SU1599519A1 - Device for compensating for casing displacement - Google Patents

Abstract

The invention relates to the equipment of casing strings and can be used to fix oil and gas wells. The goal is to improve the quality of well casing by compensating for axial movements of the casing string during the waiting period for cement to harden. The device comprises a body 1, telescopically mounted relative to each other, with a guide stopper 2 and a locking body 3, and a centralizer 4 with operating elements 12. In the upper part, the central part has means 5 for communication with the casing string and is made in the form of two telescopically connected and mounted on bearing 7, parts 8 and 9. The nearby ends of parts 8 and 9 have cam projections 10 and 11 for interaction in the working position. The magnitude of the displacement is determined by the stiffness of the spring that is selected based on the magnitude of the compressive force. The reaction force in the lower part 9 of the centralizer 4, through its elements 12, is perceived by the well wall and is not transmitted to the casing. 1 hp f-ly, 2 ill.

Description

The invention relates to the equipment of casing strings and can be used to mount non-gas wells.

The purpose of the invention is to improve the quality of the mounting of the wells by compensating for the axial displacements of the column, the entire column, during the waiting period for the cement to harden,

Fig, 1 shows the device, GSH compensation movements of the casing, a general view; FIG. 2 is a section A-A of FIG. 1,

A device for compensating casing movements consists of a body 1, telescopically mounted relative to each other, with a plug 2 and a valve body 3, which is a spring-loaded non-return valve. The device includes a centralizer 4, in the upper part of which there is means 5, for example a thread, for communicating with the casing.

Case 1 is a supper relative: centralizer 4 is spring 6, centralizer 4 is made in the form of two telescopically connected and mounted on bearing 7 parts 8 and 9, upper and lower respectively: f The adjacent ends of the centralizer parts have cam projections 10 and 11, respectively, for interaction in the working position with the upper and lower parts of the body. The working elements 12 of the centralizer are arranged in a spiral on its lower part 9, the telescopic connections are sealed with sealing elements 13, the radial holes 14 serve to eliminate hydraulic resistance when the housing 1 is axially displaced relative to the centralizer.

The device operates as follows.

The device with the help of connecting thread 5 of the upper part 8 of the centralizer 4 is attached to the lower pipe of the casing string. During the descent of the column into the well, the working elements 12 of the centralizer 4, slamming into the wall, turn the latter, thus ensuring the centralizer is screwed into the wellbore. In this case, the upper part 8 of the center of the torus 4 interacts with its lower part 9 through an axial thrust bearing 7,

After the casing has been lowered to a predetermined depth, it is lifted up to the deposition of cam projections 10 and Po In this position, the centralizer is stationary relative to the axis of the casing.

Then, injecting and pushing the cement slurry into the annulus of the well, In the initial period of waiting for cement to harden on the closed valve body 3, the end of the device acts upward force, the size of which is determined by the hydrostatic pressure differential between the annular and internal spaces of the casing, forming density differences in cement slurry and squeezing fluid.

Under the action of this force, the body 1 moves upward, compressing the spring 6. The amount of movement is determined by the stiffness of the spring that is chosen, based on the value of the compression force. In this case, the reaction force at the bottom. 9, the centralizer 4, through its working elements 12, is perceived by the borehole wall and is not transmitted to the casing,

During the waiting period for cement hardening during hardening of the cement slurry, the hydrostatic pressure in the annulus decreases, and consequently, the pressure drop at the shut-off organ 3 of the device decreases and the force of the spring b is compressed, which causes the fixed centralizer 4 to move downwards, Casing- on the column, the centrifuge 4 remains stationary.

Thus, the use of this device improves the quality of the borehole by eliminating the fire movement of the casing in the waiting period for cement to harden, which allows for reliable adhesion of the cement stone to the casing and reduces the possibility of formation of fluid-conducting channels in the cemented area of the well. .

Claims (1)

Invention Formula I. Device for compensating casing movements, including a telescopic set   15995 relative to each other, the housing with a guide plug and a shut-off organ and a centralizer with working elements, having in the upper part a means of communicating with the casing string, is so tangible that, in order to improve the quality of the fastening of the armwork Due to the compensation of the axial movements of the casing string during the waiting period for cement hardening, the casing is spring-loaded relative to the centralizer. ten ten 196 and the latter is made in the form of two telescopically connected and bearing-mounted parts, with the adjacent ends of the centralizer parts having cam projections for interacting in the working position, V 2o The device according to any one of the preceding claims is that the working elements of the centralizer are arranged in a spiral on its lower part. 10 dl // Phys .2