FIELD: oil and gas industry.
SUBSTANCE: device comprises a plaster in the form of smooth metal branch pipe with elastic sealing rings on the outside, and an expanding mandrel, made in form of double cone-transformer and consisting of head and tail cones-transforms, each of them is formed by spring-loaded cone-shaped segments located in grooves of a conical part of body for longitudinal movement. At that, the vertex of each cone-transformer body is directed to the side opposite to the working stroke of the expanding mandrel, which provides the smoothest expansion of the plaster. The maximum diameter of the head cone-transformer is less than the maximum diameter of the tail cone, which creates the appearance of a non-contact band of deformation of the plaster and reduces the axial force. The device is provided with a counter-return device for preventing backward stroke. A block of power reinforced collars is used as a piston driving the cone-shaped sectors. To control the geometry of the double cone-transformer, a deblocking mechanism is provided, by means of which the double cone-transformer is returned to the original diametric dimensions.
EFFECT: by reducing the deformation force of the plaster, emergency situations are prevented in case of jamming of the expansion mandrel in course of repair of casing and production strings, reliability and efficiency of the device increase.
3 cl, 5 dwg
