SU1665022A1 - Method for well casing and cementing - Google Patents

Abstract

The invention relates to the construction of oil and gas wells. The goal is to reduce the amount of force applied to stretching the compressed section of the casing string. The well is washed, cemented and stretched to the compressed area of the casing at the wellhead. The compressed area of the casing is subjected to an additional tensile force within the area itself by injecting fluid into the column under excessive pressure with a density equal to or greater than the density used in flushing the drilling fluid. Then, at the same time as the pressure is released, the relocated casing shoe is rigidly fixed in the well. The device for carrying out the method comprises a housing with radial washing windows, covered with a movable sleeve with a saddle under a casting ball fixed in the housing on the shear elements, and a detachment mechanism including folding spring-loaded legs. In the upper part of the movable sleeve on the shear elements a retaining ring is fastened. The body is made with a stop groove under a retaining ring installed relative to the latter with an axial clearance equal to the largest dimension of the cross section of the shear elements fixing the sleeve in the body. At the moment of opening of the washing windows, the internal pressure decreases, and the folding legs abutting the walls of the well, become wedged in the rock with a regenerating compressive force. Occurring after squeezing the stamping solution on the non-return valve, the compressive load from the action of the pressure drop is perceived by the fixed device. 1 hp ff, 2 ill.

Description

The invention relates to the construction of oil and gas wells and can be used to fix wells to improve the quality and reliability of the lining.

The purpose of the invention is to reduce the magnitude of the force applied to stretching the compressed section of the casing.

Figure 1 shows the device, a general view; figure 2 - section aa in figure 1.

Stretching of the compressed section of the casing can be carried out in the following during the following periods of well installation: prior to cementing, when pumping cement slurry into the pipe string, at the end of punching

cement slurry into the annulus (at the time of receipt of stob).

The device consists of a housing 1 with flushing channels and a guide nozzle 2, a movable sleeve 3 with o-rings 4 fixed by shear elements - bolts 5, an anvil ring 6 fixed to the upper part of the movable sleeve 3 shear elements - calibration bolts 7, the release unit, including hinged paws 8, springs 9, axles 10 and support shoes 11. Hinged paws 8 are installed in slots of housing 1 and are held in transport position with shear bolts 5. For the course of the complex, bushings 3 and the stop ring b Motrya annular gap and equal to the largest cross-sectional dimension of the shear elements securing the sleeve in the housing.

The method with the device is carried out as follows.

A device is fixed to the first casing pipe in its lower part, and a check valve — a flapper (not shown) is installed in the upper part, passing freely through the ball. The casing is lowered to the intended depth, the well is flushed, the ball 12 is thrown with pumping of the drilling fluid before it is seated in the sleeve 3. After the ball 12 of the flushing channel is blocked, an internal pressure less than that calculated for moving the shoe at which the bolts 5 are cut is created , the sleeve 3 moves downward until the bottom end of the stop ring 6 is in contact with the ledge of the housing 1, and during this period the hinge legs under the action of the springs 9 are ejected into the working position, i.e. prior to their contact with the borehole wall. The stroke length of the sleeve 3 is chosen so that the paws of the device come into contact with the borehole wall before opening the flushing windows. Then, the calculated internal pressure is created, at which the shoe moves to the required amount with the removal of the compressive force in the casing string, the calibration bolts 7 are cut, the sleeve 3 is further moved downwards and the flushing windows are opened. At the time of opening of the flushing windows, the internal pressure decreases, and the folding legs, abutting against the walls of the well, are wedged in the rock with a regenerating compressive force. Thereafter

Cementing is carried out in the usual way.

The compressive load arising from the pressure of the cement slurry on the non-return valve due to the pressure drop due to the difference in density of fluids outside and inside the column is perceived by the fixed device.

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Claims (1)

1. A method of securing a well, including its washing, cementing and stretching the compressed section of the casing with a wellhead, characterized in that, in order to reduce the magnitude of the tensile stress on the compressed section of the casing, the latter is subjected to an additional tensile force in limits of the plot itself by pumping a fluid under pressure in the column with a density equal to or greater than the density used for flushing the drilling fluid, and then simultaneously with removal, the pressure is rigidly fixed in the well displaced casing shoe. 2, A device for fastening a well, consisting of a body with radial flushing windows blocked by a movable sleeve with a saddle for a waste ball fixed in the body on the shear elements and a detachment mechanism including radially folding spring-loaded legs, characterized by the fact that, in order to reduce the magnitude of the tensile force on the compressed section of the casing, it is provided with a retaining ring fixed in the upper part of the movable sleeve on the shear elements, and the casing is made with a stop groove under the retaining ring installed relative to the latter with an axial clearance equal to the largest measuring the cross section of the shear elements fixing the sleeve in the housing. but 1 Editor N. Yatsola Compiled by V. Nikulin Tehred M. Morgental Figg Proofreader M.Kucher va