METHOD AND APPARATUS FOR OPERATIONS IN UNDERGROUND SUBSEA OIL AND GAS WELLS

摘要

There has been explained a method and an apparatus for use in the advancing ofa rotating motorised downhole tool for carrying out operations in an oil/gaswell, especially in connection with the drilling and milling away ofcasing/casing sections in a well, which is to be abandoned and plugged bygrouting with a cement mixture, which will then reach the formation wallsurface where the casing/casing portion was milled away and removed. Therotating tool and its driving motor are indirectly suspended on coiled tubingat the free end thereof. As the platforms used for carrying out theseoperations are normally without rigs, it is advantageous to use coiled tubingto advance the tool/motor. However, coiled tubing cannot absorb a sufficienttorque from the tool/motor. Therefore the tool with its motor is connected toa carriage, a so-called "rolling anchor" (1) which absorb torques that occur,and is connected to the end of coiled tubing through a swivel coupling (sothat the torque will not be transmitted). Through the carriage (1) connectedthrough the swivel coupling to the coiled tubing, a pull on the coiled tubingprovides the tool and motor with advancing power for longitudinal movement, sothat the advancing of the tool takes place from below upwards, whereby it hasalso been taken into account, that to the coiled tubing there cannot besupplied any particularly great downward forces.