RU2757889C1 - System with a fixating ring for use in hydraulic formation fracturing operations - Google Patents

Abstract

FIELD: engineering elements.

SUBSTANCE: slide valve for opening one or several holes for a liquid in a pipe column, characterised by the presence of a body of the valve and a sliding coupling in the longitudinal channel thereof. The body of the valve is characterised by the presence of one or several holes for a liquid in a part thereof located higher in the shaft of the borehole. The sliding coupling is configured to move in the body of the valve between the closed position located higher in the wellbore, wherein one or several holes for a liquid are closed, and the open position located lower in the wellbore, wherein the holes are open. The sliding coupling is characterised by the presence of a longitudinal channel for placing a collet, and/or a locking ring, and/or a protective coupling. The locking ring forms a thrust shoulder to prevent movement of the collet down the wellbore relative to the sliding coupling.

EFFECT: protective coupling prevents cement or debris from entering the annular section between the channel of the body of the valve and the sliding coupling, thus providing freedom of movement of the sliding coupling for opening said holes for a liquid.

30 cl, 63 dwg, 1 tbl

Description

The technical field to which the present invention relates

The present invention relates generally to a downhole tool, and in particular to a downhole tool having a retaining ring system and / or a protective collar for use in fracturing operations.

BACKGROUND OF THE INVENTION

Downhole tools are widely used in the oil and gas industry. Many downhole tools contain pressure-activated valves. For example, a ball-actuated spool valve known in the art comprises a tubular valve body having a bore and a sliding sleeve disposed in the bore. The sliding sleeve comprises a ball seat at its up-bore end and is initially in an up-well closed position in which it blocks one or more fluid openings on the side wall of the valve body. To activate the spool valve, the ball is dropped and seated in the ball seat of the sliding sleeve. Then, fluid pressure is applied to the ball to move the sliding sleeve down the wellbore to an open position to expose the fluid ports on the valve body.

One or more ball activated spool valves may be used in a fracturing process to fracture a subterranean formation. However, a problem with cascading multiple ball-actuated fracturing spool valves is that the bore of the downhole spool valve must be smaller than the bore of the up-bore spool valves to allow the smaller ball to pass through these spool valves. up-hole spool valves to achieve the target down-hole spool valve. In other words, the channels of the cascaded spool valves must be reduced from top to bottom of the wellbore to ensure successful operation, thereby resulting in a decrease in flow rate at the downhole end.

US Pat. No. 4,043,392 to Gazda discloses a downhole system for selectively securing downhole tools along a flow guide device in a wellbore and a drill string for use in a flow direction device comprising a set mandrel, a collar displacement device, and a downhole shutoff device. The selective fixing system is characterized by the presence of a support and fixing profile with recesses, containing upward and downward facing thrust shoulders. One type of detent system is a sliding sleeve valve that includes a cam release shoulder to release the selector and detent key when the sleeve valve is moved between spaced longitudinal sections. Another type of latching system can be positioned along the support nipple and requires that the tool, which is secured therein, cannot release the selector and the latching tools. The sleeve biasing device is characterized by the presence of means for opening and closing a valve with a sliding sleeve, containing keys, characterized by the presence of up and down facing thrust shoulders and profiles with recesses that are compatible with the support and retaining profile with the recesses of the valve with the sleeve or the support nipple. The sleeve biasing device can also be used as a locating mandrel. Selectivity is ensured by changing the seating and fixing profiles and key profiles.

The spring loaded key profiles described in document US 4043392 are not compatible. The key profile only engages the sliding sleeve with the mating inner profile.

US Pat. No. 4,436,152 to Fisher, et al. Discloses an improved switching tool that can be coupled to a tool string and used to engage and position a sliding sleeve in a sliding sleeve device in a flow guide device. Selective profiled changeover tool keys fit better with slide sleeves and provide a larger contact area between the keys and slide sleeves. When the engaged sliding sleeve cannot move upward and the shifting tool is not automatically disengaged, emergency disengagement means may be used by applying an upward force to the shifting tool sufficient to shear the pins and sink all keys inward at both ends for complete disengagement. disengaging to remove the switching tool from the sliding sleeve device.

Collins, US Pat. No. 5,305,833, discloses a shift tool for sliding sleeve valves for use in oil and gas wells that includes setting wedges that are used to selectively set and engage with a shoulder within the valve. The main keys engage and selectively slide the sliding sleeve into the aligned position and also prevent premature sliding to the fully open position. A device for selectively ignoring the post-alignment shear prevention is also provided. The secondary keys guide the primary keys in the shear direction and engage and move the sleeve to the fully open locking position. There is also provision for selectively disengaging the switching tool from the sleeve valve to retrieve the switching tool from the wellbore. In addition, a method of selectively and sequentially moving a sliding sleeve for a valve with a sliding sleeve from a closed position to an alignment position and then from an alignment position to a fully open position is disclosed.

In particular, US Pat. No. 5,305,833 discloses two separate spring-loaded keys, the first of the two keys being able to fit into the profile of the second of the two keys. However, the second key cannot fit into the profile of the first key.

US Pat. No. 5,309,988 to Shy, et al. Discloses a subterranean well flow control system comprising a series of movable collar-type flow control devices installed in a device to direct flow downhole in various fracture zones containing fluid and switch a device configured to move through the device for directing the flow and selectively shifting any selected number of sleeve portions of the flow control devices in any direction between their open and closed positions, without removing the tool from the device for directing the flow. Sets of radially retractable fastening and shear dowels are positioned in the openings of the side wall of the tool body, and they are suitably designed to engage with the sets of grooves on the inner side surface of the body and movable sleeve parts of any of the flow control devices. The key sets are spring loaded radially outward in the direction of the extended positions, and an electromechanical drive system located in the tool body is designed to radially retract the key sets as well as axially move the shear key set towards or away from the set of dowels. This allows the tool to be moved to or through any of the flow control devices in any axial direction, secured to the device, sliding its sleeve part in whole or in part in any direction, and then disengaging from the flow control device and moving to any other of the devices. flow control to shift its coupling part. The intermeshing triangular threads on the body and coupling portions of each flow control device facilitate a detachable coupling of the coupling portion in a partially displaced position.

US Pat. No. 5,309,988 also discloses two incompatible key profiles.

US Pat. No. 5,730,224 to Williamson, et al. Discloses a subterranean structure for controlling tool access to a sidetrack from a wellbore. The underground structure contains a sleeve that is located in the wellbore and adjacent to the hole leading to the sidetrack of the wellbore, and that contains an access window passing through it to provide access of the tool to the sidetrack through the hole. The sleeve additionally contains a sliding access control device axially connected to it. A shear means is also provided that can engage with the sliding access control device to shift the sliding access control device between an open position in which the tool can pass through the window and hole into the lateral retraction of the wellbore, and a closed position in which the tool cannot pass through the window and hole into the sidetrack of the wellbore. This patent also discloses a method for controlling tool access to a sidetrack extending from the wellbore. The preferred method includes the steps of: 1) placing a sleeve in the wellbore close to the hole leading to the sidetrack of the wellbore, and the sleeve is characterized by the presence of an access window passing through it to provide access of the tool to the sidetrack of the wellbore through the hole, the sleeve is additionally characterized by the presence a sliding access control device axially connected thereto; 2) engaging the sliding access control device with the sliding means for sliding the sliding access control device relative to the sleeve; and 3) sliding the sliding access control device between an open position in which the tool can pass through the window and hole into the sidetrack and a closed position in which the tool cannot pass through the window and hole leading to the sidetrack wellbore.

US Pat. No. 5,730,224 discloses two key profiles, one of which has an opposite shape to the other.

Murray, US Pat. Nos. 7,325,617 and 7,552,779, disclose a system for sequentially processing sections of a zone. Each part can be accessed by means of a sliding sleeve, which is characterized by a special internal profile. Injection plugs can be used, which have a special profile that secures the plug to a special sleeve. The pressure acting on the fixed plug ensures the sequential opening of the couplings, while isolating the already involved zones located below. Injected cement plugs are characterized by the presence of a passage that is initially closed with material, which ultimately disappears under the expected well conditions. As a result, when all parts of the zone have been processed, the flow path is re-established through the various fixed plugs. Plugs can also be extruded from the sliding sleeve after use and can contain a key that then prevents the plug from rotating on its axis if re-drilling is required.

US Pat. No. 9,611,727 to Campbell, et al. Discloses an apparatus and method for fracturing a hydrocarbon containing formation in a well. The device contains a valve subassembly assembled with casing sections to create a well casing. The valve subassembly contains a sliding piston that is secured in place to seal openings that provide communication between the interior of the well casing and the pay zone. A dart containing a lip seal may be inserted into the well casing and retractable with pressurized fracturing fluid until the dart reaches the valve subassembly to isolate the well casing under the valve subassembly. The force of the fracturing fluid on the dart and lip seal causes the piston to move downward, shearing the pins and exposing the holes. The fracturing fluid can then be discharged from the fracture holes in the pay zone.

US Pat. No. 9,739,117 to Campbell, et al. Discloses a method and apparatus for selectively activating a downhole tool in a pipe. A driven tool is characterized by a drive mandrel containing a drive bore extending therethrough, a bypass valve and a key for selective engagement with the downhole tool. The downhole tool contains one or more shaped receiving elements configured to actuate the downhole tool. The driven tool is moved into the pipe and engaged with the downhole tool if the key and the shaped receiving element match, and the driven tool and the downhole tool are not engaged if the profile key and the profile receiving element do not match. The fluid can be circulated through the drive channel to flush or clean the space in front of the driven tool.

US Patent Publication 2003/0173089 to Westgard discloses a full bore selective positioning and orientation system comprising a nipple that can be installed in a pipe string and is characterized by having internal positioning and alignment elements of known configuration, and a positioning device configured to descent inside the pipe string and characterized by the presence of positioning and orienting elements that can engage with the specified internal elements of the specified nipple. The method for positioning and orienting a downhole tool involves installing a tubular nipple having a specific configuration of internal dimensions in a pipe string, lowering a positioning device characterized by a complementary configuration of external dimensions to engage with the specified configuration of internal dimensions, and rotating said positioning device to a position in which the displaced member protrudes from said positioning device into a recess in said tubular member.

US Patent Publication No. 2015/0226034 to Jani discloses an apparatus and related methods for selectively actuating sliding sleeves in subs that are located downhole to open holes in such subs for fracturing or detonating. explosive charges to perforate the wellbore, or both. A simplified dart and sleeve are used, which reduces the number of machining operations carried out with each of them. The dart is preferably equipped with connecting means to allow a retrieval tool to be coupled thereto, which, when the retrieval tool is connected, allows a bypass valve to be operated to assist in retrieving the dart from the valve sub. Upward movement of the retrieval tool allows the wedge to disengage the dart element from its associated sleeve for retrieval of the dart.

US Patent Publication 2014/0209306 to Hughes, et al. Discloses a wall-mounted wellbore treatment tool in which a wellbore treatment tool may be located. A tool for treating a wellbore comprises a tool body comprising a first end for connection to a pipe string and an opposite end; a non-passable key assembly containing a tubular casing and a non-passable key, the tubular casing forms an inner channel extending along the length of the tubular casing and an outer face surface on which the non-passable key is located, the non-passable key being configured to fix the non-passable key and the tubular casing in a fixed position with respect to the boundary wall, the tubular casing encloses the tool body so that the tool body is mounted in an inner bore of the tubular body; and a sealing member surrounding the tool body and located between the first compression ring on the tool body and the second compression ring on the tubular casing, the sealing member can expand to form an O-ring around the tool body by compression between the first compression ring and the second compression ring.

In the publication of US patent No. 2015/0218916 issued to Richards, et al., Circulation sleeves are disclosed that can be opened and closed, as well as permanently closed. The completion system contains a completion string, characterized by the presence of a circulation sleeve located therein with the possibility of movement, and the circulation sleeve is characterized by a fixing profile formed on its outer radial surface and a shear profile formed on its inner radial surface, a service tool configured positioning at least partially within the completion string; and comprising a switching tool characterized by one or more shear-responsive keys configured to mate with the shear profile. When the shear keys are positioned and mated with the shear profile, the axial load applied to the service tool causes axial movement of the circulation sleeve, with the release shoulder assembly located within the completion string and containing a release shoulder that defines a bore configured to accommodate a retainer mechanism occupying the channel until the release shoulder moves in the axial direction.

Canadian Patent No. 2412072 to Fehr, et al. Discloses a tubing assembly for fluidizing a wellbore. The tubing string can be used for staging the wellbore with fluid, with the other segments being isolated while treating a selected segment of the wellbore. The tubing string can also be used if the perforated tubing string is to be run tightly and then opened.

Alternative and / or improved designs that provide consistent and reliable engagement and actuation of subsurface valves, as well as improved sealing, are always of great interest in the fracturing field.

The essence of the invention

In one aspect of the present invention, there is provided a slide valve for opening one or more fluid openings in a tubing string. The sliding sleeve contains:

- a valve body, characterized by the presence of a longitudinal channel, and the valve body contains the specified one or more openings for a fluid medium located above the wellbore part of its side wall; and

- a sliding sleeve positioned for sliding movement in the longitudinal bore of the valve body and configured to move between an up-borehole closed position, in which one or more fluid openings are closed, and an open position down-borehole, in which one or more fluid openings are open;

moreover, the sliding sleeve contains: a longitudinal channel and a profile of the sleeve on it to accommodate a unique fixing profile of the collet element; and a stop ring, on the up-borehole lateral edge of which there is a stop shoulder abutting against a part of the unique retaining profile of the collet element when said unique retaining profile engages with the specified profile of the sleeve and prevents the collet element from moving down the wellbore relative to the sliding sleeve ...

In some embodiments, at least said abutment shoulder of said retaining ring has a hardness that is greater than that of the sliding sleeve material, or it comprises a material having a hardness that is greater than that of the sliding sleeve.

In some embodiments, said retaining ring is comprised of a material having a hardness that is greater than that of the sliding sleeve.

In some embodiments, at least said shoulder of said retaining ring is comprised of a material selected from the group of materials including tungsten carbide, cobalt-chromium alloys, nitrided steels, or combinations thereof.

In some embodiments, said sleeve profile on said sliding sleeve is located uphole relative to the retaining ring.

In some embodiments, the thrust shoulder forms an acute angle with respect to the longitudinal axis of the spool valve such that the inner edge of said thrust shoulder is located higher up the wellbore than the outer edge of said thrust shoulder.

In some embodiments, the sliding sleeve further downhole with respect to said retaining ring further comprises a connecting portion; and the specified sliding sleeve further comprises a protective sleeve, and located above the borehole end of the specified protective sleeve is connected to the specified connection part, the specified protective sleeve extends down the wellbore; and the retaining ring is an annular element; and the sliding sleeve further comprises a retaining ring seat for positioning the retaining ring between the retaining ring seat and an uphole end of the shielding sleeve.

In some embodiments, the shielding sleeve defines an annular space between a portion of its outer periphery and said valve body when the sliding sleeve is in a closed position; and a protective sleeve insulates the annular space from the second channel.

In one aspect of the present invention, there is provided a slide valve for opening one or more fluid openings in a production string. The sliding sleeve contains:

- a valve body characterized by the presence of a longitudinal channel, and the valve body contains one or more openings for a fluid medium located above the wellbore part of its side wall;

- a sliding sleeve, characterized by the presence of a longitudinal channel and a profile of the sleeve on it, and the sliding sleeve is placed with the possibility of sliding movement in the longitudinal channel of the valve body and is configured to move between a closed position located above the wellbore, in which one or more holes for the fluid medium closed, and located below the wellbore open position in which one or more openings for the fluid are open; and

- a collet element placed in the longitudinal channel of the sliding sleeve and characterized by a unique locking profile, said unique locking profile is made with the possibility of mating engagement with the specified profile of the coupling;

wherein the sliding sleeve further comprises a retaining ring defining a first abutment shoulder that prevents the collet element from moving downhole relative to the sliding sleeve when said unique locking profile of said collet element mates with said sleeve profile of said sleeve element.

In some embodiments, at least said abutment shoulder of said retaining ring has a hardness that is greater than that of the sliding sleeve material, or it comprises a material having a hardness that is greater than that of the sliding sleeve.

In some embodiments, said retaining ring is comprised of a material having a hardness that is greater than that of the sliding sleeve.

In some embodiments, at least said stop shoulder of said stop ring is hard enough to be equal to that of the downhole portion of the unique retaining profile of said collet element.

In some embodiments, the stop collar shoulder is comprised of a material having a hardness approximately equal to that of the downhole portion of the unique retaining profile of said collet element.

In some embodiments, at least said shoulder of said retaining ring is comprised of a material selected from the group of materials including tungsten carbide, cobalt-chromium alloys, nitrided steels, or combinations thereof.

In some embodiments, said sleeve profile on said sliding sleeve is located uphole relative to the retaining ring.

In some embodiments, the thrust shoulder forms an acute angle with respect to the longitudinal axis of the spool valve such that the inner edge of said thrust shoulder is located higher up the wellbore than the outer edge of said thrust shoulder.

In some embodiments, the sliding sleeve further downhole with respect to said retaining ring further comprises a connecting portion; and said sliding sleeve further comprises a protective sleeve, wherein an upbore end of said sleeve is connected to said connecting portion, said sleeve extending down the wellbore. The retaining ring is an annular element; and the sliding sleeve further comprises a retaining ring seat for positioning the retaining ring between the retaining ring seat and an uphole end of the shielding sleeve.

In some embodiments, the shielding sleeve defines an annular space between a portion of its outer periphery and said valve body when the sliding sleeve is in a closed position; and a protective sleeve insulates the annular space from the second channel.

In some embodiments, said unique collet retaining profile includes a stop shoulder at its downhole end to engage with the stop ring stop shoulder.

In some embodiments, the thrust shoulder on said collet element forms an acute angle with respect to the longitudinal axis of the spool valve, whereby the inner edge of said thrust shoulder on said collet element is located higher up the wellbore than the outer edge of said thrust shoulder on said collet element.

In some embodiments, the unique retaining profile of said collet member is a radially flexible collet profile configured to mate with said sleeve profile on said sliding sleeve.

In some embodiments, the collet element further comprises a cylindrical up-borehole portion, a cylindrical down-borehole portion, and a plurality of flexible petals therebetween, connected to an up-borehole and down-borehole portions, on said flexible petals specified unique fixing profile.

In one aspect of the present invention, there is provided a slide valve for opening one or more fluid openings in a production string. The sliding sleeve contains:

a valve body, characterized by the presence of a longitudinal channel, and the valve body contains the specified one or more openings for a fluid medium located above the wellbore part of its side wall; and

a sliding sleeve disposed in the longitudinal bore of the valve body and configured to move between an up-borehole closed position in which one or more fluid openings are closed, and a down-borehole open position in which one or more fluid openings fluid open;

moreover, the sliding sleeve contains:

- the body of the coupling, characterized by the presence of a longitudinal channel; and

- a protective sleeve located below the wellbore relative to the sleeve body;

moreover, at least the connecting part of the protective sleeve is located in the sleeve body for connecting the protective sleeve to the sleeve body;

at least when the sliding sleeve is in the closed position, an annular space is formed between the protective sleeve and the valve body; and

a protective sleeve isolates the annular space from the longitudinal bore of the valve body.

In some embodiments, the slide sleeve further comprises a stop shoulder to prevent the collet from moving downhole in the longitudinal bore of the slide sleeve.

In some embodiments, the thrust shoulder has a first acute angle relative to the longitudinal axis of the spool valve such that the inner edge of said thrust shoulder is located higher up the wellbore than the outer edge of said thrust shoulder.

In some embodiments, the thrust shoulder is formed by a retaining ring housed in a sliding sleeve.

In some embodiments, the sleeve housing includes a retaining ring seat for positioning a retaining ring between the retaining ring seat and an uphole end of the shield collar.

In some embodiments, at least said abutment shoulder is given a hardness that is greater than that of the sliding sleeve material, or it comprises a material having a hardness that is greater than that of the sliding sleeve.

In some embodiments, said retaining ring is comprised of a material having a hardness that is greater than that of the sliding sleeve.

In some embodiments, at least said abutment shoulder is given a hardness equal to that of the unique retaining profile of the collet element.

In some embodiments, the thrust shoulder is comprised of a material having a hardness approximately equal to that of the downhole portion of the unique retaining profile of the collet element.

Brief description of the figures

Additional advantages and other embodiments of the present invention will become apparent from the above description, together with the following detailed description of various specific embodiments of the present invention, taken in conjunction with the accompanying figures, each of which is non-limiting, in which:

in fig. 1 is a cross-sectional view of a spool valve-shaped downhole tool that includes a valve body and a sliding sleeve movable therein, in accordance with some embodiments of the present invention, the sliding sleeve being in a closed position, and showing the protective sleeve being used;

in fig. 2 is a cross-sectional view of a valve body of the downhole tool shown in FIG. 1, without protective sleeve;

in fig. 3 is a cross-sectional view of the sliding sleeve of the downhole tool of FIG. 1, which shows an additional protective sleeve;

in fig. 4 is a cross-sectional view of the body of the sliding sleeve shown in FIG. 3;

in fig. 5 is a cross-sectional view of the protective sleeve of the sliding sleeve shown in FIG. 3;

in fig. 6 is a cross-sectional view of the retaining ring of the sliding sleeve shown in FIG. 3;

in fig. 7 is an exploded sectional view of the sliding sleeve shown in FIG. 3, showing the assembly process of the sliding sleeve;

in fig. 8 is a cross-sectional view of a collet for actuating the slide valve of FIG. 1;

in fig. 9-12A are cross-sectional views of the collet shown in FIG. 8 and the corresponding slide valve shown in FIG. 1, depicting the process of entering the collet into the corresponding spool valve and engaging and locking with it;

in fig. 12B is an enlarged sectional view of a portion of FIG. 12A, which shows the profiled regions of the collet and associated slide valve when the collet is engaged with a lock in the corresponding sliding sleeve;

in fig. 13 is a schematic sectional view of the collet shown in FIG. 8 fixed in the corresponding spool valve shown in FIG. 1, and a ball dropped into the slide valve to move the slide valve to the open position;

in fig. 14 is a schematic cross-sectional view of the slide sleeve of the spool valve shown in FIG. 13, driven by ball and collet pressure to an open position to expose fracturing fluid holes;

in fig. 15A is a schematic cross-sectional view of a slide valve sleeve actuated by ball and collet pressure to open to expose fracturing fluid openings, in accordance with an alternative embodiment, the collet petals may be pressure actuated to expand radially outward when the fluid pressure is directed up the wellbore, and the compression of the collet causes the petals to expand radially outward for additional engagement with the sliding sleeve in order to improve engagement and pressure resistance;

in fig. 15B is an enlarged sectional view of a portion of FIG. 15A showing a radially outwardly flared collet engaging a sliding sleeve;

in fig. 16 is a schematic view of a casing having a plurality of slide valves as shown in FIG. 1 protruding into a wellbore for fracturing a subterranean formation, in accordance with some embodiments of the present invention;

in fig. 17A is a cross-sectional view of a collet in accordance with some alternative embodiments;

in fig. 17B is an enlarged sectional view of a portion of FIG. 17A showing a collet ball seat;

in fig. 18 is a cross-sectional view of a specific example of the collet shown in FIG. 17A housed in the sliding sleeve shown in FIG. 3, and a ball housed in a collet, which is configured to expand radially outward in an expandable metal part of the collet to form a metal-to-metal seal between the collet and the sliding sleeve when the ball fits into the ball seat of the collet and the upward fluid pressure is applied to the ball ;

in fig. 19 is a cross-sectional view of a collet in accordance with some alternative embodiments;

in fig. 20A-20D are schematic views of a plurality of sleeve profiles and their respective collet profiles, according to some alternative embodiments;

in fig. 21A is a schematic view of a sleeve profile and associated collet profile for depicting profile design related parameters;

in fig. 21B is a schematic view showing a collet profile mating with a sleeve profile;

in fig. 21C is a schematic diagram showing the collet profile and the sleeve profile shown in FIG. 21 B, and the collet profile is located in the sleeve profile;

in fig. 22-49 are schematic views of various designs of the profiled regions of the sliding sleeve and collet;

in fig. 50 is a schematic diagram of an example of a pipe string having a plurality of slide valves in accordance with some embodiments of the present invention;

in fig. 51 is a schematic illustration of a set of elongated sleeve and collet profiles according to some alternative embodiments of the present invention;

in fig. 52 is a schematic illustration of a set of elongated sleeve and collet profiles according to some further alternative embodiments of the present invention;

in fig. 53 is a schematic illustration of a set of elongated sleeve and collet profiles according to some other alternative embodiments of the present invention;

in fig. 54-57 are schematic views of a set of elongated sleeve and collet profiles according to some other embodiments of the present invention;

in fig. 58-61 are schematic illustrations of a set of elongated sleeve and collet profiles in accordance with some other embodiments of the present invention;

in fig. 62 is a schematic illustration of a set of elongated sleeve and collet profiles in accordance with some other embodiments of the present invention; and

in fig. 63A-63F are schematic illustrations of a collet profile on a collet and a collar profile on a sliding sleeve, in accordance with some embodiments, wherein the collet tabs may be pressure driven to expand radially outwardly when uphole fluid pressure is applied, and compression of the collet causes expansion. lobes radially outward for additional engagement with the sliding sleeve for improved engagement and pressure resistance.

Detailed description of the invention

In embodiments of the present document, a pressure activated spool valve is disclosed. In the following description, the term "downhole" refers to the direction of the wellbore towards the end of the wellbore, and may coincide (eg, in a vertical wellbore) or may not coincide (eg, in a horizontal wellbore) with the direction downward. The term "up-borehole" refers to the direction of the wellbore towards the surface, and may coincide (eg, in a vertical wellbore) or may not coincide (eg, in a horizontal wellbore) with an upward direction.

In some embodiments, a spool valve includes a valve body characterized by a longitudinal bore and one or more fluid openings on a sidewall thereof. A sliding sleeve is positioned in the wellbore and is movable between an up-wellbore closed position in which the fluid openings are blocked and a down-wellbore open position in which the fluid openings are open.

The sliding sleeve contains a profiled area on its inner surface, consisting of annular grooves and ridges that form the profile of the sleeve. The profiled region includes a stop shoulder at its downhole end for securing a collet element (also called a "collet" for ease of description) characterized by a corresponding collet profile on its outer surface. As used herein, the term “appropriate” means that the collet profile matches the slide sleeve profile, whereby the collet profiled region can be positioned in the slide sleeve profiled region to secure the collet in the slide sleeve of the slide valve.

In some embodiments, the uphole surface of the retainer ring is tilted radially inwardly from the bottom up the wellbore to form a thrust shoulder 194 having an acute angle α with respect to the longitudinal axis of the retainer ring.

In some embodiments, the thrust shoulder is formed by a retaining ring adjacent to the profiled region of the sliding sleeve.

In some embodiments, the retaining ring is made of a high strength material such as tungsten carbide, cobalt chromium alloys, and / or the like.

In some embodiments, the collet is in the form of a sleeve and includes an upbore portion, a downhole portion, and a plurality of longitudinal lobes mounted at their longitudinally opposite ends on upbore and downhole portions. One or more or all of the longitudinal petals are flexible and profiled to form a collet profile.

In some embodiments, the up-borehole portion of the collet includes a ball seat for receiving a ball that is dropped from an up-bore position to actuate a slide valve.

In some embodiments, the collet includes a metal up-borehole portion that expands radially outwardly such that when the collet is positioned in a suitable spool valve and the ball is seated in the ball seat of the collet, fluid pressure on the ball can expand. radially outward of the expandable up-borehole portion and pressing against the inner surface of the sliding sleeve to form a metal-to-metal seal at the interface between the sliding sleeve and the collet.

In some embodiments, the collet ball seat includes an inclined surface.

In some embodiments, the angle of inclination θ of the sloped surface of the ball seat is approximately 55 ° with respect to the longitudinal reference line. In some embodiments, the angle of inclination θ is approximately 35 °. In some alternative embodiments, the angle of inclination θ is from about 50 ° to about 60 °. In some alternative embodiments, the angle of inclination θ is from about 40 ° to about 70 °. In some alternative embodiments, the angle of inclination θ is from about 30 ° to about 80 °.

FIG. 1 illustrates a downhole tool generally designated 100. In these embodiments, the downhole tool 100 is configured as a downhole spool valve and includes a tubular valve assembly 102 characterized by a longitudinal bore 104 and a sliding sleeve 106 disposed in bore 104. Sliding sleeve 106 is secured by one or more shear pins 108 in an uphole closed position in which one or more fluid openings 110 on tubing 102 are closed, and includes a longitudinal bore for receiving a corresponding collet described later herein. Under the action of downhole fluid pressure, the collet can move the sliding sleeve 106 from a closed position to a downhole open position to expose one or more fluid openings 110 for fracturing a subterranean formation (described below).

As shown in FIG. 2, tubular assembly 102 includes a tubular valve body 112 detachably coupled to an upper sub 114 and a lower sub 116 located above and below the wellbore of the wellbore, respectively, through a thread 118 and a locking screw 120, and provided with a seal ring 122 to seal the connection. In these embodiments, the downhole end of the upper sub 114 and the upbore end of the lower sub 116 form the upbore and downhole stops 124 and 126 to restrict movement of the sliding sleeve 106 therebetween.

In these embodiments, the top sub 114 includes an interior surface 128 that tapers from its upbore end to its downhole end so that the top sub 114 gradually decreases from the upbore end to the downhole end. down the wellbore end to facilitate insertion of the collet into spool valve 100 (described below).

The valve body 112 includes one or more fluid openings 110 on its sidewall near the upbore end 132 for discharging high pressure fracturing fluid into the subterranean formation when the sliding sleeve 106 is moved from a closed position to an open position by the action of response pressure. The valve body 112 also includes one or more pin holes 136 through which one or more shear pins 108 (see FIG. 1) extend to lock the sliding sleeve 106 in a closed position to cover the holes 110. The valve body 112 further comprises one or more trapezoidal threads 138 on the inner surface near its downhole end 136.

FIG. 3 is a cross-sectional view of a sliding sleeve 106 and a sleeve body 152 having a bore 151. The sliding sleeve 106 has an outside diameter (OD) equal to or slightly less than the ID of the valve body 112 to allow the sliding sleeve 106 to move within the valve body 112. In these embodiments, the sliding sleeve 106 includes a sleeve body 152 that houses at least a connecting portion 153 of a shield sleeve 154 located downhole therefrom by threads 156 on the inner surface of the sleeve body 152 (see FIG. 4) and corresponding threads 158 on the outer surface of the protective sleeve 154 (see Fig. 5) for connection with the protective sleeve 154 with the possibility of disconnection.

As shown in FIG. 4, the sleeve body 152 may include, on its outer surface, one or more circumferential o-rings 168 at suitable locations as needed, such as near the top end 164 of the sleeve body 152, to seal the contact surface between the valve body 112 and the sliding sleeve 106 (see FIG. Fig. 1).

The clutch body 152 also includes one or more pin holes or recesses 170 at locations corresponding to the locations of the pin holes 136 on the valve body 112 to accommodate the shear pins 108 when the slide sleeve 106 is installed in the bore 104 of the valve body 112 in a closed position, and one or more trapezoidal threaded rings 172 around a downhole end 166 for engaging with trapezoidal threads 138 on the inner surface of valve body 112 when sliding sleeve 106 is in an open position.

On its inner surface, the sleeve body 152 is made of a suitable material, such as steel, and includes a downhole retainer ring seat 180 located uphole of the threads 156 and accessible from the downhole end 166 of the sleeve body 152 for placement and support of the high strength retaining ring 192, and a profiled region 182 located uphole from and adjacent to the retainer ring seat 180 (accordingly, the other region of the inner surface of the sliding sleeve 106 is referred to as the non-profiled region).

The profiled region 182 on the sleeve body 152 comprises one, preferably two or more annular grooves 184, such as grooves 184A and 184B, which form a unique locking profile (also referred to as a “sleeve profile”). Each groove 184 comprises an up-borehole wall that slopes radially inwardly from the bottom up the borehole and has an obtuse angle with respect to the longitudinal axis of the sleeve body 152. Each groove 184 also includes a wall downhole or at a right angle or an acute angle. That is, the downhole wall of each groove 184 is either perpendicular to the longitudinal axis of the sleeve body 152 or tilts radially inwardly from the bottom up the wellbore and forms an acute angle with respect to the longitudinal axis of the sleeve body 152. The grooves 184 allow a collet 200 with a matching outer surface profile 212 ("matching collet") to enter the profiled region 182, with the collets 200 with inappropriate outer surface profiles ("mismatched collets") passing therethrough (described below).

Depending on the number of grooves 184, the ID of the profiled region 182 on the sliding sleeve 106 may vary in different locations in the longitudinal direction due to the presence of the grooves 184. However, the minimum ID of the profiled region 182, including the circlip 192, is generally the minimum ID of the sliding of the sleeve 106. In other words, the minimum ID of the sliding sleeve 106 is located at the portion of the profiled region 184 and the retaining ring 192.

The outer diameter of the collet profile 212 on the collet 200 is greater than the minimum ID of the profiled region 182 on the sleeve body 152 to provide an initial minimum engagement, in the case of a corresponding collet, the collet profile 212 on such a corresponding collet 200 with the profiled region 182 on the sleeve body 152, but in the event of an impact fluid pressure on collet 200 OD of profiled area 212 may significantly exceed the minimum ID of profiled area 182 on sleeve body 152 to maximize engagement of profiled area 212 on collet 200 with profiled area 182, which is described in more detail below.

It is noteworthy that the OD of the collet 200 in the area of the ball seat 214 is initially less than the ID of both the channel 151 and the profiled region 184 on the sleeve body 152. Collet 200, however, is configured to expand radially outwardly at a portion of ball seat 214 when up-borehole fluid pressure is applied to ball 242 as it is seated in ball seat 214 in a manner that is described in more detail below to cause its radial expansion ( i.e., increasing the OD of collet 200 in the area of the ball seat 214) to be very close to or equal to the bore 151 in the sleeve body 152 to provide beneficial effects and benefits that are described in more detail below.

Retaining ring 192 is made of a material having a hardness greater than that of sliding sleeve 106. For example, retaining ring 192 is made of high strength material such as tungsten carbide, cobalt chromium alloys (e.g. Stellite alloys), nitrided steels, and / or other suitable high strength alloys, or combinations thereof, to provide improved pressure resistance and wear resistance.

In some embodiments, at least the thrust shoulder 194 of the circlip 192 (which is described in more detail below) is hardened that is greater than that of the sliding sleeve 106, or it comprises a material having a hardness that is greater than that of the sliding sleeve 106.

FIG. 6 is a cross-sectional view of a high strength retaining ring 192. Retaining ring 192 has an OD suitable to fit into the retainer ring seat 180 of the sleeve body 152 and has a sectional height h sufficient to extend radially inward beyond the inner edge of the retainer ring seat 180. In these embodiments, the up-bore surface of the stop ring 192 is tilted radially inwardly from the bottom up the borehole to form at its up-bore lateral edge a thrust shoulder 194 having an acute angle α with respect to the longitudinal axis of the slide valve 100. As will be more detailed below, the stop shoulder 194 of the retaining ring 192 may abut a portion of the collet profile and engage with a corresponding collet shoulder when the collet profile engages the collar profile 182 and prevents the collet member 200 from moving downhole relative to the sliding sleeve. Thus, the retaining ring 192 may also be referred to as the “retaining ring” to prevent the collet from moving down the wellbore.

As shown in FIG. 7, the slide sleeve 106 may be assembled by inserting the retaining ring 192 into the sleeve body 152 to fit into the retainer ring seat 180. Then, the shield 154 is "screwed" onto the downhole end of the sleeve body 152 by engaging the threads 158 of the sleeve 154 with the threads 156 of the sleeve body 152. The uphole end 160 of the collar 154 presses the retaining ring 192 against the retainer ring seat 180 so that the retaining ring 192 is securely positioned therebetween. The assembled slide sleeve 106 is shown in FIG. 3.

Then, the spool valve 100 can be assembled by inserting the slide sleeve 106 into the bore 104 of the valve body 112 from either end to a closed position, locking the slide sleeve 106 in that position by inserting a shear pin or shear screw 108 through the pin hole 136 of the valve body 112. into the pin hole 170 of the coupling body 152, and then connecting the valve body 112 to the upper sub 114 and the lower sub 116. The assembled spool valve 100 is shown in FIG. 1.

As shown in FIG. 1, the sliding sleeve 106 has a longitudinal length that is greater than the distance between the stops 124 and 126 of the valve body 112 so that when the sliding sleeve 106 is in the closed position, the shield sleeve 154 is in contact with the inner surface of the lower sub 116 to isolate the annular space 196 which is radially between the valve body 112 and the sliding sleeve 106 and longitudinally between the downhole end 166 of the sliding sleeve 106 and the thrust shoulder 126, away from bore 104 to prevent cement from entering the annulus 196, which would disrupt operation valve.

As described above, spool valve 100 includes a profiled inner surface region 182 characterized by a unique retaining profile that can receive and lock a matching collet and pass a non-matching collet therethrough.

FIG. 8 shows a cross-sectional view of a collet 200, which in these embodiments is a cylindrical sleeve having a longitudinal bore 202. Collet 200 generally has an OD (except for locations on the projections 222 described below) that is slightly less than the minimum ID of the sliding sleeve 106. and includes one or more circumferentially extending O-rings 204 on its outer surface at desired locations, if necessary, to seal the contact surface between collet 200 and slide sleeve 106 when collet 200 is locked into slide sleeve 106.

As shown, collet 200 includes a cylindrical up-bore portion 206, a cylindrical down-bore portion 208, and a middle portion 210 having a profiled region 212 with a unique retaining profile.

In these embodiments, the up-wellbore portion 206 includes, on its inner surface, a ball seat 214 for a ball dropped from an up-wellbore position. The uphole portion 206 also includes an o-ring 216 on its inner surface to seal the contact surface between the ball and the upborehole portion 206 of the collet 200.

The middle portion 210 includes a plurality of circumferentially spaced longitudinal petals 218 connected to upbore and downhole portions 206 and 208. In these embodiments, the collet 200 is formed from a metal pipe by cutting, punching, or otherwise creating a plurality of longitudinal slots 220 in the middle 210 to form petals 218.

One or more or all of the longitudinal petals 218 are made of a material with resilient flexibility, characterized by sufficient pliability, and are profiled such that each of them contains one or more protrusions 222, such as protrusions 222A and 222B in the profiled region 212, extending radially outward from their outer surface to form a radially flexible retaining profile (also called a "collet profile"). The positions and sizes of the protrusions 216 are selected such that the maximum OD of the collet 200 is greater than the minimum ID of the sliding sleeve 106 and the profile of the collet matches the profile of the corresponding sliding sleeve 106. Thus, when the collet 200 enters the spool valve 100 with the corresponding sliding sleeve 106 (e.g. spool valve 100 is also referred to as "corresponding spool valve 100"), the collet 200 can be locked into a corresponding sliding sleeve 106. The lower bore lip 222B contains a shoulder 236 on its downhole side, characterized by the same acute angle α relative to the longitudinal axis of the slide valve 100, as well as the thrust shoulder 194.

FIG. 9-12 show an example of the movement of collet 200 into a corresponding spool valve 100 from a position up the wellbore. As shown in FIG. 9, when collet 200 enters spool valve 100, the tapered inner surface 128 of top sub 114 guides collet 200 to enter bore 104.

As shown in FIG. 10, when the profiled region of the collet 200 enters bore 104 and when the maximum OD of the collet 200 is greater than the minimum ID of the sliding sleeve 106, the profiled petals 218 are displaced inwardly and the collet 200 continues to move downhole.

As shown in FIG. 11, when the profiled region 212 of the collet 200 completely overlaps the corresponding profiled region 182 of the sliding sleeve 106, the profiled petals 218 do not move due to their pliability. The collet 200 is thus positioned downwardly in the sliding sleeve 106. As shown in FIG. 12A and 12B, the collet 200 may further move downhole until the shoulder 236 of the lower bore lip 222B engages the stop shoulder 194 of the high strength retaining ring 192.

FIG. 12B shows an enlarged view of the profiled regions 182 and 212 of the sliding sleeve 106 and collet 200. As shown, the profile of each profiled region 182, 212 contains alternating grooves and ridges (or ridges). In the example shown in FIG. 12B, the profile of the profiled region 182 includes two grooves 184A and 184B and a ridge 232 therebetween. The profile of the profiled region 212 comprises two ridges / ridges 222A and 222B and a groove 234 therebetween. To match the profiled regions 182 and 212 to each other, the groove width on either of the two profiled regions 182 and 212 must be equal to or greater than the width of the corresponding ridge on the other of the two profiled regions 182 and 212 to accommodate the corresponding ridge therein. In the example shown in FIG. 12B, the width of the groove (e.g., groove 184A, 184B, or 234) is substantially greater than the width of the corresponding ridge (e.g. ridge 222A, 232, or 222B), so that after the collet 200 is locked down in the sliding sleeve 106, the collet 200 can move further downward. down the wellbore until the lower lip 222B engages the high strength retaining ring 192.

As shown in FIG. 12B, a high strength retaining ring 192 is used to engage the downhole ridge / ridge 222B to improve downhole locking between the sliding sleeve 106 and the high pressure collet 200. Moreover, the retaining ring 192 is shaped such that the up-hole shoulder 194 has an acute angle with respect to the longitudinal axis of the slide valve 100, and the down-hole side of the down-hole protrusion 222 B also forms a shoulder 236 c. an acute angle so that the engagement of the shoulders 194 and 236 provides increased resistance to the downhole pressure applied to the collet 200. In these embodiments, when the shoulders 194 and 236 engage with each other, the other corresponding ridges of the collet 200 and the slide couplings 106, such as ridges 222A and 232, are also engaged to further increase resistance to downhole pressure applied to collet 200.

As shown in FIG. 13, after the collet 200 is secured in the sliding sleeve 106, the ball 242 can be thrown off the surface and can enter the spool valve 100. The ball 242 is made of a rigid material such as ceramic or metal and is sized to fit into the ball seat 214 collet 200.

After the ball 242 enters the ball seat 214 and seals off the bore 202 of the collet 200, fluid pressure is applied from the top of the wellbore to the ball 214 and the collet 200. Since the collet 200 is fixed at the bottom with the sliding sleeve 106, the sliding sleeve 106 is actuated and shears the shear pin 108, and also moves down the wellbore to an open position to expose the fluid openings 110. As shown in FIG. 14, the trapezoidal threaded rings 172 on the sliding sleeve 106 engage with the trapezoidal threads 138 on the valve body 112 to prevent the sliding sleeve 106 from moving up the wellbore. Then, the high pressure fracturing fluid may be pumped down the wellbore and discharged from the fracturing fluid holes 110.

The fracturing fluid is generally under high pressure, and any failure of spool valve 100 may result in failure of the fracturing process. For example, if the engagement between the collet 200 and the sliding sleeve 106 is lost, the high pressure fracturing fluid can move the collet 200 down the wellbore, causing the fracturing process to fail.

As will be appreciated by those skilled in the art, slide valve 100 in the above embodiments includes a high strength retaining ring 192 to enhance engagement between collet 200 and sliding sleeve 106, which greatly reduces the risk of failure.

In some embodiments, the OD of the collet 200 at the projections 222A and 222B is less than the ID of the sliding sleeve 106 at the grooves 184A and 184B. As shown in FIG. 15A and 15B, in these embodiments, after pumping the high pressure fracturing fluid down the wellbore and moving the sliding sleeve 106 to the open position, the high pressure fracturing fluid also slightly moves the collet 200 down the wellbore, thereby causing the petals 218 are forced to expand radially outward such that protrusions 222A and 222B of collet 200 further engage grooves 184A and 184B of sliding sleeve 106 to provide increased pressure resistance.

In some embodiments, a downhole fracturing system comprising a plurality of slide valves 100 can be used to fracture a subterranean formation. FIG. 16 depicts an example of fracturing a subterranean formation using spool valve 100. In this example, a horizontal well is drilled that contains a horizontal portion 272 of a wellbore in a subterranean formation 274. A casing 276 containing a plurality of spool valves 100 is lowered into a wellbore portion 272. Each sliding sleeve 100 contains a unique sleeve profile. The spool valves 100 can be spaced apart from each other by other subs if necessary.

Once the casing 276 has been placed in place, cementing may be performed by pumping liquid cement down the wellbore through the casing 276. As described above and shown in FIG. 1, in each spool valve 100, a protective sleeve 154 prevents cement from entering the annulus 196, which would disrupt the operation of the valve. After cementing, a cleaning fluid can be pumped down the wellbore to clean out the subs containing spool valves 100. Scrapers can also be used to clean up if needed.

In this example, formation 274 around wellbore section 278 is to be fractured and slide valves 100B and 100C must be opened. Thus, the first collet (not shown) corresponding to the spool valve 100C is pressed downhole through the casing 276. Since the first collet does not match the spool valves 100A and 100B (i.e., the profile of the first collet does not match and cannot be placed in the profile of the spool valve clutch 100A and 100B), the first collet passes through the sliding clutches 100A and 100B and is fixed in the spool valve 100C.

To open the fluid openings of the slide valve 100C, the ball is released and it enters the ball seat of the first collet and blocks the passage of the first collet. Then, fluid pressure is applied to drive the engaged ball, the first collet, and the slide sleeve to shear the shear pin of the spool valve 100C and move the slide sleeve down the wellbore to an open position to expose the fluid portions of the slide sleeve 100C.

After opening the 100C spool valve, the second collet corresponding to the 100B spool valve is pressed down the wellbore to lock with the 100B spool valve. Then, the ball is released to engage the second collet and fluid pressure acts to open the 100B slide valve.

After opening all spool valves 100B and 100C in section 278 of the wellbore, the balls in these spool valves, with the exception of the ball in the spool valve located below all down the wellbore, are removed, for example, by drilling, dissolving, retrieving to the surface and / or the like. ... In the example shown in FIG. 16, the ball in spool valve 100C is retained and the ball in spool valve 100B is removed. Then, a high pressure fracturing fluid is pumped into the casing 276 and discharged from the fluid ports of the spool valves 100B and 100C to fracture 274.

In the above example, wellbore isolation devices such as packers can be used to isolate the section of the wellbore to be fractured, which is known in the art and will not be described herein.

As can be understood from the above examples, a plurality of sliding sleeves 100 may be used in the fracturing process, having channels 104 generally of the same size so that a uniform flow of fluid passes through them. Collet 200 and balls 242 can also be of the same size, which simplifies procurement and reduces the cost of completing the well.

In the above embodiments shown in FIGS. 3-7, shield sleeve 154 is releasably coupled to sleeve body 152 by engaging threads 158 and 156. In some alternative embodiments, sleeve 154 may be coupled to sleeve body 152 by other suitable means. For example, in one embodiment, the sleeve 154 may be permanently welded to the sleeve body 152.

In the above embodiments, the collet 200 is a cylindrical sleeve containing a plurality of petals mounted on a cylindrical uphole portion 206 and a cylindrical downhole portion 208, eliminating the use of external means such as springs for radial movement. or changing the shape of the collet 200 to engage and lock in the sliding sleeve. According to a specific additional embodiment, the installation of flexible petals with their longitudinally opposite ends on the upper and lower borehole portions 206 and 208, as well as the collet such that said petals, when initially engaged within the inner profile 184 in the sliding sleeve 106 and under the action of the fluid pressure directed up the wellbore on the ball, located in the ball seat 214 of the collet 200, it is preferable to provide additional radial bending of the petals on the collet 200, which, thereby, leads to an additional and stronger engagement of the petals, characterized by the profile 212 of the collet, in profile 184 of the sliding sleeve 184, which reduces the risk of not engaging the collet 200 with the selected sleeve, or alternatively reduces the risk of possible disengagement of the corresponding profile on the collet 200 with the corresponding profile 184 on the sliding sleeve 106 when the hydraulic fracturing pressure is applied upstream the well, which, in the event of a failure, prevents the injection of high pressure fracturing fluid into the well through open hole 110.

In some alternative embodiments, a downhole fracturing system comprising a tubing string having one or more slide valves 100 may be used to fracture a section of a wellbore. The wellbore can be a cased borehole or an open borehole.

Although in the example shown in FIG. 16, slide valves 100 are used to fracture a horizontal section of a wellbore, it will be apparent to those skilled in the art that, in some alternative embodiments, slide valves 100 may be used to fracture a vertical section of a wellbore.

In the foregoing embodiments, collet 200 may include one or more o-rings 204 on its outer surface to seal the contact surface between collet 200 and slide sleeve 106 when collet 200 enters spool valve 100. However, such o-rings 204 are typically collet travel time down the wellbore can wear out and become ineffective when collet 200 moves in slip sleeve 106, which can cause spool valve 100 to fail. Moreover, when lowering the collet under pressure through inappropriate slide sleeves, high fluid pressure is usually required to overcoming the friction caused by the movement of the o-rings 204 along the inner surface of the sliding sleeve 106.

In some alternative embodiments, the collet 200 should be free of o-rings 204 on its outer surface. In these embodiments, slide valve 100 is the same as shown in FIG. 1, and the non-profiled area of collet 200 has an OD that is slightly less than the minimum ID of sliding sleeve 106, thereby avoiding friction otherwise provided by o-rings 204, and thus allowing collet 200 to pass through an inappropriate spool valve 100 under less fluid pressure. ...

In these embodiments, the sliding sleeve is made of a suitable metal such as steel. As shown in FIG. 17A and 17B, the uphole portion 206 of the collet 200 is characterized by a radially outward expandable metal portion 206 ', and the ball seat 214 comprises a ball seat surface 282 angled radially inwardly from top to bottom along the wellbore at an acute angle of inclination relative to the longitudinal axis 284 of the collet. 200.

Once collet 200 is secured in spool valve 100, a suitably sized ball 242 is lowered by downhole fluid pressure into ball seat 214. When downhole fluid pressure is applied to the uphole side of ball 242, ball 242 is pressed to the sloped surface 282 of the ball seat 214 to convert the downhole fluid pressure to a radially outward pressure and allows the expandable metal portion 206 'of the collet 200 to radially expand to sufficiently close the gap between the collet 200 and the sliding sleeve 106, or even cause the outer the surface of the expandable metal portion 206 'with the inner surface of the sliding sleeve 106 to form a metal-to-metal seal at the contact surface between the collet 200 and the sliding sleeve 106.

As shown in FIG. 17B, the surface 282 of the ball seat 214 is inclined at an inclination angle θ relative to the longitudinal reference direction 284. In some embodiments, the inclination angle θ is approximately 55 °. An angle of inclination of approximately 55 ° is sufficient to transmit the necessary radially outward force to the collet 200 to achieve sufficient radial expansion of collet 200 to form a proper metal-to-metal seal with sliding sleeve 106, for a metal collet with a modulus of elasticity similar to American Petroleum Institute N80 ( API), where the nominal diameter of the ball seat 214 on the collet 200 is 4.555 inches, the nominal collet thickness is 0.23 inches and the pressure on the ball 242 of the nominal diameter 4.250 inches is approximately 1500 psi, with the collet 200 at the beginning, before radial expansion is characterized by a spacing in the range of 0.004 to 0.014 inches from the inner diameter of the sliding sleeve 106 (see Example A below and FIG. 18).

In other embodiments, in which the collet 200 can be made of a stronger or less resilient material (i.e., having a higher modulus of elasticity) and / or thicker, and / or if the initial spacing between the collet 200 diameter and the slide diameter coupling 106 is greater than 0.004-0.014 inches, and / or if the pressure on ball 242 is less than 1500 psi, the angle of inclination θ must be reduced to approximately 35 ° so that the ball seat 214 can transmit sufficient radially outward force to achieve sufficient radial increasing the diameter of the collet 200 to thus achieve the desired metal-to-metal seal with the bore.

In some alternative embodiments, the angle of inclination θ is from about 50 ° to about 60 °. In some alternative embodiments, the angle of inclination θ is from about 40 ° to about 70 °. In some alternative embodiments, the angle of inclination θ is from about 30 ° to about 80 °.

Accordingly, therefore, if the collet 200 is configured to provide radial expansion, this advantageously allows the overall outer diameter of the collet 200 to be reduced. This reduced diameter, not only in the ball seat 214 region but also in the collet profile region 212, allows the collet 200 and 212 of the profile is easier to pass with less interaction with the sections 184 of the profile of the various up-bore sliding sleeves 106, which are not desirable to be driven, thereby reducing friction wear on such a profiled region 212 of the collet 200, but nevertheless, While still maintaining the ability of the collet 200, primarily at the ball seat portion 214, to seal when the collet 200 has reached the target downhole collar 106 and the collet profile portion 212 therein engages the corresponding desired corresponding profile 184 on the collar.

In particular, it is important to note that by exploiting this radial expansion capability of the collet 200, wear on the collet profiles 212 is reduced, thereby maintaining the integrity of the collet profiles 212 and ensuring that when the collet 200 reaches the desired sliding sleeve 106 to be driven into action, the corresponding profile 212 therein may be sufficiently and reliably engaged while simultaneously creating an initial metal-to-metal seal to provide pressure build-up on the up-bore side of ball 242. The increased pressure on the up-bore side of ball 242 after the engagement of the collet 200 with the sliding sleeve 106, in turn, results in a domino effect, in which such an increase in pressure causes (additional) radial expansion of the collet 200, which in turn causes an increase in the metal-to-metal seal, which provides an additional increase in pressure, which, again, it causes increased radial expansion and increased metal-to-metal seal. The upbore pressure continues to build up until it shears the shear pins 108 holding the sliding sleeve 106 in place and moves the sliding sleeve 106 down the wellbore into valve 100 to open holes 110.

FIG. 18 shows an example of a collet 200 according to the present invention slidably disposed in a sliding sleeve 106, said collet 200 being configured according to the above preferred embodiment. In particular, according to such a preferred embodiment, the collet 200 in the area of the ball seat 214 has a thickness, material and initial radial spacing similar to those of the bore 151 of the sleeve body 152, whereby when the ball 242 is seated in the ball seat 214 and the fluid pressure is at least 150 psi acts on it, increasing its outer diameter radially outward by more than 0.09% to provide sufficient metal-to-metal sealing between the outer diameter of the collet 200 at the ball seat 214 and bore 151 of the coupling housing 152. In particular, the outer diameter of the collet 200 in the area of the ball seat 214 can be increased radially outward by the action of fluid pressure on the ball 242 seated therein, preferably to a value of at least 0.09% of the radial increase, preferably to a value of at least 0. 2% radial increase, more preferably to at least 0.3% radial increase, when subjected to an uphole fluid pressure of at least 150 psi to provide a better initial spacing between profiled region 212 on collet 200 and mismatched profiles, but when engaging with the desired profiled region 184 on the selected sliding sleeve 106, provide a seal between collet 200 at the ball seat portion 214 for a domino effect and additional radial expansion of collet 200 to enhance the metal-to-metal seal, thereby expanding radially outward and metal-to-metal seals are sufficient so that the additional pressure is applied to a value sufficient to shear the shear pins 108.

In the foregoing embodiments, the collet 200 is formed from a metal pipe by cutting, punching, or otherwise creating a plurality of longitudinal slots 220 in the middle portion 210 to form the petals 218. In some alternative embodiments, the petals 218 may be connected to the upper and lower wellbore. borehole portions 206 and 208 by other suitable means such as welding, screws and / or the like.

Example "A"

As mentioned above, in FIG. 18 shows an example of a collet 200 according to the present invention slidably displaced in a sliding sleeve 106. Collet 200 is characterized by having a radially expandable portion 206 ″ in a ball seat portion 214.

In particular, in this example, the collet 200 in the area of the ball seat 214 is made of steel API NP 80, characterized by a modulus of elasticity of 29,000,000 and Poisson's ratio of 0.29. Sliding sleeve 106 was also made from API grade N80 steel.

In this selected example, collet 200 was formed with an initial radial clearance at the contact surface between the outer radial periphery of collet 200 at ball seat 214 and inner bore 151 of 0.002-0.007 inch sleeve body 152, which was determined using material tolerances of collet 200, namely the difference between the maximum and minimum dimensional tolerances between the OD of the collet 200 and the inner diameter of the inner bore 151 of the sliding sleeve 106 [(ie, from (4.567-4.553) / 2 to (4.562-4.558) / 2)].

The nominal thickness of the collet 200 in the area of the ball seat 214, namely the up-hole side of the ball seat 214, was 0.149-0.1515 inches [i.e. from (4.553-4.255) / 2 to (4.558-4.255) / 2], and on the downhole side of the ball seat 214 was 0.2305 to 0.233 inches [i.e. from (4.553-4.092 / 2) to (4.558-4.092) / 2].

The angle of inclination θ of the ball seat 214 of the collet 200 was 55 °. Ball 242 has a nominal diameter of 4.250 inches.

When 1500 psi fluid pressure was applied uphole on ball 242 after ball 242 was seated in ball seat 214, the above initial 0.002 "to 0.007" radial spacing was sufficient to initially partially prevent fluid from passing through said contact surface. If the injection of pressurized fluid continues, an increase in fluid pressure occurs up the wellbore of ball 242 due to this partial initial blockage. The radially expandable portion 206 'of the collet 200, in response to the force applied to the ball 242 by the fluid pressure, creates, due to the angle θ of the ball seat 214, a radially outward force applied to the tubular collet 200 in the area of the ball seat 214. The radially outward force causes the metal portion 206 'to expand radially outward, ultimately eliminating or substantially reducing the above 0.002-0.007 inch radial spacing and creating a metal-to-metal seal at the contact surface between collet 200 and sliding sleeve 106.

In particular, the radially outward expandable metal portion 206 'expands radially by at least 0.09% (in the case where the outer diameter of the radially outward expandable metal portion 206' is maximum 4.558 inches, and the ID of the sliding sleeve bore is minimum 4.558 inches, and namely (4.562-4.558 / 4.558), and nominally radially expands 0.02% (assuming the outer diameter of the radially outward expanding metal portion 206 'is nominal 4.555 inches and the sliding sleeve bore ID is nominal 4.565 inches, namely (4.565 -4.555 / 4.555), and expands radially by at least 0.03% (assuming the outer diameter of the radially outward expanding metal portion 206 'is a minimum 4.553 inches and the sliding sleeve bore ID is a maximum of 4.567 inches, namely (4.567- 4.553 / 4.553), which in all cases leads to a decrease in the radial gap with the formation of a metal-to-metal seal between the collet 200 and the sliding sleeve oh 106.

It will be apparent to those skilled in the art that the above parameters may be modified to achieve the desired result of a radially expandable collet that advantageously can reduce contact with the up-bore sliding sleeves as they travel through them to the desired sliding sleeve. 106 and thus maintain size tolerances of the collet 200, in particular in its profile sections 212, and OD in the ball seat section 214, and also easier to go down the wellbore due to reduced diameters, but with a locking engagement with the desired with the selected coupling and when subjected to fluid pressure, it can "increase" to maintain an effective seal and provide sufficient pressure to shear the shear screws 108.

By way of illustration, in this example, sliding sleeve 106 and collet 200 are made of API grade N80 steel. It will be apparent to those skilled in the art that in various alternative embodiments, slide sleeve 106 and collet 200 may be made from another suitable material, such as API grade P110 steel, having a similar modulus to achieve similar radial expansion at 1500 psi pressure. square inch.

However, as an alternative to reduce the discharge pressure, but still achieve a similar radial increase (i.e., a nominal radial increase of 0.02%), collet 200 can be composed of a material with a modulus of elasticity that is an order of magnitude less than the modulus of steel. API NP 80 (i.e. 1/10 of the modulus of elasticity of API NP 80 steel). This results in the need for an actuation pressure, which likewise only needs to be 1/10 of the actuation pressure, namely 150 psi, to still achieve the desired nominal radial increase of 0.02%.

Similarly, by decreasing or increasing the angle θ of the ball seat 214 of the collet 200 as shown in FIG. 18, the effective radially outward force applied by the ball 242 to the periphery of the collet 200 at the ball seat portion 214 can be varied to increase or decrease the amount of radial force applied to the collet 200, respectively.

Thus, for example, with a stable fluid pressure of 1500 psi, decreasing the 0 slope from 55 ° to 30 ° will increase the applied force and decrease the required fluid pressure from 1500 psi, or use a material with a proportionally reduced modulus. elasticity (i.e. using a less rigid material with greater radial elastic deformation per unit of applied force) will achieve a similar magnitude of increase in radial expansion (nominally 0.02%).

Additional modifications and combinations of the aforementioned variables to achieve the aforementioned radial magnifications will be apparent to a person skilled in the art.

For example, if the tilt angle θ was increased from 55 ° to 80 ° with a decrease in the effective radially outward force applied normal to the collet 200, to achieve a similar radial expansion of the collet 200 (nominally 0.02%), this would require one or more of next:

(i) changing the material of the collet 200 to a material with a smaller decrease in the modulus of elasticity (ie, less rigid);

(ii) increasing the 1500 psi fluid pressure on the ball 242 to achieve the same tangential force that was previously applied using an angle of inclination θ equal to 55 °; or

(iii) reducing the thickness of the collet 200 in the area of the ball seat 214 (provided that the applied pressure and the resulting radial force do not exceed the yield strength of the collet 200 in the area of the ball seat 214).

Additional description

FIG. 19 shows a collet 200 according to some alternative embodiments. In these embodiments, slide valve 100 is the same as shown in FIG. 1.

As shown in FIG. 19, the collet 200 according to these embodiments includes a closed uphole end 284. Other portions of the collet 200 are the same as shown in FIG. eight.

In these embodiments, spool valve 100 does not need a ball 242 to be actuated. Instead, a corresponding collet 200 is pressurized down the wellbore and latched into spool valve 100 to actuate spool valve 100. Fluid pressure acts on the closed uphole end 284 of collet 200 to shear the shear pin 108, and causes the sliding sleeve 106 of the spool valve 100 to move down the wellbore to an open position. As described above, the high strength retaining ring 192 provides improved pressure resistance and wear resistance.

In the above embodiments, the slide sleeve 106 includes a high strength retaining ring 192 at its downhole end of the profiled region 182 defining a stop shoulder 194 for securing the associated collet 200. In some alternative embodiments, the retaining ring 192 is made from the same material as and a sliding sleeve 106, but preferably of a higher strength material and / or a hardened material and / or a nitrided material such as, without limitation, tungsten carbide. In some embodiments, at least the stop shoulder 194 of the circlip 192 is hard or has a hardness that is substantially or approximately equal to that of the downhole portion of the profile of the corresponding collet 200.

In some alternative embodiments, the slide sleeve 106 does not include a retaining ring 192. Rather, the up-bore end of the shield sleeve 154 forms a stop shoulder 194 for securing the associated collet.

In some other alternative embodiments, the sleeve body 152 and the shield sleeve 154 are integrally formed to form a sliding sleeve 106 and include a radially inwardly projecting annular ridge defining an abutment shoulder 194. Thus, the sliding sleeve 106 of these embodiments does not include a stop collar. rings 192.

In some alternative embodiments, the sliding sleeve 106 includes only the sleeve body 152 and does not include the protective sleeve 154. In these embodiments, the retaining ring 192 is welded, installed, or otherwise integrated into the sleeve body 152.

In some embodiments, a plurality of sleeve and collet profiles may be produced, and multiple sleeve and collet profiles may be used on the same tubing in a downhole fracturing system.

For example, in FIG. 20A-20D show four sleeve profiles 182-1 to 182-4 (collectively referenced 182) on the inner surface of sliding sleeves 106-1 to 106-4, respectively, and their respective collet profiles 212-1 to 212-4. (collectively designated 212) on the outer surface of the collet 200-1 to 200-4, respectively.

As shown, each clutch profile from 106-1 to 106-4 comprises at least two grooves 184A and 184B (also referred to as “clutch grooves” herein) and one ridge 232 (also referred to as a “clutch flange” herein). located longitudinally between the two grooves 184A and 184 B.

Accordingly, each collet profile from 200-1 to 200-4 includes at least two ridges 222A and 222B (also called "collet ridges" herein) and one groove 234 (also called a "collet groove" in this document) between two ridges 222A and 222B. Moreover, the length of each groove 184A, 184B, 234 is greater than or equal to the length of each ridge 222A, 222B, 232 to accommodate the collet profile 200-1 to 200-4 in the corresponding sleeve profile 106-1 to 106-4.

By varying the lengths of grooves 184A and 184B and flange 232, many unique and individual sleeve profiles (and corresponding unique and individual collet-sleeve combinations) can be obtained. In these embodiments, the length difference between the two sleeve profiles, for example the length difference between the sleeve profiles 182-2 and 182-3, is the result of an integer multiplication of a predetermined design parameter L _b , where L _b > 0. Moreover, the difference in lengths between the respective grooves or ridges of the two sleeve profiles, for example, the difference in the lengths of the grooves 184A of the sleeve profiles 182-1 and 182-2, or the difference in the lengths of the grooves 184B of the sleeve profiles 182-1 and 182-2, is also equal to the result of an integer multiplication a given design parameter L _b , where L _b > 0.

As shown in FIG. 21A, the following parameters (all greater than zero) are used for the coupling profile 182:

L _s - longitudinal length of the profile 182 of the coupling;

S _g1 is the longitudinal length of the groove 184A of the profile 182 of the coupling;

S _r - the longitudinal length of the ridge 232 of the profile 182 of the coupling; and

S _g2 - the longitudinal length of the groove 184 B of the profile 182 of the coupling.

The parameters L _s , S _g1 , S _r and S _g2 are measured at the radially innermost points of the sleeve profile 182.

The following parameters (all greater than zero) are used for collet profile 182:

L _c - longitudinal length of the profile 212 of the collet;

C _r1 is the longitudinal length of the ridge 222A of the collet profile 212;

C _g - longitudinal length of the groove 234 of the profile 212 of the collet; and

C _r2 is the longitudinal length of the ridge 222 B of the collet profile 212.

The parameters L _c , C _r1 , C _g and C _{r2 are} also measured at the radially innermost points of the collet profile 212.

As described above, in a pair of corresponding collet profile and box profile, the lengths of the grooves, including the lengths S _g1 , S _g2 and C _{g of the} grooves 184A and 184B of the box and the grooves 234 of the collet, must be greater than or equal to the lengths of the corresponding ridges, including the lengths C _r1 . C _r2 and S _{r of} collet flanges 222A and 222B and clutch flange 232, i.e. S _g1 ≥C _r1 , S _g2 ≥C _r2 and C _g ≥S _r to allow the collet profile 212 to be accommodated in the corresponding sleeve profile 182.

In these embodiments, the up-bore surfaces of the collar grooves 184A and 184B and the retaining ring 192 are tilted so that they extend radially inwardly up the borehole. The uphole collet flange 222A and 222B surfaces and the downhole collet flange 222B surface are inclined so that they extend radially outwardly down the borehole. These slopes adversely affect the ability to accommodate the collar flange 232 and collet flanges 222A and 222B in the collet groove 234 and the clutch grooves 184A and 184B.

For ease of description, in these embodiments, the uphole surfaces of the collar grooves 184A, 184B, retaining ring 192, collet flanges 222A, 222B, and downhole collet flange 222B surfaces are substantially the same.

As shown in FIG. 21B and 21C, due to the presence of the above-described angular chamfers, after the collet profile 212 is joined with the corresponding collar profile 182, the collet 200 can expand radially outward and further move down the wellbore a short distance ε ₁ , which is the design parameter given by the above-described angular chamfers and the amount of engagement, for placement in the profile 182 of the sleeve until the downhole surface of the collet ridge 222B engages with the stop shoulder 194 of the retaining ring 192.

As shown in FIG. 21A, on the profile 182 of the sleeve, the length S _{r of the} ridge 232 is determined as follows:

where 1≥δ≥0 is a given design parameter, L _a is a given design parameter, and L _a > 0, n is an integer and n≥0, L _b is a given design parameter and L _b > 0. Thus, when n = 0, the ridge 232 has a minimum length S _r = δL _a .

The lengths S _g1 and S _{g1 of the} grooves 184A and 184B are defined as follows:

where m ₁ is an integer and m ₁ ≥1, and m ₂ is an integer and m ₂ > 1. Moreover,

where K> 2 is a positive integer, as a result of which for coupling profiles with the same K, an increase in m ₁ leads to a decrease in m ₂ , which effectively changes the location of the ridge 232 on the coupling profile.

The length L _{s of the} coupling profile 182 is determined as follows:

Since L _a and L _b are predetermined design parameters, it is possible to obtain a plurality of coupling profiles 182 with different lengths L _s by selecting different n and K.

On the profile 212, the collet lengths C _r1 , C _r2 , C _{g of the} ridges 222A and 222B and the grooves 234 of the collet are defined as follows:

where t ₁ , t ₂ and ε ₂ are the given design parameters, and 1≥t ₁ ≥0, 1≥t ₂ ≥0 and ≥ε ₂ ≥0. The length L _{c of the} collet profile 212 is determined as follows:

The parameter ε ₂ only determines whether or not the downhole surface of the collet ridge 222A engages with the downhole surface of the collar groove 184A. In some embodiments, ε ₂ = 0, whereby when collet 200 engages collar 106 under pressure from the top of the wellbore, the downhole surface of the collet ridge 222A engages the downhole surface of the groove 184A of the collar and the downhole surface of collet ridge 222B engages with thrust shoulder 194 to provide increased pressure resistance. In some other embodiments, ε ₂ > 0, together with other conditions (described below), allows flexible tabs 218 to further expand radially outward and flex under fluid pressure for improved engagement between collet 200 and sliding sleeve 106.

As shown in FIG. 21A, according to embodiments in which ε ₂ = 0 when t ₁ = 1, the sleeve groove 184A and the collet ridge 222A have a maximum length difference L _b ; when t ₁ = 0, the sleeve groove 184A and the collet ridge 222A are of the same length. Likewise, when t ₂ = 1, the sleeve groove 184B and the collet flange 222B have a maximum length difference L _b ; when t ₂ = 0, the sleeve groove 184B and the collet flange 222 B are of the same length.

In some embodiments, the design parameters are set as L _a = L _b , t ₁ = t ₂ = t, and 1>t> 0. Then, the parameters of the profile 182 of the coupling take the following form:

The parameters of the profile 212 of the collet take the following form:

Taking into account ε ₂ , the parameter t determines the difference in lengths between the grooves and the corresponding ridges. If t = 0, the sleeve profile 182 and the collet profile 212 have the same length. If t = 1, the sleeve profile 182 and the collet profile 212 have a maximum length difference L _b . In embodiments in which t ₂ = 0 if t = 0, the grooves and their corresponding ridges are of the same length. If t = 1, the grooves and their corresponding ridges are characterized by the maximum difference in lengths L _b .

A number of coupling profiles and collet profiles can be produced. For ease of description, coupling profiles and collet profiles are grouped into profile sets, and profile sets are grouped under profile categories. In this document, the profile of the clutch is represented as follows: "S ({letter of category designation} {set number} - {profile number})", where "{letter of category designation}" can represent A, B, C, etc. ., and represent the profile category to which the sleeve profile belongs, "{set number}" may be 1, 2, 3, etc., and represent the profile set to which the sleeve profile belongs, and "{profile number} "Can be 1, 2, 3, etc., and represent the order of a sleeve profile in a set of profiles. For example, the sleeve profile "S (A1-1)" represents the first sleeve profile in set A1.

Similarly, the profile of the clutch is presented in the form "C ({letter of the category designation} {set number} - {profile number})". For example, "C (B2-3)" collet profile represents the third collet profile in set B2.

As can be seen, a plurality of sleeve profiles 182 and collet profiles 212 are created by varying the values of n, K, and m ₁ . Thus, for ease of description, the sleeve profile can also be denoted as S [n, K, m ₁ ] and the collet profile can also be denoted as C [n, K, m ₁ ].

According to these embodiments, for a given L _b , the sum (n + K) determines the length of the sleeve profile L _s and the length of the collet profile L _c . In particular, the coupling profiles in each profile category (for example, "A") are characterized by the same length L _s = (n + K + 1) L _b , and the collet profiles in the same profile category are characterized by the same length L _c = (n + K + 1-t) L _b .

The parameter n defines the length of the clutch flange 232 and the length 234 of the collet groove. Thus, the profiles of the sleeve in each set of profiles (for example, "A1") are characterized by the same length of the ridge 232 in the form of S _{r =} (n + 6) L _b , and the profiles of the collet in the same set of profiles are characterized by the same length of the groove 234 in the form of C _g = (n + t + 5) L _b + ε ₂ .

Each set of profiles contains (K-2) coupling profiles and (K-2) corresponding collet profiles with the same n and the same K, in which all (K-2) coupling profiles are characterized by the same length L _s = (n + K + 1) L _b and the same S _r = (n + δ) L _b , and all (K-2) collet profiles are characterized by the same length L _c = (n + K + 1-t) L _b and the same C _g = (n + t + δ) L _b + ε ₂ .

It will be apparent to those skilled in the art that if t is equal to or close to 0, then the collet profile completely or almost completely matches the collar profile, and thus there may be a risk that the collet profile cannot fit into the corresponding collar profile, for example , due to the large manufacturing tolerance of the collet profile and / or sleeve profile, and / or that the collet 200 will enter the sliding sleeve 106 at high speed, so there will not be enough time to return the offset collet profile to a non-offset state before the collet 200 exits. from the sliding sleeve 106.

On the other hand, if t is equal to or close to 1, the grooves and their corresponding ridges have a maximum length difference L _b , and there is a risk that the collet profile may mistakenly enter the inappropriate sleeve profile (described below).

In some embodiments, t may be sufficiently greater than zero and sufficiently less than one to ensure that:

(i) the collet profile matching the collar profile in the set did not exactly fit any other collar profile in the same set; and

(ii) the difference in lengths between the groove and its corresponding ridge (e.g., the difference in length between the sleeve groove 184A and the collet ridge 222A, the length difference between the collet groove 234 and the sleeve ridge 232, or the length difference between the sleeve groove 184B and the collet ridge 222B) was sufficient. for easy entry of the ridge into the groove.

For example, in one embodiment, t may be 0.9≥t≥0.1. In some alternative embodiments, t may be 0.8 t 0.2. In some alternative embodiments, t may be 0.7≥t≥0.3. In some alternative embodiments, t may be 0.6 t 0.4. In some alternative embodiments, t may be selected to be about 0.5.

FIG. 22 shows a set A1 of four sleeve profiles and four corresponding collet profiles, when n = 0 and K = 6, and the sleeve profiles are characterized by the same length L _s = 7L _b .

FIG. 23 shows a set B1 of six sleeve profiles and six corresponding collet profiles, when n = 0 and K = 8, the sleeve profiles having the same length L _s = 9L _b .

FIG. 24 shows a set C1 of eight sleeve profiles and eight corresponding collet profiles, when n = 0 and K = 10, and the sleeve profiles are characterized by the same length L _s = 11L _b .

FIG. 25 shows a set D1 of ten sleeve profiles and ten corresponding collet profiles, when n = 0 and K = 12, and the sleeve profiles are characterized by the same length L _s = 13L _b .

FIG. 26 shows a set A2 of three sleeve profiles and three corresponding collet profiles, when n = 1 and K = 5, and the sleeve profiles are characterized by the same length L _s = 7L _b .

FIG. 27 shows a set B2 of five sleeve profiles and five corresponding collet profiles, when n = 1 and K = 7, and the sleeve profiles are characterized by the same length L _s = 9L _b .

FIG. 28 shows a set C2 of seven sleeve profiles and seven corresponding collet profiles, when n = 1 and K = 9, the sleeve profiles having the same length L _s = 11L _b .

FIG. 29 shows a set D2 of nine sleeve profiles and nine corresponding collet profiles when n = 1 and K = 11, the sleeve profiles having the same length L _s = 13L _b .

FIG. 30 shows a set A3 of two sleeve profiles and two corresponding collet profiles, when n = 2 and K = 4, the sleeve profiles having the same length L _s = 7L _b .

FIG. 31 shows a set B3 of four sleeve profiles and four corresponding collet profiles when n = 2 and K = 6, the sleeve profiles having the same length L _s = 9L _b .

FIG. 32 shows a set C3 of six sleeve profiles and six corresponding collet profiles, when n = 2 and K = 8, the sleeve profiles having the same length L _s = 11L _b .

FIG. 33 shows a set D3 of eight sleeve profiles and eight corresponding collet profiles, when n = 2 and K = 10, the sleeve profiles having the same length L _s = 13L _b .

FIG. 34 shows a set A4 of one sleeve profile and one corresponding collet profile, when n = 3 and K = 3, and the sleeve profile is characterized by a length L _s = 7L _b .

FIG. 35 shows a set B4 of three sleeve profiles and three corresponding collet profiles, when n = 3 and K = 5, the sleeve profiles having the same length L _s = 9L _b .

FIG. 36 shows a set C4 of five sleeve profiles and five corresponding collet profiles, when n = 3 and K = 7, the sleeve profiles having the same length L _s = HL _b .

FIG. 37 shows a set D4 of seven sleeve profiles and seven corresponding collet profiles, when n = 3 and K = 9, the sleeve profiles having the same length L _s = 13L _b .

FIG. 38 shows a set B5 of two sleeve profiles and two corresponding collet profiles, when n = 4 and K = 4, and the sleeve profiles are characterized by the same length L _s = 9L _b .

FIG. 39 shows a set C5 of four sleeve profiles and four corresponding collet profiles, when n = 4 and K = 6, the sleeve profiles having the same length L _s = 11L _b .

FIG. 40 shows a set D5 of six sleeve profiles and six corresponding collet profiles, when n = 4 and K = 8, the sleeve profiles having the same length L _s = 13L _b .

FIG. 41 shows a set B6 of one sleeve profile and one corresponding collet profile, when n = 5 and K = 3, the sleeve profile having a length L _s = 9L _b .

FIG. 42 shows a set C6 of three sleeve profiles and three corresponding collet profiles, when n = 5 and K = 5, the sleeve profiles having the same length L _s = HL _b .

FIG. 43 shows a set D6 of five sleeve profiles and five corresponding collet profiles, when n = 5 and K = 7, the sleeve profiles having the same length L _s = 13L _b .

FIG. 44 shows a set C7 of two sleeve profiles and two corresponding collet profiles, when n = 6 and K = 4, the sleeve profiles having the same length L _s = 11L _b .

FIG. 45 shows a set D7 of four sleeve profiles and four corresponding collet profiles when n = 6 and K = 6, the sleeve profiles having the same length L _s = 13L _b .

FIG. 46 shows a set of C8 from one sleeve profile and one corresponding collet profile, when n = 7 and K = 3, the sleeve profile having a length L _s = 11L _b .

FIG. 47 shows a set D8 of three sleeve profiles and three corresponding collet profiles, when n = 7 and K = 5, and the sleeve profiles are characterized by the same length L _s = 13L _b .

FIG. 48 shows a set D9 of two sleeve profiles and two corresponding collet profiles, when n = 8 and K = 4, the sleeve profiles having the same length L _s = 13L _b .

FIG. 49 shows a set D8 of one sleeve profile and one corresponding collet profile, when n = 9 and K = 3, and the sleeve profile is characterized by a length L _s = 13L _b .

Table 1 below summarizes the sets of profiles shown in FIG. 22-49. As you can see, by limiting the collar profile lengths to 7L _b , 9L _b , 11L _b and 13L _b , a total of 122 collar profiles and 122 corresponding collet profiles can be obtained and used for hydraulic fracturing in the well.

In embodiments in which two or more slide valves 100 are used on the pipe string having the aforementioned coupling profiles, the order of placement of the coupling profiles is as follows:

(a) spool valves must have different coupling profiles; in other words, for any two slide valves at least one of n, K and m ₁ is different;

(b) shorter spool valves L _s should be located higher up the wellbore than longer spool valves L _s ; in other words, spool valves with smaller (n + K) are located higher up the wellbore than spool valves with larger (n + K);

(c) for spool valves of equal length L _s , those with more S _r should be located higher up the wellbore than those with less S _r ; in other words, for spool valves with the same (n + K), those with more n are located higher up the wellbore than those with less n; and

(d) spool valves having the same set of profiles, i. e. those that are characterized by the same n and the same K, but different m ₁ can be located in any order.

In other words, spool valves with the "lowest" letter of the category designation (for example, "A"), i.e. spool valves with a shorter sleeve profile L _s should be located higher up the wellbore than spool valves with a "higher" category designation letter (eg "D"), i.e. those with a shorter sleeve profile L _s . As for spool valves with the same category designation letter, i.e. characterized by the same length of the sleeve profile L _s , then those with a lower set number (for example, "A1") should be located lower along the wellbore than those with a higher set number (for example, "A3"). FIG. 50 shows an example of a tubing string (such as casing or tubing) having a plurality of slide valves 100 with the above-described arrangement.

In some alternative embodiments, if t is equal to or close to 1 and the grooves and their corresponding ridges have a maximum length difference L _b , the two “adjacent” profiles of the sleeve and collet are compatible.

That is, the collet profile can be placed not only in the corresponding sleeve profile, but also in the sleeve profile with the same category designation letter, the same set number and “adjacent” profile number (ie, 1 more or less). For example, collet profile C (A1-2), i.e. C [0, 6, 2], can be included in the previous and next profiles of the coupling S (A1-1) and S (Al-2), i.e. S [0, 6, 1] and S [0, 6, 3], but cannot be included in other coupling profiles in the set of A1 profiles, for example S (Al-4).

In other words, the collet profile can be included in the previous and next coupling profiles in the same set of profiles, but cannot be included in other coupling profiles in the same set of profiles. That is, the collet profile C [n, K, i] can be included in the coupling profiles S [n, K, i + 1] and S [n, K, i-1], but cannot be included in other coupling profiles, i.e. e. coupling profiles S [n, K, j], where j ≠ i, j ≠ i + 1 and j ≠ i-1.

Thus, in embodiments in which t = 1, and two or more spool valves 100 having clutch profiles such as those shown in FIG. 22 49 are used on a string of pipes, the order of placement of the coupling profiles should be as follows:

(a) spool valves must have different coupling profiles; in other words, for any two slide valves at least one of n, K and m ₁ is different;

(b) each set of profiles should not use two coupling profiles S [n, K, j ₁ ] and S [n, K, j ₂ ] on the same pipe string if | jj ₂ | ≤1; in other words, for any two spool valves with the same n and the same K, the difference between their m ₁ must be greater than 1;

(c) shorter spool valves L _s should be located higher up the wellbore than longer spool valves L _s ; in other words, spool valves with smaller (n + K) are located higher up the wellbore than spool valves with larger (n + K);

(d) for spool valves of equal length L _s , those with more S _r should be located higher up the wellbore than those with less S _r ; in other words, for spool valves with the same (n + K), those with more n are located higher up the wellbore than those with less η; and

(e) spool valves having the same set of profiles, i. e. those characterized by the same n and the same K, but different m ₁ , can be arranged in any order.

In some alternative embodiments, the above-described sleeve profiles and collet profiles can be connected in series or cascade with other suitable profiles to obtain elongated profiles. For example, in FIG. 51 shows a set of elongated sleeve and collet profiles obtained by sequentially placing the same profile 286 between the profile in the set of profiles A1 and the retaining ring 192. As shown in FIG. 52, in some embodiments, the same profile 286 may be positioned sequentially uphole with respect to the profiles in set A1 to obtain elongated profiles.

In some embodiments, profiles in the same set can be arranged in series with other profiles to form elongated profiles. For example, in FIG. 53 shows the profiles of set A1 in series with the first four profiles in set B2 to obtain elongated profiles.

In the above embodiments, the collar profile is on the inner surface of the collar body 152, whereby the thrust shoulder 194 of the retaining ring 192 is located downhole relative thereto. In some alternative embodiments, such as shown in FIG. 54-56, the sleeve profile comprises a part of the profile on the inner surface of the sleeve body 152, as described above, and a part of the profile on the inner surface of the sleeve 154, whereby the thrust shoulder 194 of the circlip 192 is in the sleeve profile.

Accordingly, collet 200 may have a collet profile protruding from both the sleeve body 152 and the sleeve 154 to match the profile of the sleeve. To ensure smooth passage of the front or downhole portion of the collet 200 through the stop ring 192, each protrusion 292 on the collet 200 that corresponds to the profile on the collar 154 has an obtuse angle on its downhole side.

The profile on the protective sleeve 154 may be of any suitable shape and may be combined with the sleeve body 152 of any suitable profile, such as any of those shown in FIGS. 22-49. For example, in FIG. 54-57 show a protective sleeve 154, characterized by the presence of a groove 294 of length 2L _b and combined with the sets of profiles A1, B1, C1 and D1, which are shown in FIG. 22-25 respectively. Accordingly, the profile of the collet 200 includes a ridge or ridge 292 of length L _b to match the groove 294.

In some embodiments, groove 294 may have other suitable lengths. For example, in FIG. 58-61 show a protective sleeve 154, characterized by the presence of a groove 294 of length 3L _b and combined with the sets of profiles A1, B1, C1 and D1, which are shown in FIG. 22-25 respectively. Accordingly, the profile of the collet 200 includes a ridge or ridge 292 of length 2L _b to match the groove 294.

In some embodiments, the profile on the shield 154 may include one or more grooves and / or one or more ridges.

In some embodiments, the profile on the protective sleeve 154 may be a profile selected from those shown in FIGS. 22-49. For example, a set of elongated profiles can be obtained by sequentially placing the profiles in the set of A1 with the first four profiles in the set of B2, with the first four profiles in the set of B2 located downhole relative to the retaining ring 192 or on the protective sleeve 154.

As shown in FIG. 62, in some alternative embodiments, the collar profile (such as the collar profile in set of profiles A1) may be located downhole with respect to retaining ring 192. Thus, thrust shoulder 194 is located uphole with respect to the collar profile. In these embodiments, each protrusion on the collet 200 has an obtuse angle on its downhole side to allow the collet 200 to smoothly pass through the retaining ring 192.

As described above and shown in FIG. 15A and 15B, slide sleeve 126 of spool valve 100 can be pressure actuated by ball 242 and collet 200 to an open position to expose fracturing fluid ports, and petals 218 of collet 200 can be pressure driven to expand radially outward when the uphole fluid pressure is applied and the collet is compressed when the collet profile 212 engages the shoulder 194 of the retaining ring 192, causing the blades 218 to expand radially outward to further engage the sliding sleeve 106 to enhance engagement and increase resistance pressure. FIG. 63A-63F show in more detail the radially outward expanding collet profile 212.

As shown in FIG. 63A, for ease of description, clutch grooves 184A and 184B are assumed to have the same ID, and collet ridges 222A and 222B are assumed to have the same OD.

The depth H _{sg1 of the} up-hole sleeve groove 184A is measured radially between its outermost surface (i.e., its "bottom") and its innermost up-borehole edge (i.e., its up-hole " upper "edge). The height H _sr of the clutch ridge 232 is measured radially between its innermost surface (ie, its “top”) and its outermost edge (ie, its “bottom” edge). The depth H _{sg2 of the collar} groove 184B downhole is measured radially between its outermost surface and its innermost downhole edge, which is also the innermost edge of the thrust shoulder 194.

Similarly, the height H _cr1 located uphole ridges 222A collet is measured between their radially outermost surface (i.e., their "top") and the innermost positioned uphole edge (i.e., their location uphole wells "bottom" edge). The depth H _{cg of the} collet groove 234 is measured radially between its innermost surface (ie, its “bottom”) and its outermost edge (ie, its “top” edge). _{Collet heights} H cr2 downhole ridges 222 B are measured radially between their outermost surface (ie, their "top") and their innermost downhole edge (ie, their downhole "Bottom" edge).

In some embodiments shown in FIG. 63A-3C, H _cg1 = H _sg2 = H _sr = H _s and H _cr1 = H _cr2 = H _cr . As shown in FIG. 63B, so that the collet profile 212 can expand radially outward as the collet profile 212 engages with the collar profile 182, it is necessary to maintain clearance between each of the collar grooves 184A and 184B and the collet groove 234 and each of the respective collet ridges 222A and 222B. and a clutch flange 232. In other words, H _s -H _cr > 0, H _cg -H _cr > 0 and ε ₂ > 0. Thus, according to these embodiments, H _s > H _cr , H _cg > H _cr, and ε ₂ > 0.

According to some embodiments in which H _sg1 = H _sg2 = H _sr = H _s and H _cr1 = H _cr2 = H _cr and the collet groove 234 is located around the longitudinal center of the collet profile 212, the collet groove 234 is the widest portion when the petals 218 expands or flexes radially outward (see FIG. 63C). In these embodiments, H _s > H _cr , H _cg > H _cr, and ε ₂ > 0 are required. Preferably, the clearance between the collet groove 232 and the clutch flange 232 is greater than or equal to the clearance between the clutch groove 184A / 184B and the corresponding collet flange 222A / 222B. In other words, H _s -H _cr > 0, H _cg -H _cr > 0, H _cg -H _cr ≥H _s -H _cr and ε ₂ > 0. Thus, according to these embodiments, H _cg > H _s > H _cr and ε ₂ > 0. In some embodiments, it is preferred that H _cg = H _s > H _cr and ε ₂ > 0 so that when the collet profile 212 expands radially outward in the clutch profile 182, the collet ridge 234 can fully engage with the collar ridge 232 and clearance between them is excluded.

As shown in FIG. 63B and 63C, after collet 200 engages sliding sleeve 106, additional pressure from a position upbore may move collet 200 downhole, causing the petals 218 to expand or flex radially outward, and additionally and to a greater extent. engage in mating engagement with the sliding sleeve 106.

In some embodiments shown in FIG. 63D-63F, the depth of the uphole collar groove 184A is the same as the height of the collar ridge 232. However, the downhole collar groove 184B has a depth that is greater than the depth of the upbore collar groove 184A. That is, H _sg1 = H _sr = H _s and H _sg2 > H _s . The heights of the collet flanges 222A and 222B and the depth of the collet groove 234 are the same. That is, H _cr1 = H _cr2 = H _cr .

As shown in FIG. 63E, according to these embodiments, H _cd + H _sg2 -H _cr- H _s > 0, H _sg2 -H _cr > 0, and ε ₂ > 0 so that the collet profile 212 can expand radially outward when the collet profile 212 engages profile 182 of the coupling.

According to some embodiments in which H _sgl = H _sr = H _s , H _sg2 > H _s , H _cr1 = H _cr2 = H _cr , and the collet groove 234 is located around the longitudinal center of the collet profile 212, the collet groove 234 is the widest part when the petals 218 expand radially outward (see FIG. 63E).

In these embodiments, H _cg + H _sg2 —H _cr —H _s > 0, H _sg2 —H _cr > 0, and ε ₂ > 0. Preferably, the clearance between the collet groove 232 and the clutch flange 232 is greater than or equal to the clearance between the clutch groove 184A / 184B and the corresponding collet flange 222A / 222B. In other words, H _cg + H _sg2 -H _cr -H _s ≥H _sg2 -H _cr. Thus, according to these embodiments, H _sg2 > H _cr , H _cg ≥ _{H s,} and ε ₂ > 0. In some embodiments, it is preferred that H _sg2 > H _cr , H _cg = H _s, and ε ₂ > 0 so that when the collet profile 212 expands radially outward in the sleeve profile 182, the collet ridge 234 can fully engage with the ridge 232 couplings and the gap between them is excluded.

Although the embodiments have been described above with reference to the accompanying figures, it will be apparent to those skilled in the art that variations and modifications may be made therein without departing from the scope of the present invention.

For a complete definition of the present invention and its scope, reference should be made to the Summary of the Invention and the appended claims, set forth and considered in conjunction with the detailed description and drawings provided herein, for their purposeful interpretation.

Claims (60)

1. A spool valve for opening one or more openings for a fluid in a pipe string, comprising: a valve body having a longitudinal bore, the valve body comprising said one or more fluid openings on an up-wellbore portion of its sidewall; a collet element having a corresponding locking profile; and a sliding sleeve that is slidably positioned in the longitudinal bore of the valve body and is movable between an up-borehole closed position in which one or more fluid openings are closed, and a down-borehole open position in which one or more fluid openings are open; moreover, the sliding sleeve contains: the longitudinal channel and the profile of the sleeve thereon to accommodate the corresponding retaining profile of the collet element; and a retaining ring having on the lateral edge located above the wellbore a stop shoulder configured to abut against a part of the corresponding retaining profile of the collet element when said corresponding retaining profile thereof engages with the specified profile of the coupling and prevents the collet element from moving down the wellbore relative to sliding clutch. 2. A spool valve according to claim 1, wherein at least said stop shoulder of said retaining ring has a hardness that is greater than that of the sliding sleeve material, or it comprises a material having a hardness that is greater than that of the sliding sleeve. 3. A spool valve according to claim 1, wherein said retaining ring is comprised of a material having a hardness that is greater than the material of the sliding sleeve. 4. A spool valve according to claim 1, wherein at least said stop shoulder of said stop ring is comprised of a material selected from the group of materials including tungsten carbide, cobalt-chromium alloys, and nitrided steels, or combinations thereof. 5. The spool valve according to any one of paragraphs. 1-4, wherein said sleeve profile on said sliding sleeve is located higher up the wellbore relative to the retaining ring. 6. The spool valve according to any one of paragraphs. 1-5, in which the thrust shoulder forms an acute angle relative to the longitudinal axis of the spool valve, whereby the inner edge of the said thrust shoulder is located higher along the wellbore than the outer edge of the said thrust shoulder. 7. The spool valve according to any one of paragraphs. 1-6, in which the sliding sleeve further down the wellbore with respect to said retaining ring further comprises a connecting portion; and the specified sliding sleeve further comprises a protective sleeve, and located above the borehole end of the specified protective sleeve is connected to the specified connection part, the specified protective sleeve extends down the wellbore; and moreover, the retaining ring is an annular element; and wherein the sliding sleeve further comprises a retaining ring seat for positioning the retaining ring between the retaining ring seat and an up-wellbore end of the protective sleeve. 8. A spool valve according to claim 7, wherein the protective sleeve defines an annular space between a portion of its outer periphery and said valve body when the sliding sleeve is in a closed position; and moreover, the protective sleeve isolates the annular space from the second channel. 9. A spool valve for opening one or more openings for a fluid in a production string, comprising: a valve body having a longitudinal bore, the valve body comprising one or more fluid openings on an up-wellbore portion of its sidewall; a sliding sleeve having a longitudinal bore and a sleeve profile thereon, wherein the sliding sleeve is slidably disposed in the longitudinal bore of the valve body and is movable between an up-wellbore closed position in which one or more fluid openings are closed, and a downhole open position in which one or more fluid openings are open; and a collet element configured to be placed in a longitudinal channel of a sliding sleeve having a corresponding locking profile, said corresponding locking profile being adapted to mate with said sleeve profile; moreover, the sliding sleeve additionally contains: a stop ring defining a first stop shoulder that prevents the collet member from moving downhole relative to the sliding sleeve when said respective retaining profile of said collet member engages in mating engagement with said sleeve profile of said sleeve member. 10. A spool valve according to claim 9, wherein at least said abutment shoulder of said retaining ring has a hardness that is greater than that of the sliding sleeve material, or it comprises a material having a hardness that is greater than that of the sliding sleeve. 11. A spool valve according to claim 9, wherein said retaining ring is comprised of a material having a hardness that is greater than that of the sliding sleeve material. 12. The spool valve according to any one of paragraphs. 9-11, in which at least the specified stop shoulder of the specified stop ring is given a hardness equal to the hardness located down the wellbore part of the corresponding fixing profile of the specified collet element. 13. The spool valve according to any one of paragraphs. 9-11, in which the stop collar is composed of a material having a hardness approximately equal to that of the downhole portion of the corresponding retaining profile of said collet element. 14. The spool valve of claim 9, wherein at least said stop shoulder of said stop ring is comprised of a material selected from the group of materials including tungsten carbide, cobalt-chromium alloys, and nitrided steels, or combinations thereof. 15. The spool valve according to any one of paragraphs. 9-14, wherein said sleeve profile on said sliding sleeve is located higher up the wellbore relative to the retaining ring. 16. The spool valve according to any one of paragraphs. 9-15, in which the thrust shoulder forms an acute angle relative to the longitudinal axis of the spool valve, as a result of which the inner edge of the said thrust shoulder is located higher along the wellbore than the outer edge of the said thrust shoulder. 17. The spool valve according to any one of paragraphs. 9-16, in which the sliding sleeve downhole with respect to the specified retaining ring further comprises a connecting portion; and the specified sliding sleeve further comprises a protective sleeve, and located above the borehole end of the specified protective sleeve is connected to the specified connection part, the specified protective sleeve extends down the wellbore; and moreover, the retaining ring is an annular element; and The sliding sleeve further comprises a retaining ring seat for positioning the retaining ring between the retaining ring seat and the end of the protective sleeve located upstream of the wellbore. 18. A spool valve according to claim 17, wherein the protective sleeve defines an annular space between a portion of its outer periphery and said valve body when the sliding sleeve is in a closed position; and moreover, the protective sleeve isolates the annular space from the second channel. 19. The spool valve according to any one of paragraphs. 9-18, wherein said respective collet retaining profile comprises a stop shoulder at its downhole end for engaging with the stop ring stop shoulder. 20. A spool valve according to claim 19, dependent on claim 16, in which the thrust shoulder on said collet element forms an acute angle relative to the longitudinal axis of the spool valve, as a result of which the inner edge of said thrust shoulder on said collet element is located higher along the wellbore than the outer edge of the specified thrust shoulder on the specified collet element. 21. A spool valve according to claim 9, wherein the corresponding retaining profile of said collet element is a radially flexible collet profile configured to mate with said sleeve profile on said sliding sleeve. 22. A spool valve according to claim 9, wherein the collet element further comprises a cylindrical up-borehole portion, a cylindrical down-borehole portion, and a plurality of flexible petals therebetween, connected to an up-borehole and down-borehole parts, on said flexible petals there is a specified corresponding fixing profile. 23. A spool valve for opening one or more openings for a fluid in a production string, comprising: a valve body having a longitudinal bore, the valve body comprising said one or more fluid openings on an up-wellbore portion of its sidewall; and a sliding sleeve disposed in the longitudinal bore of the valve body and configured to move between an up-borehole closed position in which one or more fluid openings are closed, and a down-borehole open position in which one or more fluid openings fluid open; moreover, the sliding sleeve contains: - a sleeve body having a longitudinal channel, the sleeve body having in said longitudinal channel a profiled region containing at least two grooves and a ridge between them; - a collet in the longitudinal channel of the sliding sleeve, additionally having a profiled region corresponding to the sleeve, containing corresponding ridges and a corresponding groove, and in order to ensure that the profiled regions are adapted for appropriate engagement with each other, the groove width on either of the two profiled regions must be equal to or greater than the width of the corresponding ridge on the other of the two profiled regions to accommodate the corresponding ridge therein; and - a protective sleeve located below the wellbore relative to the sleeve body; and moreover, at least the connecting part of the protective sleeve is located in the sleeve body for connecting the protective sleeve to the sleeve body; moreover, at least when the sliding sleeve is in the closed position, an annular space is formed between the protective sleeve and the valve body; and wherein the protective sleeve isolates the annular space from the longitudinal channel of the valve body, and wherein the sliding sleeve further comprises, at its downhole end, a stop ring having a stop shoulder to prevent said collet from moving down the wellbore in the longitudinal channel of the sliding sleeve when it is in mating engagement with said sliding sleeve. 24. A spool valve according to claim 23, wherein the thrust shoulder has a first acute angle relative to the longitudinal axis of the slide valve, whereby the inner edge of said thrust shoulder is located higher up the wellbore than the outer edge of said thrust shoulder. 25. A spool valve according to claim 23 or 24, wherein the stop shoulder is formed by a retaining ring housed in the sliding sleeve. 26. The spool valve of claim 23, wherein the sleeve housing comprises a retaining ring seat for positioning the retaining ring between the retaining ring seat and an uphole end of the protective sleeve. 27. The spool valve according to any one of paragraphs. 23-26, in which at least the specified stop shoulder is given a hardness that is greater than the hardness of the material of the sliding sleeve, or it contains a material characterized by a hardness that is greater than the hardness of the sliding sleeve. 28. A spool valve according to claim 25, wherein said retaining ring is comprised of a material having a hardness that is greater than that of the sliding sleeve. 29. The spool valve according to any one of paragraphs. 23-28, in which at least the specified stop shoulder is given a hardness approximately equal to the hardness of the corresponding profiled region of the collet. 30. The spool valve according to any one of paragraphs. 23-28, wherein the corresponding collet profiled region has a downhole portion thereon, and wherein the thrust shoulder is composed of a material having a hardness approximately equal to the downhole portion of the corresponding collet profiled region.

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