INFLATABLE COLLAR AND DOWNHOLE METHOD FOR MOVING A COILED TUBING STRING

摘要

An elongated inflatable collar is securely attached to the exterior surface of a coiled tubing string before the tubing is lowered into the well for subsequent positioning at a predetermined subterranean location in the well casing. Upon inflation, the inflatable collar seals the annulus between the coiled tubing string and the well casing. A liquid injected from the surface creates sufficient hydraulic pressure on the upper surface of the inflated collar to advance the collar and the attached coiled tubing string and overcome frictional drag forces with the surrounding wall that caused the coiled tubing string to lock-up. The inflatable collar of the present invention can also be used to free a section of coiled tubing that is jammed in the formation due to buckling, by injecting a pressurized liquid into the wellbore downstream of the inflated collar to thereby apply a force to the downhole surface of the collar.