| 摘要 |
FIELD: oil and gas industry, particularly well operation. ^ SUBSTANCE: method of air-tightness determination involves measuring background pressure in tubing-casing annulus; providing gas-dynamic connection at well head between hole annuity and tubing-casing annulus at moment of background pressure stabilization in tubing-casing annulus; increasing background pressure in tubing-casing annulus in several stages to reach maximal possible test pressure , wherein the pressure increase is 1 MPa for each stage, along with performing time-delay at each stage to relax and stabilize tubing-casing annulus pressure. If tubing-casing annulus pressure is time-stabilized at last stage well head conductor or extension pipe part air-tightness is assumed to be perfect. If tubing-casing annulus pressure is reduced at one stage after relaxation operation the pressure value is recorded in relaxation termination period. Then time-delay is carried out until pressure stabilization in tubing-casing annulus, time-delay duration and pressure values are recorded and compared with background pressure value. If tubing-casing annulus pressure exceeds background pressure one may make a decision that the well may be operated under above tubing-casing annulus pressure, which does not exceed recorded stabilization pressure value. If tubing-casing annulus pressure is equal to background pressure one may make a decision that well head conductor or extension pipe part has not sufficient air-tightness. Then gas is discharged from tubing-casing annulus to obtain value of 0.9Pst with taking into consideration time and volume of gas to be discharged and with time delay, which provides pressure release and stabilization in tubing-casing annulus. The last values are recorded and residual gas is released from tubing-casing annulus. Then constant inflowing gas yield is measured and tubing-casing annulus gas leakage value is determined from a given relation. If gas leakage value is lesser than 70 m3/day one may make a decision that well may be operated along with tubing-casing annulus gas bleeding for gas combustion in flare when pressure value reaches value equal to background pressure value. If gas leakage value is greater than 70 m3/day one may make a decision that well operation must be stopped to perform well isolation works. ^ EFFECT: increased information validity. ^ 3 dwg, 2 ex |
