METHOD FOR CASING PIPE SEALING AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2014 - IPC E21B33/13 E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: metal sheet - a cover plate of rectangular shape - is made with thickness of 2-3 mm and more of smart alloy, for example, of nitinol, rolled in a roll in cryostat at temperature of 80°C below zero and less, placed into an elastic tubular sleeve with length not less than the cover plate height and installed in a device where temperature is maintained below the temperature of material return to its initial shape, by means of carbon dioxide ice; then the device with cover plate is run-in to the point of the pipe sealing failure, the cover plate is removed from the device body and it is warmed up by liquid in the well, at that action of thermoelasticity starts and the cover plate intends to return into its initial flat state, but casing pipes prevent it and the cover plate is pressed to their inner surface through the elastic packing thus ensuring good sealing along the whole surface perimeter. The device for casing pipe sealing consists of a cylindrical body (1) with the upper butt end closed by the flat cover, in the latter there is a central opening and a short pipe (4) with thread at its free end is welded to be connected to the pipe string (5) before running-in, while the lower butt end of the body is closed by a circular bottom (13) with ball locks (12) in their lateral surface to maintain the bottom in the state connected to the body, and at their inner surface there is a lower cable anchor assembly (10) while the other end is fixed by an upper cable anchor assembly (6) placed at the lower butt end of the short pipe, at that the cable (8) length shall be equal to at least two heights of the cover plate; inner surface of the body and bottom is covered by a layer of heat insulating material (2) so that the cover plate could not be heated up during a short period of running-in; between inner volume of the short pipe and the body there is a connection in the form of openings for the purpose of liquid passing through them under pressure and the cover plate roll is placed inside the body, the latter is turned upside down and free space inside it is filled with carbon dioxide ice (16), then the bottom is installed and the body is turned into the initial position. The invention allows reliable and long-term operation of the sealed casing pipes.

EFFECT: eliminating sealing failure of the casing pipe with different types of damages.

2 cl, 3 dwg