RU2782908C1 - Device for running and cementing a liner in a well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, and in particular to a device for running and cementing a liner in a well. The device contains a coupling for connecting the device to the transport pipe string, a body, a liner, a shoe with a valve assembly, a suspended cementing plug with a central passage channel, a landing seat for a plug dropped from the wellhead, a landing cone made at the lower end for landing is installed on the shear elements into the seat of the stop ring. At the upper end of the housing, grooves are made for external protrusions made on the surface of the coupling. The housing is made in the form of an expandable branch pipe, provided with a constriction in the upper part and a sealing element outside the constriction. The coupling is connected to the body by means of a release assembly made on the coupling below the outer protrusions and consisting of a groove and an expanding cone placed in the body in such a way that when the pressure in the well rises above the “stop” pressure, the coupling is pushed out of the body with simultaneous expansion by its expanding cone. The coupling from below in the central channel is equipped with a groove, in which a suspended cementing plug is installed on the shear elements, blocking the radial holes communicating the central channel of the coupling and the cylindrical selection of the coupling located inside the sub connecting the body and the liner. The sealing element on the outside of the body constriction is made of such a thickness that after the expansion of the body with an expanding cone, the sealing element is compressed by 5-80% to the well walls to seal the device in the well.

EFFECT: providing an easy-to-manufacture and reliable device for running and cementing a liner in a well with rotation, as well as the ability to install a liner with sealing, including in horizontal wells.

1 cl, 2 dwg

Description

The invention relates to the oil and gas industry, and in particular to methods and devices for cementing a liner in an open and cased wellbore.

A device for cementing a liner in a well is known (patent RU No. 134574, IPC E21B 33/13, E21B 33/14, publ. , shank, valve assembly in the form of a spring-loaded check valve and shoe. Radial holes are made in the wall of the mounting sleeve, in which diaphragms destructible under hydraulic pressure are installed, while it is attached to the body on the left-hand thread, inside the body, on sheared screws, a suspension cementing plug is installed in the form of a block of elastic conical cuffs with a core with a central passage channel and a landing a saddle in the upper part under the cementing plug discharged from the wellhead and a landing cone made on the lower thrust ring of the conical collar block for seating the stop ring installed in the joint between the lower end of the liner and the upper end of the valve assembly adapter, in the coupling connecting them.

The disadvantages of this device are:

- the impossibility of rotation of the liner during its descent into a given interval of the well and in the process of cementing, which makes it difficult to pass in the zone of curvature of the wellbore and slurry pads, and also does not provide high-quality replacement of the cement slurry in the annulus;

- disconnection of the transport string from the liner is carried out by means of a left-hand thread, which makes it problematic or even impossible to disconnect with a short liner length and in a horizontal wellbore.

The closest in technical essence to the claimed is a method of cementing a liner in a well and a device for its implementation, (patent RU No. 2595122, IPC E21V 33/14, publ. device to the pipe string, a body, a liner, a shoe with a valve assembly, a hole with a diaphragm that is destroyed under hydraulic pressure, while the coupling is attached to the body by a release device, a suspension cementing plug is installed inside the body on shear screws in the form of a block of elastic conical cuffs with a core with a central passage channel and a landing seat for a plug dropped from the wellhead and a landing cone made on the lower thrust ring of the conical collar block for landing in the stop ring seat. A hole with a diaphragm is made in the body below the sleeve, below which an annular constriction is made in the body in the area of fixation with shear screws of the suspension plug, and the diameter of the constriction is 2-6 mm less than the inner diameter of the shank, the drop plug is made in the form of a technological ball with a density close to the density grouting slurry, while at the upper end of the liner body there are grooves for external protrusions made on the surface of the coupling, and the release mechanism is made in the form of balls inserted into the radial holes of the coupling and interacting from the outside with the inner recess of the liner body, and from the inside supported by a saddle under the throw ball , wherein the minimum inner diameter of the seat is greater than the diameter of the technological ball, and the seat is provided above the radial holes with an outer cylindrical groove, fixed by shear elements in the upper position and made with the possibility of limited downward movement after the destruction of the shear elements until the balls interact with groove and exit of the balls from interaction with the annular selection of the body, while the valve assembly is made in the form of a sleeve with an upper blind axial channel in which the stop ring is placed, and radial channels connected with the axial channel below the stop ring, communicating the space of the shoe above and below bushing, wherein the bushing is fixed in the shoe with shear screws in the upper position and is made with the possibility of limited downward movement after the destruction of the shear screws with hermetic overlap of the shoe cavity and fixation by the locking mechanism in the lower position, the locking mechanism is made in the form of a spring ring inserted into the annular recess from the outside sleeve and made with the possibility of interaction with the inner annular selection inside the shoe in the lower position of the sleeve.

The disadvantages of this device are:

- after running the liner and cementing it, there is no sealing of the upper part of the liner in the well due to the cement leaving the loss zone and exposing the body and the upper part of the liner;

- the complexity of manufacturing due to the large number of mating parts.

The technical task is to create a device for running and cementing a liner in a well with rotation, easy to manufacture and reliable in operation, which allows the liner to be installed, including in horizontal wells, with sealing in the well.

The technical problem is solved by a device for running and cementing the liner in the well, containing a coupling for connecting the device to the transport string of pipes, a body, a liner, a shoe with a valve assembly, a suspended cementing plug with a central flow channel, a landing saddle for being dropped from the wellhead is installed on the shear elements plug, with a landing cone made at the lower end for landing in the seat of the stop ring, on the upper end of the shank body, grooves are made for external protrusions made on the surface of the coupling.

What is new is that the housing is made in the form of an expandable branch pipe, equipped with a narrowing in the upper part and a sealing element outside the narrowing, while the coupling is attached to the housing using a release assembly made on the coupling below the outer projections and consisting of a groove and an expanding cone placed in the casing in such a way that when the pressure in the well rises above the “stop” pressure, the sleeve is pushed out of the casing with its simultaneous expansion with an expanding cone; connecting the central channel of the coupling and the cylindrical selection of the coupling located inside the sub connecting the body and the liner, and the sealing element outside the narrowing of the body is made of such a thickness that after the expansion of the body with an expanding cone, the sealing element is compressed by 5-80% to the walls wells for sealing the device in the well.

In FIG. 1 shows a device for running and cementing a liner in the well in an assembled form before running into the well.

In FIG. 2 shows the structural elements of the device after all operations for cementing and detaching the transport pipes.

The device for lowering and cementing the liner in the well contains a sleeve 1 (Fig. 1) for connecting the device to the transport string of pipes (not shown in the Fig.), a body 2, a liner 3, a shoe 4 with a valve assembly 5. a cementing plug 7 with a central passage channel 8, a landing saddle 9 for a plug 10 dropped from the wellhead (Fig. 2). Suspended cementing plug 7 is equipped with a landing cone 11, made at the lower end for landing in the saddle 12 of the stop ring 13. On the upper end 14 of the housing 2, grooves 15 are made for the outer protrusions 16, made on the surface of the coupling 1.

Housing 2 is made in the form of an expandable branch pipe, equipped with a constriction 17 in the upper part and a sealing element 18 outside the constriction 17. The coupling 1 is attached to the housing 2 by means of an uncoupling assembly made on the coupling 1 below the outer protrusions 16. The uncoupling assembly consists of a groove 19 and expanding cone 20, made on the sleeve and placed in the housing 2 in such a way that when the pressure in the well rises above the "stop" pressure, the sleeve 1 is pushed out of the housing 2 while expanding it with an expanding cone 20. Also, the sleeve 1 from below in the central channel 21 is provided with a groove 22, in which a suspended cementing plug 7 is installed on the shear elements 6, covering the radial holes 23 communicating the central channel 21 of the coupling 1 and the cylindrical sample 24 placed inside the sub 25 connecting the body 2 and the liner 3. The sealing element 18 is outside the constriction 17 of the body 2 made of such a thickness that after the expansion of the body 2 with an expanding cone 20 o The sealing element 18 was compressed by 5-80% to the borehole walls (Fig. not shown) to seal the device in the well.

The device works as follows.

The liner 3 with the shoe 4 through the coupling 1 (Fig. 1) is attached to the lower end of the transport pipe string (not shown in Fig.) and lowered into the well to a predetermined depth. The sleeve 1 is connected to the liner 3 with the possibility of synchronous rotation due to the interaction of the outer protrusions 16 of the sleeve 1 with the grooves 15 made on the end face 14 of the body 2. The liner 3 can be rotated, as during the descent into the well, to overcome the resistance of the slurry pads, regardless of length, complexity and the direction of the wellbore, and during the cementing operation - for better replacement of the annulus with cement mortar.

Further, according to the program of work, buffer fluid is pumped and then the estimated volume of cement slurry is pumped. In order to exclude the effect of hydraulic pressure on the uncoupling unit, the radial holes 23 communicating the central channel 21 of the coupling 1 and the cylindrical sample 24 located inside the sub 25 connecting the body 2 and the liner 3 are blocked by a suspended cementing plug 7. After that, from the wellhead to the transport string drop plug 10 (Fig. 2). It reaches the suspended cementing plug 7 and, getting into the landing saddle 9, is fixed in it and blocks the passage channel 8. By further increasing the hydraulic pressure, the elements 6 are sheared (Fig. 1) and the suspended cementing plug 7, together with the plug 10, exits the groove 22 and starts moving down. In this case, the grouting slurry is displaced into the annulus, passing through the holes of the shoe 4. Upon reaching the seat 12 of the stop ring 13, the plug 7 is fixed in it, hermetically blocking the internal space of the liner 3 from the annulus, and a pressure jump occurs (“stop” pressure) . Thus, we receive a signal about the completion of the cementing process. The valve assembly 5 then closes and prevents cement from the annulus from getting back into the liner 3.

Then continue to increase the hydraulic pressure inside the shank 3 to the design. In this case, the clutch 1 (Fig. 1) is pushed out of the housing 2 with its simultaneous expansion by the cone 20 of the clutch 1. After the clutch 1 with the cone 20 and the groove 22 completely leaves the housing 2, the narrowing 17 (Fig. by means of a sealing element 18 is tightly pressed against the walls of the production casing (not shown in Fig. 1, 2). Thus, the “head” of the liner 3 becomes airtight even if the cement slurry partially escapes into the absorption zone, if it exists.

Then the transport string with the sleeve 1 located at its lower end is lifted to the estimated distance from the liner 3 and the residual cement slurry is cut off above the "head" of the liner 3 with the flushing liquid. After that, the transport string is lifted to the wellhead, and the liner 3 is left for the operation of cement hardening.

The proposed device is simple to manufacture and reliable in operation, allows you to install liners with sealing, including in horizontal wells.

Claims (1)

A device for lowering and cementing a liner in a well, comprising a sleeve for connecting the device to a transport string of pipes, a body, a liner, a shoe with a valve assembly, a hanging cementing plug with a central flow channel, a landing saddle for a plug dropped from the wellhead, a landing a cone made at the lower end for fitting into the seat of the stop ring, on the upper end of the shank body there are grooves for external protrusions made on the surface of the coupling, characterized in that the body is made in the form of an expandable branch pipe, equipped with a narrowing in the upper part and a sealing element on the outside narrowing, while the sleeve is attached to the body by means of a release assembly, made on the sleeve below the outer projections and consisting of a groove and an expanding cone, placed in the body in such a way that when the pressure in the well rises above the “stop” pressure, the sleeve is pushed out of the body with simultaneous expansion In addition to its expanding cone, the sleeve is also equipped with a groove from below in the central channel, in which a suspended cementing plug is installed on the shear elements, blocking the radial holes communicating the central channel of the sleeve and the cylindrical selection of the sleeve located inside the sub connecting the body and the liner, and the sealing element is outside the narrowing of the body is made of such a thickness that after the expansion of the body with an expanding cone, the sealing element is compressed by 5-80% to the walls of the well to seal the device in the well.

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