent published in 1998 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this prevents undesirable oil and gas appearance and improves quality of cementation of wells. According to method, plugging solution is injected into annular space of well. Subsequently, plugging solution is subjected to treatment by acoustic field with frequency characteristic which is close to frequency of natural oscillation of casing string. Aforesaid acoustic field is created by source which is movable in casing string. Source generates single pressure pulses for possible creation of decaying oscillations in solution at initial pressure amplitude of 0.8-2.0 MPa. Treatment of solution is started at lowering of source of oscillations from well head towards bottom hole. In this case, time of reaching bottom hole by oscillation source is taken as equal to time of reducing pressure of plugging solution column down to reservoir pressure. During moving of oscillation source from bottom hole upwards, treatment of plugging solution is effected in two stages. At first stage, source moving speed is such that time of treating solution is near or equal to optimal time of acoustic treatment. This is maintained up to mark above which plugging solution acquires strength of structure which reduces column pressure down to reservoir pressure. At second stage, source moving speed is increased to value within which treating effect leads to complete destruction of plugging solution structure. Interval of source movement at this stage is determined by mark above which reduction of pressure of plugging solution column down to reservoir pressure is sufficient for return of oscillation source at same speed to initial mark for performing first step of next stage. After that, stages are repeated subsequently up to complete treatment within plugging solution location interval beyond string. EFFECT: higher efficiency. 4 dwg