METHOD FOR CASING PIPE REPAIR Russian patent published in 2006 - IPC E21B29/10 

FIELD: oil production industry, particularly to recover casing pipe air-tightness.

SUBSTANCE: device comprises connection pipe, expanding cone formed to press the connection pipe to casing pipe wall and having diameter at base thereof less than inner connection pipe diameter in its operative position. The connection pipe is fixedly secured to pipe string from top thereof. The pipe string includes fixed additional connection pipes having the same structure as above connection pipe. Pipe string has inner diameter enough for expanding cone passage though the pipe string. All connection pipes from upper and lower ends are provided with upper and lower expanded parts. The lower expanded part of the connection pipe is adapted for circulation valve receiving. The circulation valve admits flow in top-bottom direction and has body connected to the connection pipe by shear screws in air-tight manner. The expanding cone is inserted in upper expanded part of upper additional connection pipe and has orifice and seat for valve droppable from well head. Collar, which is self-sealed in top-bottom direction, is fixedly secured to expanding cone. All connection pipes between upper and lower expanded parts are provided with longitudinal corrugations having greater plasticity in comparison with that of pipe string and elastic envelopes are arranged on outer surfaces thereof. Expanding body and circulation valve body are formed of drillable materials.

EFFECT: simplified structure and increased reliability.

3 dwg