RU2584428C1 - Device for stage cementing of casing strings - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and is intended for stage cementing of casing strings in wells. Device includes housing with holes. Bushings with shear elements are connected to housing. There is trunk in axial channel of housing with formation of annular chamber, hydraulically connected with axial channel of trunk. Trunk is made with stepped bore. It incorporates mounting bushing with inner circular ledge, pressed with nut, and sleeve with upper collet with lobes. Their heads are arranged inside the circular ledge of mounting bushing. There is lower collet with lobes and barrel with valve seat in axial channel. Barrel is installed in axial channel of sleeve to rest on circular ledge of lower collet lobes. There is stepped shutter with external circular ledge, equipped with seat installed inside the barrel to interact with heads of upper collet lobes. In annular chamber there is seating mechanism in form of annular bushing and hollow rod. At rod lower end there is expanding cone with retaining ring. Trunk is equipped with nut and extrusive washer, and package of sealing cuffs. In barrel there are bypass holes, aligned with holes in sleeve body and circulation holes in trunk. Annular chamber is hydraulically connected through radial holes in housing with annular space of well.

EFFECT: technical result is possibility to release device channel without drilling.

1 cl, 3 dwg

Description

The invention relates to the oil and gas industry and is intended for stepwise cementing of casing strings in wells.

A device for well completion is known (see AS No. 1186786, M., class. E21B 33/14, publ. 23.10.85, bull. No. 39).

The device is included in the production string and consists of a filter in the axial channel of which is placed a cylindrical pipe. The annular gap between them is blocked by the packer. At the bottom of the cylindrical nozzle, a shear diaphragm is installed with an arrangement below the filter openings. A drillable diaphragm is installed above the filter, above which a circulation sleeve in the form of a hole is placed.

The device descends into the well on the casing string. After cementing the casing, the upper diaphragm is drilled, with the drilling fluid replaced with a lighter working fluid. Tubing with a production packer is lowered into the well.

A pressure rise is carried out with a cut of the pins connecting the diaphragm to the cylindrical nozzle, and its discharge down into the deaf filter shoe.

They carry out activities for the development and commissioning of the well.

The disadvantages of the design of the device include:

- the presence of a circulation sleeve, depicted as a hole in the body of the production string above the diaphragm, gives reason to consider the existence of a hydraulic connection between the axial channel of the production string and the axial channel of the filter, which during cementing will invariably lead to grouting mortar both in the filter cavity and in the productive layer;

- the need to drill a diaphragm will negatively affect the quality of cementation, with a decrease in the sealing properties of cement stone.

A device is known for cementing production casing with a filter (see AS No. 1654544, M., class E21B 33/14, publ. 07.06.91, bull. No. 21).

The device is installed in the production casing, in the lower part of which is fixed a filter with a sealing unit - a packer.

A cementing device is installed over the packer using an adapter; a shoe is placed on the lower end of the filter.

The cementing device consists of a housing, an additional sleeve in the axial channel and a sleeve with a blind bottom. Windows are made in the case, which are blocked in the initial position by the body of the additional sleeve, in which the side windows are also made. The additional sleeve is connected to the housing by shear pins. In the initial position, the windows of the additional sleeve are combined with the side windows of the housing and the side windows of the sleeve with a blank bottom. The outer diameter of the sleeve is adopted less than the inner diameter of the housing and filter. The additional sleeve and the bush with a blind bottom are connected to each other by shear elements.

The operation of the device.

The arrangement of production casing devices is carried out in the usual way. A packer may be used as the sealing assembly.

In the process of lowering the casing string, it is freely filled with formation fluid.

After lowering the casing string, the well is flushed with the annulus sealing by the packer.

Buffer fluid and cement slurry are pumped into the casing. After that, an elastic plug is fed into the column and pushed with drilling fluid until it contacts the upper end of the sleeve with a dead bottom. Then, elastically deforming, the elastic plug enters the axial channel of the sleeve with a dead bottom. With the calculated pressure difference, the pins are cut off and both bushings - additional and with a blank bottom - are lowered down to the ledge inside the axial channel of the housing. The side windows in the body of the case are hermetically sealed. At the calculated pressure drop, which is greater than the previous one, the pins are cut off, which contributes to the exit of the sleeve with a dead bottom from the axial channel of the additional sleeve and the fall into the filter, which remains open for the formation fluid to enter the cavity of the pipe string.

If necessary, deepen the bore holes of the sleeve can be drilled together with an elastic plug.

The disadvantages of the design of the device:

- unreliability of the sequence of operation;

- destruction of shear elements connecting the additional sleeve with the housing and the sleeve with a deaf.

If the destruction of the shear element, which connects the sleeve with a blank bottom and the additional sleeve, is carried out earlier than the destruction of the shear element connecting the additional sleeve to the body, the device will not perform its functions, the essence of which is to isolate the annular space from the in-pipe, with the prevention of the return of cement solution back.

Known valve device for two-stage cementing of the casing (see AS No. 746085, M., CL EV 33/14, publ. 07.07.80, bull. No. 25), adopted by the authors for the prototype.

The device consists of a housing with radial openings, bypass channels, a lower sleeve with a support collar and an internal protrusion, under which an annular pocket is made. Side holes are made in the body of the lower sleeve and it is connected by shear pins to the housing. In the axial channel of the lower sleeve there is a composite step sleeve with split springs with petals on which a rubber nozzle is mounted. The petals themselves have supporting protrusions with which they enter the inner bore in the protrusion of the lower sleeve. The stepped sleeve forms an annular chamber with the body of the lower sleeve, connected by a radial hole with the axial channel of the stepped sleeve under the petals. Above the lower sleeve in the axial channel of the housing there is an upper sleeve equipped with a spring clip and connected with the housing by a shear element. In the axial channel of the upper sleeve, a sleeve-saddle is installed, connected with it by a shear element.

In the body of the body, under the upper sleeve, a groove is made to interact with the latch.

The housing of the device is connected with an inflatable packer, the cavity of which is connected by a hydraulic channel to the axial channel of the housing. To control the device, a ball and a cork plug are used.

The operation of the device.

After the first stage of cementing is completed, a ball is dropped into the well, landing on a rubber nozzle covering the petals of an additional sleeve. With increasing pressure, the pins are cut off connecting the lower sleeve with the housing, and it moves down to align its side holes with the hydraulic channel for landing the inflatable packer. After that, the pressure is increased to cut the screws on the lower sleeve with its movement down to the stop by the stepped sleeve into the annular protrusion of the housing, with the hydraulic channel blocked to the inflatable packer and the radial openings for supplying grouting mortar into the annular space of the well. Cement mortar is supplied to the device through a drill pipe string with a push-through dividing plug, which is brought to the inside of the sleeve-saddle, with a cut of the studs connecting the upper sleeve to the body.

The upper sleeve with the sleeve-saddle and plug move down, pushing the lower sleeve all the way. After the sealing ring passes through the radial hole in the body of the step sleeve, with increasing pressure inside the annular chamber, the step sleeve moves upward, with the petals of the additional sleeve expanding in the radial direction and their location in the groove of the lower sleeve. In this case, the ball is thrown down. The upper sleeve hermetically seals the radial holes in the housing. With increasing pressure, the pins cut off connecting the sleeve-saddle with the upper sleeve, and the sleeve-saddle with the separation plug is thrown down.

The disadvantages of the design of the device include:

- the complexity of the design and technological methods for controlling the nodes of the device;

- it is difficult to assemble the parts of the device, for example, the installation of a stepped sleeve, with the passage of the petals with a rubber nozzle through the narrowing. In this case, the petals must be compressed, which is more than problematic;

- after cutting the pins connecting the upper sleeve with the housing, it will suddenly move downward, with the dubious entrance of the latch into the housing bore;

- the operability of the device at the time of the seal, in the body of the step sleeve, the annular chamber is closed, and due to the movement of the lower sleeve down, the step sleeve will move along with the ball up. But this upward movement will take place until the ball is in contact with the body of the rubber nozzle on the petals of the stepped sleeve. Premature opening of the petals will lead to the discharge of the ball and pressure both in the axial channel of the lower sleeve and in the annular chamber. This indicates an unreliable response of the device nodes. This position of the petals on the stepped sleeve will lead to a partial overlap of the cross section of the axial channel and may be an obstacle to the further passage down the sleeve-saddle with the cork stopper.

The technical result that can be obtained by implementing the invention is as follows:

- the ability to provide hydraulic communication of the axial channel of the drill pipe string with the annular space blocked by the packer;

- the ability to isolate the annulus from the annulus after cementing;

- the possibility of releasing the axial channel of the device from the glass with a stepped curtain without drilling.

The technical result is achieved by the fact that the device for stepwise cementing of casing strings consists of a housing with holes, shear sleeves, shear elements connected to it, seat seats in the axial channel, a packer sealing assembly, a landing mechanism, a barrel with a stepped axial channel introduced into the axial channel housing, with the formation of an annular chamber, hydraulically connected with the axial bore of the barrel, in which the landing sleeve with an inner annular protrusion placed by a nut is placed. Below the barrel is a sleeve with an upper collet with petals, the heads of which are located inside the annular protrusion of the landing sleeve, and a lower collet, the petals of which are equipped with an internal annular protrusion. The landing valve is made in the form of a cup with a seat in the axial channel placed in the axial channel of the sleeve with the possibility of support on the annular protrusion of the lower collet petals, and a step curtain with an external annular protrusion equipped with a landing saddle, which is installed inside the cup, with the possibility of interaction with the petal heads upper collet and associated shear element. In the annular chamber there is a landing mechanism in the form of an annular sleeve and a hollow rod, at the lower end of which there is an expandable cone with a restrictive ring, and the barrel is equipped with a nut with an extrusion washer and a package of sealing cuffs. Bypass holes are made in the glass, combined with holes in the body of the sleeve and circulation holes in the barrel, with an annular chamber hydraulically connected by radial holes in the casing with the annulus of the well.

The design of the device for cementing wells is shown in section in the figures, where:

- in FIG. 1 - the device in the context, in the initial position of the parts, included in the casing;

- in FIG. 2 - sectional device in the isolation position of the annulus of the packer and the formation of hydraulic communication of the axial channel of the casing pipe with the annulus;

- in FIG. 3 - the device in the context of isolation of the annular space from the annular after the sale of cement slurry and the release of the axial channel from the landing valve.

A device for stepwise cementing of casing strings in a well consists of a housing 1 with an adapter 2 at the upper end for connection with a casing string. A barrel 3 is fixed on the internal thread of the adapter 2, forming an annular chamber 4 with the housing 1, in which a sleeve 5 is placed, connected by a shear element 6 with the barrel 3 and the housing 1. Below the location of the sleeve 5, a hole 7 is made in the body of the housing 1 for annular hydraulic communication chambers 4 with annulus. An annular sleeve 8 and a hollow rod 9 with an expanding cone 10 at the lower end, made with an inner protrusion covering the barrel 3 with the formation of a movable joint, are placed in the annular chamber 4. At the lower end of the barrel 3, a pack of sealing collars 11 of the packer is installed, pressed against the expansion cone 10 by a nut 12 provided with an extrusion washer 13. A restriction ring 14 is placed on the outer surface of the expansion cone 10. The annular sleeve 8 and the hollow stem 9 are connected to the housing 1 by shear elements 15 and 16, respectively.

Inside the barrel 3, a thread 17 and a stepped groove 18 are made, in which the landing sleeve 19 with the inner annular protrusion 20 is mounted, fixed with a nut 21. Below, in the axial channel of the barrel 3, there is a sleeve 22 with an upper collet 23, the petals of which are placed in the bore of the landing sleeve 19 based on the protrusion 20, and the lower collet 24, the head 25 of the petals of which are placed in the barrel 3 under the stepped groove, with its external surface in contact with the inner wall of the barrel 3. In the body of the barrel 3 there are circulation openings 26 combined with holes 27 in the body of the sleeve 22, in the axial channel of which a landing valve is installed, consisting of a cup 28, which is supported by an end 29 on an inner protrusion 30 formed on the heads 25 of the petals of the lower collet 24. Inside the cup 28, a seat 31 is made for mounting the ball 32. In the axial a channel of the cup 28 has a stepped shutter 33, with an outer annular protrusion 34 covered by the petals of the upper collet 23. A landing saddle 35 is made inside the outer annular protrusion 34. A stepped shutter 33 is connected to the cup 28 with a shear element 36.

In the body of the glass 28, bypass holes 37 are made, located at the level of the circulation holes 26 in the barrel 3.

In the axial channel 38 of the barrel 3, below the location of the heads 25 of the petals of the lower collet 24, a technological groove 39 is made with the possibility of placing the heads 25 of the petals of the lower collet 24 in it when the sleeve 22 is in its lowest position.

A step 40 is made on the outer surface of the barrel 3 below the location of the technological groove 39, in which the expanding cone 10 abuts, coming into contact with its conical surface 41 with a package of sealing cuffs 11. At the lower end of the barrel 3, a connecting thread 42 is made for connection with pipes of the lower section casing string or filter (not shown in the figure).

The annular chamber 4 is constantly hydraulically connected by radial holes 43 in the housing 1 with the annular space.

The annular gaps between the mating parts are insulated with o-rings.

The operation of the device.

The device is included in the composition of the casing string between the sections of the first and second stages of cementing or between the casing string of the pipe and the filter part of the string, not intended for cementing.

The casing is lowered to a predetermined depth.

In this case, as the layout is lowered, the column is freely filled through the axial channel of the barrel 3 of the device with borehole fluid.

Further, in the case of installing a filter device not intended for cementing below, after lowering the column, the ball 32 is discharged with its seat on the saddle 31 in the axial channel of the cup 28. In the case of two-stage cementing, the ball 32 is discharged after pumping and selling the grouting mortar first ( lower) cementing stages.

After the ball is planted in the pipe string, excess pressure is raised, while the buffer liquid through the bypass holes 37 in the body of the cup 28, the holes 27 in the body of the sleeve 22 and the circulation holes 26 in the body of the barrel 3 enters the annular chamber 4 with an effect on the cross-sectional area of the annular sleeve 8 and the end face of the hollow rod 9.

As the pressure increases, the shear element 16, which connects the hollow rod 9 to the housing 1, is first destroyed. The hollow rod 9 moves downward with the expansion cone 10 acting on the pack of sealing packers 11 of the packer, with their radial deformation together with the extrusion washer 13 being sealed the pipe surface of the previous casing and the overlap of the annular annulus.

With a further increase in pressure in the column and the annular chamber 4, the shear element 15 connecting the annular sleeve 8 with the housing 1 is destroyed. The annular sleeve 8 moves up to the stop in the sleeve 5, and the hydraulic connection of the axial channel of the pipe string with the annulus opens through radial holes 43 in the body of the housing 1 (see Fig. 2). This moment is noted on the surface by the pressure drop in the column.

After that, the calculated volume of grouting fluid is pumped, which, when the annular sleeve 8 is in its highest position, from the axial channel of the pipe string, through the bypass holes 37, the circulation holes 26, combined with the holes 27, is fed into the annular chamber 4 and then through radial holes 43 in the body of the housing 1 - into the annulus of the well.

After pumping the estimated volume of the cement slurry, a separation plug or ball is fed into the pipe casing from the surface and the squeezing fluid is pumped into the string, bringing the separation plug or ball to the nut 21, inserted into its axial channel and mounted on the landing seat 35 in a stepwise curtain 33.

Under the action of excess pressure, the step curtain 33, together with the separation plug (not shown in the figure) moves inside the sleeve 22 after the shear element 36 is destroyed, with the annular protrusion 34 coming out of the interaction with the petal heads of the upper collet 23. This leads to the exit of these heads out of the interaction with the landing sleeve 19 and the joint movement of the cup 28 with the sleeve 22 down in the stepped axial channel 38 of the barrel 3 all the way into the protrusion and the location of the heads 25 of the petals of the lower collet 24 at the level of technological otochki 39. This cup 28 comes to its end face 29 of interaction with an inner ledge 30 on the heads 25 of the collet lower lobe 24 and is reset to the bottom of the well (see. FIG. 3, the dividing tube is shown as a ball onto the valve seat 35).

When the heads 25 of the petals of the lower collet 24 are located in the technological groove 39, the petals of the upper collet 23 are located under the landing sleeve 19, which leads to the fixing of the sleeve 22 inside the axial channel 38 of the barrel 3 and the circulation holes 26 overlap by the body of the sleeve 22, with isolation of the annular space from the annular.

In this position of the parts, hardening of the cement is expected and then the well is developed.

Claims (1)

A device for stepwise cementing of casing strings, including a housing with holes, shear sleeves, shear elements connected to it, seat seats in an axial channel, a packer sealing assembly, a landing mechanism, characterized in that the device is equipped with a barrel installed in the axial channel of the housing to form annular chamber, hydraulically connected with the axial bore of the barrel, with a stepped bore, in which the landing sleeve with the inner annular protrusion, preloaded by the nut, is sequentially placed henna collet with petals, the heads of which are located inside the annular protrusion of the landing sleeve, the lower collet with petals equipped with an inner annular protrusion, the landing valve in the form of a cup with a seat in the axial channel mounted in the axial channel of the sleeve with the possibility of support on the annular protrusion of the petals of the lower collet and a step curtain with an external annular protrusion equipped with a landing seat mounted inside the glass with the possibility of interaction with the heads of the petals of the upper collet and the shear element associated with it , in the annular chamber there is a landing mechanism in the form of an annular sleeve and a hollow rod, at the lower end of which there is an expandable cone with a restrictive ring, and the barrel is equipped with a nut with an extrusion washer and a package of sealing cuffs, and bypass openings are made in the glass, combined with holes in the body sleeves and circulation holes in the barrel with an annular chamber hydraulically connected by radial holes in the housing with the annulus of the well.

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