RU2766980C1 - Device for suspension and cementing of liner in well with preliminary disconnection from transport string - Google Patents

Abstract

FIELD: construction; oil and gas industry.

SUBSTANCE: invention relates to construction of oil and gas wells, namely to devices for lowering, suspension and cementing of blind strings and liners. Device for lowering of hanger and cementing of liner in well includes unit for disconnection of liner hanger, containing disconnecting sub with lock thread for connection with transportation string in upper part and an external left trapezoidal thread for connection to the housing of the device from below, an anchor-packer assembly consisting of an anchor and a packer installed in the hollow housing of the device, in which a hollow rod with radial holes is also installed. Anchor-packer assembly and the hollow rod form an internal annular cavity of the device, with which the anchor-packer assembly has a hydraulic communication channel. Besides, the device comprises a cementing plug suspension assembly including a suspended cementing plug fixed by means of shear screws in the lower part of the hollow rod, the lower end of which is freely suspended, and the upper end is fixed inside the disconnecting sub. Hollow rod has a hydraulic channel for communication through radial holes with an internal annular cavity of the device, which is hydraulically isolated from above and from below by sealing cups. Cementing plug suspension assembly additionally contains mounting bushing for ball, made with external longitudinal projections conjugated with mating internal slots of suspended cementing plug. Landing bushing and the suspended cementing plug are fixed on the sleeve of the hollow rod independently of each other.

EFFECT: preliminary, before cementing, disconnection of liner from transport string without loss of hydraulic connection with it.

1 cl, 10 dwg

Description

The invention relates to the construction of oil and gas wells, and in particular to devices for lowering, hanging and cementing hidden columns and liners.

It is well known that when cementing liners, accidents may occur due to the inability to disconnect the transport string from the liner when the cement slurry is already pumped, which after a certain time begins to harden and after hardening does not allow any work related to the elimination of the accident in the well. Such accidents are called "reinforced concrete in the well." The impossibility of separating the transport string and the liner happens for various reasons: skew of the left threaded connection due to bending of the wellbore and jamming (connection), failure of the disconnect unit, insufficient torque of the drilling rotor when turning off the left threaded connection, etc.

A device for installing and sealing a casing liner in a well is known (patent RU2377391, IPC E21B 33/14, publ. 12/27/2009), including a hollow body, a perforated pipe and a liner connected to each other by means of couplings. The hollow body is connected to a disconnector, which is connected to the transport column with a squeezing plug installed in it. The disconnector is equipped with a cup at the top, having the possibility of hermetic interaction with the inner walls of the hollow body, and at the bottom it is equipped with a hollow branch pipe and a hollow rod with holes telescopically installed into it from below. The hollow stem has the ability to interact with the check valve in the working position. A packer and an anchor are installed in the upper part of the hollow body.

The disadvantage of analogue is that the specified device for installing and sealing the liner involves running and installing the liner in the casing string without cementing, and if it is necessary to cement the liner, the device does not provide high-quality work due to the impossibility of using separating cementing plugs.

Known site casting for cementing additional columns (patent RU174927, IPC E21B 33/05, publ. 11/15/2017), which allows mechanical disconnection of the upper part of the casting unit from the additional column before cementing, while maintaining tightness. The unit consists of two parts - lower and upper, contains a check valve, filling and cleaning plug, made of easily drillable materials. The lower part is attached to the lower end of the additional column and includes a stop-shoe, in which filling holes are made, and a check valve connected to the stop-shoe by a branch pipe. At the same time, the drilled parts are rigidly fixed relative to the equipment body and are protected from rotation, which reduces the drilling time. The non-return valve contains a retainer for the cleaning plug, which, after fixing, together with the non-return valve, acts as a stop ring. The upper part of the casting unit, in turn, consists of an outer part connected by means of a coupling to the upper end of the additional string and containing a polished sleeve with a left-right sub and an adapter, and an inner part. The inner part includes a cleaning plug with a set of cuffs and chevrons, a latch for fixing the filling plug in it and a tip with a lock, a shear sleeve with shear pins and a nipple with sealing elements connected by means of a sleeve and a branch pipe to a mating left-right sub, which allows perform mechanical disconnection of the upper part of the casting unit from the additional string prior to cementing while maintaining tightness and reduces the risk of accidents at high well inclination angles, when turning back is difficult.

The disadvantage of the analogue is that the mechanical disconnection of the casting unit from the column is carried out with the column shoe resting on the bottom by turning the inside of the filling unit from the outside. This method of cementing the string with unloading the weight of the string to the bottomhole is a technological violation, since there is no fixation of the string from possible movement, which negatively affects the quality of cementing.

A device for lowering the hanger and cementing the liner string in the well is known (patent RU2441140, IPC E21B 43/10, publ. a funnel of the anchor-packer unit having a hydraulic drive, and in the inner cavity of which a hollow rod with radial holes is installed, forming an annular cavity with the body of the anchor-packer unit. The disconnect sub is equipped with a left connecting (trapezoidal) thread for connection with the guide funnel, while the anchor and packer units are combined and consist of a shaped pipe, which is installed between the upper and lower end subs, and the lower part of the annular cavity of the device is sealed with sealing collars, and in its the upper part is equipped with a plunger fixed by shear elements and blocking the communication channel between the hydraulic chamber communicated with the internal cavity of the hollow rod and the internal space of the shaped pipe, while the upper end of the hollow rod is fastened pivotally movable by installing the upper suspension coupling with a hemispherical surface in the mating surface of the disconnect sub, and at the opposite end of the hollow rod there is a fixation unit for a suspended cementing plug, including a lower sleeve with a suspended cementing plug fixed to it by means of shear screws, and the plug fixation unit enters the inner cavity of the liner branch pipe, which is connected to the lower end sub from the upper side, and to the liner from the lower side. Taken as a prototype.

The disadvantage is the limited functionality, which does not allow to prevent possible complications when cementing the liner, for example, if there are problems with separation, when the cement is already pumped into the well, and there is a danger of creating an emergency situation (hardening of the cement and leaving it in the string).

The technical problem solved by the invention is the expansion of the functionality of the device to ensure trouble-free work when cementing liners.

EFFECT: preliminary (before cementing) disconnection of the liner from the transport string without loss of hydraulic communication with it.

The problem is solved, and the technical result is achieved by a device for lowering the hanger and cementing the liner in the well, including a liner hanger disconnect unit, containing a disconnect sub with a locking thread for connecting to the transport string in the upper part and an external left trapezoidal thread for connecting to the device body from below, anchor - a packer assembly consisting of an anchor and a packer installed in the hollow body of the device, in which a hollow rod with radial holes is also installed, while the anchor-packer assembly and the hollow rod form between themselves an internal annular cavity of the device, with which the anchor-packer assembly has the hydraulic communication channel, in addition, the device contains a cementing plug suspension unit, including a suspended cementing plug fixed by means of shear screws in the lower part of the hollow rod, the lower end of which is freely suspended, and the upper end is fixed inside the disconnect sub, Why the hollow rod has a hydraulic channel of communication through the radial holes with the internal annular cavity of the device, which is hydraulically isolated from above and below by sealing collars. In contrast to the prototype, the suspension plug of the cementing plug additionally contains a landing sleeve for the ball, made with outer longitudinal protrusions associated with the mating internal grooves of the suspended cementing plug, and the landing sleeve and the suspended cementing plug are fixed on the hollow rod coupling independently of each other.

In particular cases, a catcher basket for a landing sleeve with a ball is installed in the lower part of the liner string, and the hollow rod is made of tubing (tubing).

The technical result is achieved by using the proposed device, which eliminates the risks of an emergency during cementing and leaving cement in the well due to the following.

After lowering the liner to the planned depth, preliminary (before cementing) the liner hanger is anchored in the casing string, the transport string is disconnected from the liner and the transport string together with the hollow rod is raised by approximately 0.5-1.0 m (while maintaining hydraulic communication), after which the liner is cemented. At the same time, the shape of the liner string remains relatively straight, and its axis is close to the axis of the well - thereby providing the necessary clearance between the wall of the well and the liner, which has a positive effect on the quality of well cementing. This is ensured by preliminary, prior to cementing, hanging the liner string at anchor and separating the transport string from the liner.

Disconnection of the transport string (drill pipe string) from the liner is carried out in advance, prior to cementing, by pre-activating the anchor by dropping the shut-off ball into the drill pipe (transport string), fitting it into the landing sleeve and creating excess internal pressure. After that, the transport string is unloaded to its own weight and the transport string is separated from the liner hanger. The presence of a hollow rod with sealing cuffs makes it possible to lift the hollow rod up (by 0.5-1 m) after disconnecting the transport string from the liner hanger, without disengaging from the device body, while maintaining the hydraulic communication channel between them. The hydraulic communication channel is a prerequisite for cementing work, because. work is carried out under conditions of significant hydraulic pressure (up to 250 kgf/cm ² ). Leakage of the communication channel leads to disruption of the cementing process and accidents.

The essence of the invention is illustrated by drawings, which shows the claimed device:

Fig. 1 - device in the transport position in the well, general view (longitudinal section);

Fig. 2 - cementing plug suspension unit (longitudinal section in the area of shear screws of the landing sleeve);

Fig. 3 - cementing plug suspension unit (cross section in the area of the shear screws of the landing sleeve);

Fig. 4 - device after activation of the anchor and separation from the transport column, general view (longitudinal section);

Fig. 5 - cementing plug suspension unit (longitudinal section in the area of shear screws of the suspension plug);

Fig. 6 - cementing plug suspension unit (cross section in the area of shear screws of the suspension plug);

Fig. 7 - device after activation (anchor, packer), general view, longitudinal section;

Fig. 8 - view of the anchor after activation (anchor rams extended);

Fig. 9 - view of the packer in the activated position (the sealing element is opened);

Fig. 10 is a general view of the lower part of the device in the well after completion of cementing.

The figures show:

1 - drill pipe;

2 - disconnect sub;

3 - guide funnel of the shank;

4 - hollow rod (tubing - tubing);

5 - casing packer;

6 - sealing element of the packer;

7 - upper sealing cuff;

8 - packer piston;

9 - opening of the packer's hydraulic chamber;

10 - internal annular cavity of the device;

11 - anchor annular;

12 - anchor dies;

13 - anchor piston;

14 - anchor shear screws;

15 - opening of the hydrochamber of the anchor;

16 - radial holes of the hollow rod;

17 - casing of the suspension unit for cementing plugs;

18 - lower sealing cuff;

19 - landing sleeve for the ball;

20 - waste ball;

21 - suspended cementing plug;

22 - shank;

23 - casing string;

24 - hollow rod coupling;

25 - shear screw of the landing sleeve;

26 - shear screw of the suspension plug;

27 - blind cementing plug;

28 - shank shoe;

29 - cementing holes;

30 - liner check valve;

31 - catcher basket;

32 - "stop" ring;

33 - casing cement.

The proposed device consists of three functional units (Fig. 1):

I - liner suspension disconnect unit (from the transport string);

II - anchor-packer unit;

III - cementing plug suspension unit.

The liner hanger disconnect unit is designed to disconnect the liner from the transport string, consisting of drill pipes 1. The unit consists of a disconnect sub 2, containing in the upper part a locking thread for drill pipes 1 and an external left trapezoidal thread for connection with a guide funnel 3 of the liner in the lower part . The hollow rod 4 can be made of a tubing pipe, installed inside the device containing the packer 5, the anchor 11, and forms an annular cavity 10 with them, isolated by means of the upper 7 and lower 18 sealing collars, and has a hydraulic channel of communication with the device cavity through the radial holes 16. The upper end of the hollow rod 4 is hermetically fixed inside the disconnect sub 2, and the lower end is freely suspended and contains the elements of the cementing plug suspension unit - the landing sleeve 19 and the suspension cementing plug 21, fixed to it by means of shear screws.

Anchor-packer assembly (for fixing the liner and sealing the annulus) consists of an annulus packer 5 for sealing the annular space of the liner 22 and casing 23, and an anchor 11 for fixing the liner string 22 in the casing 23. Packer 5 and anchor 11 have hydraulic communication with the cavity 10 of the device through the holes 9 of the packer hydraulic chamber and the anchor holes 15, and the anchor and the packer contain cylindrical pistons 8 and 13, respectively, placed in the annular cavity (hydrochamber) of the packer 5 and anchor 11. Cylindrical pistons 8 and 13 have a conical end for wedging action on the sealing element 6 of the packer and the ram 12 of the anchor and their movement in the radial direction (advancement) when the pistons 8 and 13 move during the activation of the packer 5 and the anchor 11.

The cementing plug suspension assembly consists of a landing sleeve 19 for a throwing ball 20 and a hanging cementing plug 21. the process of cementing the liner 22 and activating the packer 5. The landing sleeve 19 is made with external longitudinal protrusions, and the suspension cementing plug 21 is with reciprocal internal grooves, and they are fixed on the sleeve 24 of the hollow rod 4 by means of shear screws 25, 26 (Fig. 2 and 5 ).

The device works as follows.

The bottom of the liner string 22 is assembled with technological equipment in the following sequence: liner shoe 28, liner pipe with side cementing holes 29, check valve 30, catcher basket 31, "stop" ring 32, and the liner 22 is lowered into the well with a length determined by the work plan. Further, the inventive liner suspension device is installed on the last pipe of the liner string, onto which the drill pipe 1 (Fig. 1) of the transport string is screwed, and the liner 22 is lowered on the drill pipes to the design depth with intermediate washings. At the end of the descent of the liner 22, the well is washed and the liner 22 is fixed in the casing string 23 by activating the anchor 11 (anchoring). To do this, a ball 20 is thrown inside the upper pipe of the transport string, which, falling, passes through the entire transport string, enters the hollow rod 4 of the device, sits in the saddle of the seat sleeve 19 and closes the central flushing hole of the suspension of the cementing plug 21. The flushing fluid is supplied by turning on the mud pump and creating an excess in-line pressure (40-50 kgf/cm2), which is transmitted through the radial holes 16 of the hollow rod 4 into the annular cavity 10 of the device and through the working hole 15 into the hydro-chamber of the anchor. In this case, the hydraulic pressure acts on the end surface of the piston 13 of the armature 11 and creates the dynamic pressure necessary to shear the screws 14 that fix the piston 13, and leads to its longitudinal movement in the direction of the dies 12 of the anchor. At the same time, the conical surface of the piston 13 exerts a wedging effect on the anchor slips 12, and the latter, having mating surfaces with the piston cone 13, extend in the radial direction and penetrate with the teeth into the body of the casing string 23, wedging the body of the device, and with it the suspension of the liner 22.

Further, by creating an excess of excess pressure (over 50 kgf / cm ² ), the screws 25 are cut, fixing the landing sleeve 19 with the ball 20. The latter, under the influence of their own weight, fall into the lower part of the shank 22 and fall into the catcher basket 31, installed between the shoe 28 and the "stop" ring 32, while not blocking the central passage.

Next, the reliability of the liner fixation is checked by unloading the weight of the transport string by its own weight and the transport string is disconnected from the liner 22 by right rotation of the drill string 1 and the lapel on the left threaded connection of the disconnect sub 2. To confirm the fact of separation, the transport string is lifted to a height 0.5-1.0 m, while the weight on the drilling hook (according to the weight indicator) must correspond to the weight of the transport column.

Liner cementing. After pumping the estimated volume of cement slurry from the cementing head, a blind cementing plug 27 is released and the cement slurry is forced over it. The blind plug 27, having passed through the entire transport string, enters the hollow rod 4, sits in the suspension cementing plug 21 and closes the central hole. As a result, the intrapipe pressure increases, and when a certain value of excess pressure is reached (ΔР-30kgf/cm ² ), the screws 26 fixing the suspension plug 21 are sheared, and under the action of the injection pressure, both cementing plugs 21 and 27 move together down to the "stop" - rings 32 where they overlap the central bore of the shank. At the same time, there is a sharp increase in the inline pressure (“stop” signal), which is transmitted through the radial holes 16 of the hollow rod and the holes 9 of the packer to the piston 8 of the packer, and the screws that fix the piston of the packer and its longitudinal movement in the direction of the sealing element 6 of the packer occur. . Similar to the anchor unit, the conical surface of the piston 8 exerts a wedging effect on the sealing element 6 of the packer, and the latter, under the action of dynamic forces, moves apart in the radial direction and is tightly pressed against the inner surface of the casing 23, thereby hydraulically isolating the annulus of the packer body 5 with the casing 23.

After cementing of the liner 22 is completed, the transport string with the hollow rod 4 and the sealing collars 7 fixed on it are lifted until it disengages from the liner hanger body and flushing is performed to flush out the remaining cement mortar. After flushing, a complete lifting and disassembly of the inner (retrievable) part of the liner hanger is carried out, including: a disconnect sub 2 with a hollow rod 4 and sealing collars 7. The following remains in the well: guide funnel 3, packer body 5 and anchor 11, while the internal the section corresponds to the inner diameter of the liner string itself and allows for downhole operations.

Claims (1)

A device for running a hanger and cementing a liner in a well, including a liner hanger disconnect assembly, containing a disconnect sub with a locking thread for connection to the transport string in the upper part and an external left trapezoidal thread for connection to the device body from below, an anchor-packer assembly consisting of an anchor and a packer installed in the hollow body of the device, in which a hollow rod with radial holes is also installed, while the anchor-packer unit and the hollow rod form between themselves an internal annular cavity of the device, with which the anchor-packer unit has a hydraulic communication channel, in addition, the device contains a cementing plug suspension unit, including a suspension cementing plug fixed by means of shear screws in the lower part of the hollow rod, the lower end of which is freely suspended, and the upper end is fixed inside the disconnect sub, the hollow rod having a hydraulic communication channel black without radial holes with an internal annular cavity of the device, which is hydraulically isolated from above and below by sealing cuffs, characterized in that the cementing plug suspension unit additionally contains a landing sleeve for the ball, made with external longitudinal protrusions associated with reciprocal internal grooves of the suspension cementing plug, and the landing bushing and suspension cementing plug are fixed on the hollow rod coupling independently of each other.

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