SU1629486A1 - Collar for stepped cementing of casings - Google Patents

Abstract

This invention relates to the mining industry and is used in two-stage casing cementing. The goal is to increase the reliability of the step-cemented coupling. The coupling includes a housing 1 with circulation holes 2 within which a movable sleeve 4 (PV 4) with circulation holes 5 and a mounting sleeve 3 are placed. On the latter there is a container

Description

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ner with compaction, into which, at the end of cementing, a cement plug comes in. Regarding the housing 1, the PV 4 is fixed by means of a fixing unit comprising a split ring 9, which interacts with the housing 1 with a locking sleeve. In the upper part of PV 4, a collet 14 is made of a chamber and radial holes 16. The sleeve in the upper part is made with an external end bevel that interacts with a counter bevel made on the inner surface of the split ring. In this case, the speed angle of the locking sleeve is greater than the friction angle between the material of the latter and the split ring 9. The coupling works

The invention relates to the mining industry, and more specifically to the oil and gas industry, and can be used in the step-by-step cementing of casing.

The purpose of the invention is to increase the reliability of the operation of the step-cementing casing coupling.

Fig. 1 shows the step cementing coupling in its initial position, section; 2 - the same, with the container inside the sleeve before cementing the second stage, in FIG. 3 - the fixing unit of the movable sleeve and the sealing element of the container; Fig. 4 shows a coupling for step-by-step cementing of casing strings after termination of cementing.

The coupling for stepwise cementing of casing strings includes a housing 1 with circulation holes 2, a landing sleeve 3, a movable sleeve 4 with circulation holes 5 installed inside the housing 1 with the possibility of axial movement relative to the housing 1, a cementing plug 6, a container 7 seconds sealing element 8. installed inside the housing 1 with the possibility of unpacking its sealing element 8 inside the movable sleeve 4, the fixing unit of the movable sleeve 4, made in the form of a split ring 9, interacting it with the housing 1, by means of a threaded connection 10 of the triangular profile, a lock sleeve 11 with seals 12 fixed

in the following way. After installation, the first stage is cemented at a predetermined interval using the upper separating plug. At the same time, the presence of the fixation unit prevents premature opening of the circulation holes of the coupling. In the process of washing the wells, the container is dropped into it and the second stage is cemented using a cement plug. After its entry into the container, the coupling is sealed, and the container together with the cementing plug and the landing sleeve 3 are lowered to the bottom of the well. 4 il.

using shear elements 13 inside the housing 1 with the possibility of axial movement. The movable sleeve 4 in the upper part is made with an external collar 14, an annular chamber 15 and bypass radial holes 16 placed in the lower part of the annular chamber 15. The locking sleeve 11 in the upper part is made with an external end bevel 17 that interacts with the response bevel 18. on the inner surface of the split ring 9, while the bevel angle of the locking sleeve 11 is greater than the friction angle between the material of the latter and the material of the split ring 9.

The container 7 is made with radial channels 19 and is installed with the possibility of unpacking its sealing element 8 above the radial bypass openings 16 of the movable sleeve 4. The seating sleeve 3 can be installed inside the housing 1 with a gap relative to the inner diameter of the casing to ensure free fall of the landing sleeve 3 on bottom hole. Threaded spring-crumbs 20 are installed in the windows of the movable sleeve 4. To the lower end of the movable sleeve 4, a seal assembly of the landing sleeve 3 including the cuff 21, the split washer 22 and the pressing sleeve 23 can be connected. The cuff 21 and the elements of the split washer 22 interact with the landing sleeve 3 and seal the gap of the landing sleeve 3 - the movable sleeve 4. To ensure the sealing of the internal cavity of the casing with the external space between the circulator openings 2 and 5, a differential sleeve 24 can be mounted fixed by shear elements 25.

The clutch works as follows.

In the position shown in Fig. 1, the sleeve is installed in the casing at a predetermined interval. After the end of the casing run, the first step- 5 plug 6 is cemented into the sealing container 7 using an upper plug (not shown).

When the cementing plug is seated on the stop ring, which is installed in the lower part of the casing, the shearing elements 25 are destroyed by the action of excess pressure on the differential sleeve 24, which hold the differential sleeve relative to the housing 1. The differential sleeve 24 moves upwards, and the circulation holes 2 open and 5, as evidenced by a sharp drop in casing pressure.

In the process of washing the wellbore from excess cement mortar of the first stage and the column, the container 7 is discharged, which under the action of its own weight and energy of the flow of the washing fluid moves along the casing string until it seats on the bushing 3 The axial channel of the coupling below the circulation holes closes, and the circulation of the washing liquid is carried out through the radial channels 19 in the container 7 and the circulation holes 2 and 5.

After keeping the technologically necessary time interval, the cement mortar of the second stage is pumped. After pumping

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The elongated element 8 remains pressed against the movable sleeve 4, since there is a continuous increase in pressure over the sealing element 8. Thus, after the cementing tube 6 enters the container 7, the axial channel of the coupling is sealed off, which leads to disruption of the hydraulic equilibrium between the cavities of the fixing unit.

The pressure in the column continues to increase until the shear elements 13 collapse. The sleeve 11 is displaced downwards, and the split ring 9 is disengaged from the housing 1. In this case the following occurs. As a result of the downward movement of the movable sleeve 4, the spring-loaded crackers 20 fall out into the internal cavity of the housing 1, the circulation openings 2 and 5 are sealed, and the extraction sleeve 23 lowers 1 the split washer 22 and the cuff 21 inwards. The bushing and container 7 with cementing plug 6, which have no connection with the column, freely fall to the bottom of the well. Sealing element 8 returns to its original position.

The use of a clutch makes it possible to increase the reliability of the stepwise cementing process by eliminating the possibility of premature closing.

The use of a clutch makes it possible to increase the reliability of the stepwise cementing process by eliminating the possibility of premature closing.

of the calculated volume of cement mortar, the cementing $ 0 coupling is lowered into the column when the treading plug of the first stage of the 6. plug is passed through it;

As the cement slurry is pushed into the annulus, pressure in the column increases. The force from the pressure drop above the coupling and under it through the landing sleeve 3, spring-loaded crackers 20, the movable sleeve 4 is transmitted to the different ring 9, which is located in 55

and also by increasing the reliability of closing the clutch.

Claims (1)

Invention Formula Coupling for step-by-step cementing of casing strings, including a pus with circulation holes, clinging to the housing 1. The locking sleeve 11 holds the split ring 9 in the initial position. At the time of termination of the forging of the cement mortar of the second stage, the cementing plug 6 enters the container 7, wherein the cups of the cementing plug 6 unclench the sealing element 8 until it touches the inner surface of the movable sleeve 4 above the radial bypass holes 16. After the final setting, the cement five 0 five 0 five The threaded element 8 remains pressed against the movable sleeve 4, as the pressure over the sealing element 8 continuously increases. Thus, after the cementing plug 6 enters the container 7, the axial channel of the coupling is sealed off, which leads to a violation of the hydraulic equilibrium between the cavities of the fixation unit. The pressure in the column continues to increase until the shear elements 13 are destroyed. The sleeve 11 is displaced downwards, and the split ring 9 is disengaged from the housing 1. In this case the following occurs. As a result of the downward movement of the movable sleeve 4, the spring-loaded crackers 20 fall out into the internal cavity of the housing 1, the circulation openings 2 and 5 are sealed, and the extraction sleeve 23 lowers 1 the split washer 22 and the cuff 21 inwards. The bushing sleeve and the container 7 with the cementing plug 6, which have no connection with the column, freely fall to the bottom of the well. Sealing element 8 returns to its original position. The use of a clutch makes it possible to increase the reliability of the stepwise cementing process by eliminating the possibility of premature closing. 0 clutch when passing through the centering plug of the first stage, and also by increasing the reliability of closing the clutch. Invention Formula Coupling for step-by-step cementing of casing strings including a core with circulation holes, landing sleeve, movable yn sleeve with circulating holes, installed in the housing with the possibility of axial movement, cementing plug, container with radial holes and sealing element, installed in the housing with the possibility of unpacking the snapshot element inside the moving sleeve, and fixing unit movable sleeve, made in the form of a split ring, interacting with the body by means of a threaded connection triangle-Hdro profile, which is designed to increase reliability in operation those, it is supplied with a lock sleeve with seals, fixed Compiled by N.Chepiga Editor V.Petrash Tehred L.Kravchuk in the housing with the possibility of axial movement, the movable sleeve in the upper part is made with an external shoulder, annular chamber and bypass radial holes located in the lower part of the annular chamber, the lock sleeve in the upper part is made with an external end bevel, which interacts with the response bevel made on the inner surface of the split ring, while the bevel angle of the locking sleeve is greater than the friction angle between the material of the latter and the split ring, and the container is installed with the possibility of unpacking it sealing element above the bypass radial holes of the movable sleeve 1 14 4 Proofreader N. Revska