RU2236556C1 - Drillable mechanical packer - Google Patents

Abstract

FIELD: mining industry, particularly for sealing oil and gas well annuity and for isolating bottom water.

SUBSTANCE: packer has shaft with releasing cone, body with metal sealing unit equipped with outer and inner annular extensions, anchor, fixer and seating mechanism. Shaft additionally has conical seat and screwed-in member connected to coupling through extender having ring. Adapter is arranged in axial extender channel and have longitudinal windows located in end part thereof. Adapter also comprises sleeve forming sliding connection with shaft. Anchor is made as stops arranged in body windows and cooperating with conical seat. Fixer is made as split retaining rings arranged in annular body grooves and facing mating shaft grooves. Seating mechanism is made as releasing cone located on lower shaft end and spring-loaded dies located on inner annular extension of sealing unit. Body is provided with spring centrator surrounding extender with ring and telescopically connected with it. Axial shaft channel is connected with well cavity by radial channels and have check valve.

EFFECT: increased reliability.

7 dwg

Description

The invention relates to the mining industry and is intended to overlap the annular space of oil and gas wells during the waterproofing of bottom water.

Known packer device (see AS No. 1118760, M. cl. E 21 B 33/12. Publ. 15.10.84, Bull. No. 38), consisting of a barrel on which a head is installed with a sealing element, based on the support sleeve, as well as the retainer and retainer retainer with a fitting sleeve as part of the casing, the retainer is made in the form of a threaded nut spring-loaded relative to the support sleeve, connected to the barrel by a spline connection and having a thread on the outer surface for interacting with the thread of the landing sleeve.

To overlap the annulus, the packer assembly is lowered into the well to the location of the threaded fit sleeve and sits on the protrusion of the support sleeve. By right-handed rotation of the pipe string, the threaded nut is engaged with the mating thread of the landing sleeve. When the estimated axial force arising from the interaction with the threads of the fittings and communicated to the sealing element, the latter loses its stability at the place of execution of the internal grooves and is deformed in the radial direction with the formation of tight contact with the inner surface of the fittings.

Disadvantages. The device can only be used in a new well stock when launching and equipping the barrel with a casing string, into which a threaded fit sleeve is introduced.

The sealant is made of plastic material capable of plastic deformation.

The device cannot be used in the old well stock, since there is no way to equip the casing with a special landing sleeve.

The device is intended for use mainly in newly drilled steam injection wells under cyclic conditions of temperature and pressure.

If there are mechanical particles on the seating surface of the threaded sleeve, problems may arise associated with the tight fit of the seal.

The transmission of rotation to the threaded nut from the surface in order to deform the seal in the radial direction does not allow controlling the torque, and hence the axial force.

Known heat-resistant packer (see and.with. No. 1548405, M. cl. E 21 B 33/12. Publ. 07.03.90, bull. No. 7), containing a hollow barrel, the fixation unit of the packer, a seat with a ball in axial bore of the barrel, a housing with a sealing element fixed to it, an expanding cone and spacer fixing elements - slips along its perimeter. The sealing element is made in the form of a cylindrical shell of elastic material with an expansion unit in the form of balls interacting with the inner surface of the shell and the surface of the expanding cone.

The packer is planted by creating excess pressure over the expanding cone of the slips and transferring pressure to the cone of the expansion unit while rotating the string of pipes of the packer barrel and rolling (expanding) the balls of the cylindrical metal shell until it contacts the inner surface of the casing string. The slots of the anchor assembly mesh with the casing and keep the packer in its original position when transmitting torque to the barrel during radial deformation of the seal.

The axial channel of the packer barrel is released from the saddle with the ball by exceeding the working fluid pressure in comparison with the landing pressure and dumping the saddle with the ball to the bottom.

Disadvantages of the packer design: if necessary, have a sufficiently large dimensions of the axial channel of the packer barrel, comparable with the dimensions of the axial channel of the tubing, with a small diameter of the casing, it is difficult to place the structural elements of the packer, in particular, expandable cone, for landing anchors to create sufficient force to ensure the introduction of the teeth of the anchor into the wall of the casing. To ensure that the seal is seated in this case, it is also necessary to sharply increase the pressure of the working fluid. But after landing the packer and releasing the axial channel from the seat with the ball, it is necessary to create a higher pressure to cut off the calibrated pins, which leads to a sufficiently large hydraulic shock and its negative impact on the design of the packer, in particular, on the sealing element, which even loses its tightness with a slight movement relative to the wall of the casing.

A packer device is known (see AS No. 1153040, M. Cl. E 21 B 33/12. Publ. 30.04.85, Bull. No. 16). The packing device includes an installation sleeve with a support protrusion and a packer comprising a barrel, a sealing head mounted on it, on which the seal is arranged in the form of a cylindrical shell, a latch interacting with the support protrusion of the installation sleeve, a restrictive nut connected by a keyway to the sealing head. The latch is made in the form of an annular protrusion on the seal, which is equipped with a restrictive ring, and the sealing head is made with a bypass valve, closed by a check valve.

Packer device operation.

The installation sleeve is part of the production casing when it is lowered into the well.

The packer on the tubing string is lowered into the borehole until it contacts the support lip of the seal with the end face of the installation sleeve. Loading by weight of the pipe tubing string breaks the shear element and moves the barrel until it stops with a nut into the end surface of the sealing head and move it inside the seal with expansion in the radial direction until the ring protrusion comes into contact with the fixing chamfer of the installation sleeve.

Disadvantages:

- the need to transfer torque to the packer barrel to ensure the deformation of the sealing element in the radial direction, which complicates or even does not allow to control the landing, because with increasing load on the barrel as the diameter of the rolling of the sealing element changes, the pipe string resiliently twists and interacts with the casing wall columns;

- if necessary, drill the packer, there is a need to exclude the rotation of the structure when the cutter interacts with it, since the anchor can absorb axial loads, but the packer barrel resting on the balls can rotate with the cutter, which can increase the working time spent on drilling the device;

- the packer cannot be used to carry out the process of installing a waterproofing screen under it and to perceive the overpressure of the grouting material at the baffle plate.

Known drillable packer (see AS No. 1832148, M. cl. E 21 B 33/12, publ. 07.08.93, Bull. No. 29). Drill packer consists of a hollow cylindrical body, with a threaded thread on the outer surface, above the sealing element. Above, the upper slips are installed in the form of annular sectors with radial grooves and hooks connected by shear screws to the upper support. Above the upper slips there is an upper pusher with longitudinal grooves on the outer surface, in which the upper ends of the holding elements are placed and fixed in the form of strips with hooks on the side surfaces, the lower ends of the strips are placed in the radial grooves of the upper slips. At the lower end of the case, the lower slips are in the form of annular sectors. Under the slips on the case, there is a lower pusher rigidly connected to the pipe, and the last one with a shank, between which a shear ring is placed.

The upper and lower pushers are equipped with clamps in the form of split rings, with a threaded thread on the inner and outer surfaces, installed with the possibility of interaction with the same thread on the body and pushers.

Packer job.

To understand the operation of the packer, it must be deployed 180 ° from the position shown in the description, since the landing tool is connected to the packer at the location of the retaining ring and is connected to the pipe tubing through the shank.

The drilled packer is lowered into the well to a predetermined depth using a planting tool. When creating axial force from the fluid pressure, the force is applied to the upper plunger, as a result of which the sealing element is deformed, and the upper and lower slips come into contact with the inner surface of the casing, and with the calculated force, the ring is cut and the landing tool is disconnected from the drilled packer.

Known packer (see US Pat. RF №2162137, Mkl. 7 E 21 B 33/12, publ. 01/20/01, Bull. No. 2), consisting of a pipe made of easily expandable material, placed on its outer surface with a sealant in the form of an elastic shell expanding the landing cone, connected with the cylinder and with each other by calibrated shear elements, a disconnector, a landing mechanism (drive).

The packer is planted by applying excess pressure to the actuator, which contributes to the introduction of an expanding seat cone under the seal, and its expansion in the radial direction, ensuring tight contact with the casing wall. With increasing pressure on the disconnector, a cut-off shear element is cut and the drive is removed from the borehole along with the cylinder and pipe string.

The design drawback is that for radial deformation of an elastic seal made of ductile metal, a sufficiently large axial force is required, which is created by the perception of excess pressure of the working fluid by the drive piston. At the same time, for wells with a small casing diameter, it is difficult to have a sufficiently large diameter of the drive piston, or it is necessary to increase the packer landing pressure, and hence the pressure at which the calibrated shear element should collapse, which in turn will lead to a hydraulic shock under the packer.

Thus, there are conditions under which the packer can be torn from the installation site by the shock wave, and therefore, the tightness of the sealing element will be impaired.

Known drillable packer and landing tool (see US Pat. RF No. 1747674, M. C. E 21 B 33/12, publ. 15.07.92, Bull. No. 26), taken by the authors for the prototype. The drilled packer includes a hollow barrel with radial holes, lower and upper sub, a casing mounted on the barrel and forming an annular chamber with the latter, a piston with a locking assembly, a sealing element on the hollow housing between the upper ram of the upper sub and the piston, an additional piston with a locking assembly in the annular chamber of the casing under the radial holes of the hollow barrel, the locking unit of each piston is made in the form of a collet connected to the mating part of the hollow barrel, the main and additional pistons tanovleny movably in opposite directions. The lower sub is made in the lower part with a seating thread on the inner surface.

In the design of the drilled packer, a known unit for fixing the deformed sealing element in the form of teeth on the inner surface of the hollow body, which are introduced into interaction with the reciprocal annular grooves, is used. Design disadvantages:

- with a small diameter of the casing string, it is difficult to carry out an annular piston of a sufficiently large cross section to provide the necessary seating force of the sealing element and create the necessary contact stresses with the casing wall;

- the presence in the design of a large number of calibrated shear elements connecting with each other a number of parts, requires accurate execution and coordination of the efforts of their operation - shear, while maintaining the sequence of their destruction, which is very difficult to put into practice;

- the need to use a special landing valve installed in the axial bore of the barrel using cable technology, requires additional work time. After the drilling of the packer being drilled, the axial bore of the barrel is freed from the landing valve, which makes it possible to have a constant hydraulic connection between the sub-packer cavity and the axial bore of the barrel and the tubing string.

In the case of various technological operations in the under-packer area, for example, the operation of isolating the bottom water with injection of an insulating composition under the packer, with the existing design does not exclude its entry into the cavity under the pistons, which will ultimately complicate further dismantling of the packer from its place installation; the absence of a check valve in the axial bore of the barrel after depressurization, at which the insulating composition was pumped, the latter can freely fill the axial bore of the barrel and the tubing string, which will also make it difficult or even impossible to remove the landing tool from the bore.

Pat. RF №2164587, M.cl. 7 E 21 B 34/06 “Device for blocking the string of tubing” (publ. 03/27/01, Bull. No. 9). The device consists of a housing with longitudinal windows in the lower part, an anchor assembly with a drive mechanism containing a core connected to a pusher with a calibrated shear element, a set of one-arm levers connected by a ring, the heads of which are located at the level of the external annular groove of the housing. The core and body are telescopically connected to each other. The fixing unit contains a collet covering the housing, provided with an inner annular protrusion included in the annular groove of the housing. The sealant is located on the collet under the ring of one-arm levers with the possibility of interaction with the grip. The expanding cone is rigidly connected to the core and the lower end of the collet.

The operation of the device.

At the required depth, the tension is transmitted through the pusher to the housing with the input of the heads of the single-arm levers into the first from the bottom joint of the pipes of the coupling connection with the end contact. Then carry out the supply of a cylindrical section under the heads of one-arm levers, preventing them from coming out of interaction with the pipe end.

The technical result that can be obtained by implementing the invention is reduced to the following:

- the possibility of mechanical landing of the packer with reliable overlapping of the annular space with a combined rubber-metal sealant due to the tension of the pipe tubing;

- the ability to transfer torque to the packer barrel when disconnecting the pipe tubing with mechanical fit-fixing the packer by introducing into the pipe joint the coupling connection of the clamps;

- the possibility of radial deformation of the sealing element due to the interaction of the expanding cone on the barrel with crackers covered by the lower end of the sealing element;

- the ability to disconnect and remove from the well an adapter with a spring centralizer after pumping the insulating composition into the subpacker zone while maintaining the tightness of the subpacker zone from the overpacker one.

The technical result is achieved by the fact that in a drillable mechanical packer containing a housing, a barrel, an expandable cone, a sealing element, an anchor, a retainer and a landing mechanism, according to the invention, the barrel is additionally equipped with a landing cone and a screwdriver connected through an extension provided with a ring to the coupling in the axial channel of which an adapter is installed, equipped with longitudinal windows in the end part and a sleeve forming a movable connection with the barrel, the anchor is made in the form of stoppers installed in the case windows with the interaction with the barrel’s landing cone, the latch is made in the form of split retaining rings installed in the annular bores of the body and facing the return grooves on the barrel, the landing mechanism is made in the form of a expanding cone on the lower end of the barrel with spring-loaded crackers mounted on the inner ring protrusion of the sealing element, while the housing is equipped with a spring centralizer, covering the extension cord with the ring, with the possibility of forming a telescopic connection with it, and the axial channel of the stem la is connected with the cavity of the well and is provided with radial channels return valve.

When conducting patent research on scientific, technical and patent literature, we did not find designs of mechanical packers in which the landing-deformation of the sealing element is carried out when the barrel is tensioned and the axial load is transmitted through the intermediate element to the combined metal seal to ensure its radial plastic deformation to form a tight contact with the inner surface of the casing.

When conducting patent research on scientific and technical literature, we did not find designs of mechanical packers in which the seating-deformation of the sealing element is carried out through crackers covered by the sealing element and installed with the possibility of interaction with the expanding cone on the packer barrel when the pipe string is tensioned.

Thus, the achieved technical result is due to the unknown properties of the parts of the device in question and the relationships between them.

The invention does not explicitly follow from the prior art, that is, it meets the criterion of "inventive step".

The design of the device for overlapping the annular space is intended primarily for wells with a small diameter of the casing string, where it is necessary to conduct insulating work from the inflow of bottom water when using a pipe string, the diameter of the axial channel of which is comparable to the diameter of the axial channel of the packer barrel.

The design of the drilled mechanical packer is illustrated by drawings, where:

figure 1 shows the design of a mechanical packer in its original (transport) position;

figure 2 - design of the mechanical packer in the preparation for landing position (stoppers in contact with the inner surface of the casing);

figure 3 - the design of the mechanical packer in the preparation for landing position (stoppers introduced into the joint of the pipe coupling coupling of the casing);

figure 4 - the mechanism of fixation of the barrel of the packer circlip;

figure 5 - design of the mechanical packer in the position of the landing-deformation of the metal seal;

figure 6 - design of a mechanical packer at the end of the sale of insulating mortar (the moment of landing of the upper cementing plug);

Fig.7 - mechanical packer in the operating position after disconnecting the spring centralizer, extension cord and adapter with a sleeve.

The mechanical packer consists of a housing 1 connected through an adapter 2 with a sealing element 3 made in the form of a thin-walled metal shell. In the axial channel 4 of the housing 1, a barrel 5 is installed, provided with an expanding cone 6, at the lower end passing into an annular protrusion 7, and a check valve 8 in the axial channel 9, made stepwise. On the outside of the barrel 5, notches 10 are made with a calculated pitch and a cylindrical groove 11 with a seating cone 12. The housing 1 is provided with radial windows 13 in which stoppers 14 are installed that enter the cylindrical groove 11 of the barrel 5. The sealing element 3 is provided with crackers 15 covering the barrel 5, the axial channel 9 of which is hydraulically connected by radial channels 16 to the well cavity. The barrel 5 is equipped with a screwdriver 17, which is connected through an extension 18 and a sleeve 19 with an elevator pipe string.

On the outside of the housing 1, a spring centralizer 20 is mounted, fixed on it by a shear element 21. The extension 18 is provided with a ring 22, forming a telescopic connection with the housing of the spring centralizer 20. An adapter 23 is installed in the axial channel of the extender 18, provided with a sleeve 24 with a support protrusion 25 that enters the bore in the barrel 5 and rests on the end of the screw-driver 17. At the upper end of the adapter 23, longitudinal windows 26 are made for connecting the axial channel 9 of the barrel 5 with an annular gap between the extension cord 18 and the adapter 23. The adapter 2 of the housing 1 contains spacer washers 27, between which spring circlip 28 is mounted with bevels facing the barrel 5. The orientation of the stoppers 14 relative to the landing cone 12 on the barrel 5 is performed due to the latches 29 installed in the holes of the housing 1 and included in the longitudinal grooves 30 of the stoppers 14.

The annular gap between the barrel 5 and the housing 1 is blocked by the sealing cuffs 31. The annular gap between the sleeve 24 and the barrel 5 is closed by the sealing ring 32.

Work drilled mechanical packer.

The tubing string is connected to the coupling 19, and the device is lowered into the well to a predetermined depth. The spring centralizer 20 during descent is in constant contact with the inner surface of the casing.

The right rotation of the pipe pipe string, reported to the extension 18, carry out its unscrewing from the housing 1 with a speed control. The tension of the elevator string, communicated through the screw-driver 17 to the barrel 5, moves it relative to the housing 1 against the stop by the landing cone 12 into the reciprocal bevels of the stoppers 14 with their movement in the radial windows 13 of the housing 1 until they contact the inner surface of the casing. By further pulling up the whole arrangement, the stoppers 14 are brought to the location of the nearest pipe joint of the sleeve joint of the casing string and inserted inside between the pipe ends (see FIG. 3). In this case, the stoppers 14 extend outside the housing 1, and the barrel 5 occupies a position in which the groove 11 is located above the stoppers 14. In this position of the structural elements, the mechanical packer is fixed in the pipe joint.

By further tensioning the barrel 5, the expanding cone 6 is brought into interaction with the counter cone of the crackers 15 and they are moved in the radial direction. In this case, the radial force is imparted to the sealing element 3, which is plastically deformed and increases its diameter to a diameter equal to the inner diameter of the casing with the formation of a tight connection with it. The notches 10 on the outer surface of the barrel 5 are at the level of the locking rings 28 in the adapter 2, which leads to their entry into the notches 10 and the fixing of the barrel 5 relative to the housing 1. The radial channels 16 are located between the sealing collars 31, which leads to the termination of the axial hydraulic connection channel 9 of the barrel 5 from the well cavity after landing the packer. In this position, a separation plug is installed in the axial channel of the pipe tubing string (not shown in the drawings), then the calculated volume of the insulating composition is fed into the axial channel of the pipe tubing string and the squeeze plug is dumped. Pressurize the working fluid and move the squeeze plug down. When moving the separation plug along the axial channel of the elevator column, the buffer fluid through the check valve 8 enters the under-packer cavity and then into the reservoir. The separation plug under excessive pressure moves down and enters the axial channel of the adapter 23 (see Fig.6). Estimated overpressure open the channel in the separation plug and pump the insulating composition into the under-packer zone. Monitoring the end of the injection process - by the pressure jump at the mouth when the squeeze plug fits onto the separation plug (see Fig. 6). Relieve pressure in the tubing string. Overpressure in the sub-packer zone the check valve 8 is introduced into the stepped bore of the axial channel 9 of the barrel 5 and isolates the sub-packer zone from the over-packer.

The right rotation of the pipe tubing, which is communicated through the extension 18 to the screw 17, takes it out of interaction with the barrel 5. The tension of the lift column moves the extension 18 with the ring 22 relative to the spring centralizer 20. The screw 17 interacts with the support protrusion of the sleeve 24 and puts it out of interaction with the barrel 5. In this position, a hydrodynamic connection is formed between the axial channel of the pipe tubing through the longitudinal windows 26 at the end of the adapter 23 and the annular gap between it and the extension 18 with the annulus in order to ensure the leakage of the working fluid from the tubing string when the extension cord 18, adapter 23 and spring centralizer 20 are lifted from the well, the separation and squeezing plugs remain in the axial channel of the adapter 23 and are removed to the surface together with the extension 18 and adapter 23 (see Fig. .6, 7).

In this position, the well is equipped with downhole equipment for the development and production of formation fluid.

The design of the mechanical packer involves, if necessary, drilling.

Claims (1)

A drillable mechanical packer comprising a housing, a barrel, an expandable cone, a sealing element, an anchor, a retainer and a landing mechanism, characterized in that the barrel is further provided with a landing cone and a screwdriver connected through an extension provided with a ring with a sleeve in the axial channel of which an adapter is installed equipped with longitudinal windows in the end part and a sleeve forming a movable connection with the barrel, the anchor is made in the form of stoppers installed in the windows of the housing with the possibility of interaction with the landing cone with the barrel, the latch is made in the form of split retaining rings installed in the annular bores of the body and facing the return grooves on the barrel, the landing mechanism is made in the form of an expanding cone at the lower end of the barrel and spring loaded crackers mounted on the inner ring protrusion of the sealing element, while the housing equipped with a spring centralizer, covering the extension cord with the ring, with the possibility of forming a telescopic connection with it, and the axial bore of the barrel is connected with the cavity of the well by radial channels alami and equipped with a check valve.

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