METHOD AND DEVICE FOR DESTRUCTION OF CEMENT STONE BEHIND CASING PIPE Russian patent published in 2024 - IPC E21B41/00 E02D9/00 E21B29/00 

FIELD: mining.

SUBSTANCE: group of inventions relates to construction of oil and gas wells and can be used for destruction of cement stone behind a casing string without its destruction, for subsequent extraction of the string. Method includes lowering into the well on tubing to the level of the destructible section of the spacer device, which includes adjustable jaws in the form of a part of the cylinder cut off by the plane, parallel to its longitudinal axis, flat surfaces facing each other, and hydraulic jack installed between them, filling of tubing with working fluid under pressure, providing activation of well spacer device, which creates a radial force on the casing of an oil or gas well in two diametrically opposite directions under the action of a jack perpendicular to the flat surfaces of the jaws in diametrically opposite directions with force specified within elastoplastic deformation of casing string without its destruction and with destruction of cement stone around casing pipe. Pressure is released in the tubing string, the spacer device is turned about its axis, and pressure is re-supplied to the tubing string. Further, the sequence of operations is repeated, the device is moved vertically along the well to the level of the undisturbed cement stone, the pressure of the working fluid in the tubing is increased and the cycle of operations is repeated. Outer part of the jaws corresponds to the inner part of the casing at the section of their contact and with the free surface of the tube between the jaws.

EFFECT: efficient destruction of cement stone, ruled out damage to casing pipe, reduced time of operations.

6 cl, 4 dwg