SLEEVE VALVES

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser. No. 63/671,865 filed on Jul. 16, 2024, entitled “SLEEVE VALVES” and incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to downhole tools for wellbore operations. More specifically, the present disclosure relates to sleeve valves which are opened and closed by bottom hole assemblies.

BACKGROUND

Sleeve valve apparatuses in a casing string may be used for opening and closing ports at multiple positions along the casing string. A given sleeve valve apparatus (which may simply be referred to as a “sleeve valve” herein) may comprise a tubular housing with one or more ports and an axially shiftable inner sleeve that is shiftable between opened and closed positions. In the closed position, the inner sleeve covers and blocks fluid flow through the one or more ports, and in the opened position the inner sleeve does not cover the one or more ports. The sleeve valves are typically spaced along casing, for permitting the flow of fluids through ports when the inner sleeve is shifted axially to expose ports in the housing or to block the flow of fluids therethrough when the sleeve covers the ports. Shifting tools are used for shifting the inner sleeve in a single shift operation to an open position, or can be manipulated to both open and to close in a multi-cycle operation. The sleeve valves may be configured to be opened by shifting the inner sleeve up. Alternatively, the sleeve valves may be configured to open by shifting the inner sleeve down.

A bottom hole assembly (BHA) may be run downhole to engage and open/close sleeve assemblies. The BHA may include a shifting tool and equipment for use in a downhole fracturing operation. The BHA may be connected to the downhole end of coiled tubing, for example. A shifting tool may sequentially manipulate numerous sleeve valves (cemented or uncemented) spaced along a casing string extending downhole for fracturing in an oil or gas well (vertical, deviated or horizontal). Open-only sleeve valves are typically operated in a toe-to-heel treatment and, for each treatment, a releasable packer can be positioned to isolate each treated zone below from the next uphole zone above.

There are several challenges or drawbacks of existing sleeve valve apparatuses. Some systems include a sleeve locator and a resettable plug (packer) or other isolator element to grip the inner sleeve and fill the annulus to allow hydraulic movement of the sleeve by building pressure above the plug. However, in such systems, the inner sleeve must have sufficient length to accommodate both the locator and the plug. Heavy sleeves are more difficult to manage, even requiring the implementation of additional equipment simply for handling during makeup of the string.

Casing manufacturers routinely install casing collars on every joint of casing in an automated process. However, additional length translates into additional material and manufacturing complexity and cost. In addition, long sleeves cannot replace casing collars in the automated process, are difficult to handle manually, and would necessitate modifications of the assembly equipment at the casing plant, which is expensive and time consuming.

SUMMARY

The present disclosure provides embodiments of sleeve valves which are shifted between open/closed positions in a casing string by any suitable bottom hole assembly comprising a shifting assembly. The sleeve valves described herein may provide several advantages over existing (prior art) shiftable sleeve valves.

Some embodiments of the sleeve valves disclosed herein are compact and lightweight. Some embodiments of the sleeve valves have an overall length of less than about 22 inches. Smaller sleeve valves may be more material and cost efficient. Smaller sleeve valves may also be more manageable when assembling the casing string.

Some embodiments of the sleeve valves include friction rings which provide several advantages including, but not limited to, (1) providing consistent drag force for the inner sleeve; (2) providing scraping/wiping action against the inner surface of the housing to protect sealing elements from cement, scale, debris, etc.; (3) acting as a buffer seal; (4) acting as a secondary or back-up mechanical seal if other sealing elements are compromised; (5) providing a damping effect; and (6) securing the inner sleeve in any desired position (not simply open and closed) within the housing.

Some embodiments of the sleeve valves include options for attaching the friction rings to the inner sleeve selected from either a single, dual, or multiple barb engagement, or a retaining ring.

Some embodiments of the sleeve valves include sealing elements.

Some embodiments of the sleeve valves include options for connectors (either box-pin or box-box configuration), thereby permitting factory installation on casing.

Some embodiments of the sleeve valve (due to its short length) including the “box-box” configuration may be attached directly to a casing section by a casing manufacturer in place of a traditional casing coupler, thereby saving material, time, and expense. As a result of the shortened length, the sleeve valves may be used to couple sections of casing to replace conventional couplers or collars, and without requiring modifications to the carousel. Consequently, the overall cost may be lower than would be the case where both casing couplers and sleeve assemblies are used separately therein.

Those skilled in the art will recognize that a standard stage is typically defined as five seal points, three threads, and two engineered precision seals. The “box-to-box” configuration may eliminate one threaded connection at every stage. Considering a well with one hundred stages for example, elimination of one threaded connection at each stage may reduce the tubular stiffness, rendering the liner more pliable to run into the well; reduce the drilling rig make up time at every stage; and eliminate transport and storage logistics and costs.

Some embodiments of the sleeve valves may be either shift-up-to-open sleeve valves or shift-down-to-open sleeve valves. The sleeve valves may be engaged and shifted by hydraulically actuated components of the shifting assembly of a suitable bottom hole assembly. The terms “hydraulically actuated” or “hydraulically activated” as used herein may refer to tools or components that may be actuated by fluid pressure and/or flow.

Various example aspects and embodiments of the disclosure are set out in the following description and claims.

Broadly, in one aspect, a sleeve valve for use in a casing string in a treatment zone or formation comprises:

• • a tubular housing defining a housing bore and one or more housing ports;
  • an inner sleeve comprising friction rings in sliding frictional and fluid sealing engagement with the housing,
  • the inner sleeve being axially shiftable within the housing between a closed sleeve position wherein the one or more ports are obstructed, and an open sleeve position wherein the one or more ports are unobstructed, thereby allowing fluid flow from the housing bore to the treatment zone or the formation and production.

In another aspect, a system for use in a casing string in a treatment zone or formation comprises:

• • a first casing section comprising a first pin end;
  • a second casing section comprising either internal threads or a second pin end;
  • a sleeve assembly comprising:
    • a tubular housing defining a housing bore and one or more housing ports;
  • an inner sleeve comprising friction rings in sliding frictional and fluid sealing engagement with the housing,
    • the inner sleeve being axially shiftable within the housing between a closed sleeve position wherein the one or more ports are obstructed, and an open sleeve position wherein the one or more ports are unobstructed, thereby allowing fluid flow from the housing bore to the treatment zone or the formation and production.

In yet another aspect, a method for fracturing comprises:

• • providing a casing string without packers in a treatment zone or formation, wherein the casing string comprises a plurality of sleeve valves,
    • each sleeve valve comprising a tubular housing defining a housing bore and one or more housing ports; an inner sleeve comprising sealing elements secured about the inner sleeve and friction rings in sliding frictional and fluid sealing engagement with the housing, the inner sleeve being axially shiftable within the housing between a closed sleeve position wherein the one or more ports are obstructed, and an open sleeve position wherein the one or more ports are unobstructed, thereby allowing fluid flow from the housing bore to the treatment zone or the formation and production;
  • opening a first sleeve valve in a first wellbore zone, with other sleeve valves being closed with the sealing elements of the other sleeve valves effectively sealing and the friction rings as back-up in event of failure of the sealing elements;
  • in a first fracturing step, pumping fracturing fluid through the first sleeve valve to the treatment zone or the formation to form one or more fractures therethrough;
  • closing the first sleeve valve after completion of the first fracturing step;
  • opening a second sleeve valve in a second wellbore zone, with the first and other sleeve valves being closed with the sealing elements of the first and other sleeve valves effectively sealing and the friction rings as back-up in event of failure of the sealing elements;
  • in a second fracturing step, pumping additional fracturing fluid through the second sleeve valve to the treatment zone or the formation to form one or more fractures therethrough;
  • closing the second sleeve valve after completion of the second fracturing step; and repeating opening, fracturing, and closing steps sequentially for one or more of the other sleeve valves.

Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of the specific embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be better understood having regard to the drawings in which:

FIG. 1 is a side view diagram of an example wellbore system in which embodiments of the present disclosure may be implemented;

FIG. 2 is a side view of an example BHA that may provide efficient and effective sleeve shifting and isolation functionality;

FIG. 3A is a side view of a first embodiment of a sleeve valve;

FIG. 3B is an exploded view of the sleeve valve of FIG. 3A;

FIG. 3C is a side cross-sectional view of the sleeve valve of FIG. 3A in a closed sleeve position;

FIG. 3D is a side cross-sectional view of the sleeve valve of FIG. 3A in an opened sleeve position.

FIG. 3E is an enlarged side cross-sectional partial view of the sleeve valve of FIG. 3A, showing additional details of components thereof;

FIG. 3F is an enlarged side cross-sectional partial view of the sleeve valve of FIG. 3E, showing additional details of components thereof;

FIG. 4A is a side view of a second embodiment of a sleeve valve;

FIG. 4B is a side cross-sectional view of the sleeve valve of FIG. 4A in a closed sleeve position;

FIG. 4C is a side cross-sectional view of the sleeve valve of FIG. 4A in an opened sleeve position;

FIG. 5A is a side view of a third embodiment of a sleeve valve;

FIG. 5B is a side cross-sectional view of the sleeve valve of FIG. 5A in a closed sleeve position;

FIG. 5C is a side cross-sectional view of the sleeve valve of FIG. 5A in an opened sleeve position;

FIG. 6A is a side cross-sectional view of a fourth embodiment of a sleeve valve in a closed sleeve position.

FIG. 6B is an enlarged side cross-sectional partial view of the sleeve valve of FIG. 6A, showing additional details of components thereof.

FIG. 7A is a side view of a fifth embodiment of a sleeve valve;

FIG. 7B is a side cross-sectional view of the sleeve valve of FIG. 7A in an opened sleeve position.

DETAILED DESCRIPTION

FIG. 1 is a side view diagram of an example wellbore system 100 in which embodiments of the present disclosure may be implemented. The system 100 includes surface equipment 102 and a drilled well 103 in formation 104. The well includes a horizontal section 105. The well has a casing string 106 installed therein (within the wellbore). The casing string 106 may include a plurality of interconnected casing sections and, in this example, includes a plurality of sleeve valves 107 spaced apart within the horizontal section 105.

The surface equipment 102 may include a rig with equipment raising and lowering a BHA attached to coiled tubing within the well. The surface equipment 102 may further include one or more fluid pumps for pumping fluid(s) through the coiled tubing into the BHA and/or into the annulus within the casing string 106.

A fracturing operation may include: opening one of the sleeve valves 107 using a shifting tool run downhole; isolating a wellbore zone about the sleeve valve 107; and pumping fracturing fluid at pressures sufficiently high for the fracturing fluid to exit through ports of the sleeve valve 107 and fracture the formation 104 in the region of the sleeve valve 107. The sleeve valve 107 may optionally be closed after the fracturing has been performed. This process may then be sequentially repeated for one or more of the remaining sleeve valves 107. The skilled person will appreciate that a fracturing operation may vary from the steps described above. In some embodiments, isolating a wellbore zone about the sleeve valve 107 may involve using one or more isolating tools such as packers. In some embodiments, the fracturing operation may be packerless, eliminating the need for packers, and isolation involves use of elastomer seals and frictions ring as back-up seals. Embodiments are not limited to a particular number, arrangement of, and/or order of opening/closing of sleeve valves 107 to name a few examples of possible variations.

FIG. 2 is a side view of an example BHA 200 according to some embodiments that may provide efficient and effective sleeve shifting and isolation functionality. Examples of BHAs are described in U.S. Provisional Patent Application No. 63/472,735 and U.S. patent application Ser. No. 18/742,452, both of which are incorporated by reference herein in their entireties. The BHA 200 in this embodiment includes: a selector valve 202; a locator sub 204 positioned downhole of the selector valve 202; a hydraulic stroker 206 positioned downhole of the locator sub 204; an anchor or “hold down” sub 208 positioned downhole of the hydraulic stroker 206; an equalization valve 210 (e.g., bypass valve) and a resettable packer 212 positioned downhole of the anchor sub 208; a J-slot mechanism 214 positioned downhole of the resettable packer 212; and a drag block 216 proximate a downhole end 217 of the BHA 200. Embodiments are not limited to the particular set of system components or their arrangement shown in FIG. 2.

The locator sub 204, hydraulic stroker 206 and the anchor sub 208 collectively function as a hydraulically actuated shifting assembly 205 (or tool) for engaging and shifting sleeve valves 107 open and/or closed. The hydraulically actuated shifting assembly 205 may allow for locating and opening/closing a sleeve valve 107 with fewer cycles of coiled tubing movement than conventional systems.

The BHA 200 in this example further includes optional components that may be omitted in other embodiments, including a coil connector 218, at the uphold end 219 of the BHA 200, for connecting the BHA 200 to coiled tubing (not shown). Optional disconnect 220 is also included intermediate the selector valve 202 and the coil connector 218. The disconnect 220 may be used to disconnect the bulk of the BHA 200 from the coiled tubing should the need arise. The BHA 200 in this example optionally also includes check valves 222 intermediate the coil connector 218 and the disconnect 220. The check valves may allow fluid flow in the downhole direction and prevent fluid flow in the uphole direction in the coiled tubing. However, the BHA 200 of FIG. 2 may be used for both shift-up-to-open and shift-down-to-open sleeve valve configurations. In some embodiments, the BHA 200 does not include the resettable packer 212, and isolation involves use of elastomer seals and friction rings as back-up seals, as will be described herein.

The present invention relates to various embodiments of sleeve valves 107 that may be operated (i.e., opened/closed) by the BHA 200 or any other suitable BHA, with reference to FIGS. 3A to 7B. Some embodiments of the sleeve valves have an overall length of less than about 22 inches.

FIGS. 3A-F are views of a first embodiment of a sleeve valve 300. The sleeve valve 300 is shown assembled in FIG. 3A and unassembled in FIG. 3B to show all its components in detail. FIG. 3C is a side cross-sectional view of the sleeve valve 300 in a closed configuration. FIG. 3D is a side cross-sectional view of the sleeve valve 300 in an opened configuration. FIGS. 3E-F are enlarged side cross-sectional partial views of the sleeve valve 300, showing additional details of components thereof.

The sleeve valve 300 comprises a tubular housing 302 having an inner surface 304 and an outer surface 306 and defining a bore 308 extending axially therethrough. During manufacture, the sleeve valve 300 may be treated with QPQ liquid nitriding for producing a housing 302 which is erosion and corrosion resistant. The housing 302 defines one or more housing ports 310 from the inner surface 304 to the outer surface 306. The one or more housing ports 310 are arranged and aligned circumferentially about the housing 302. In this embodiment, the one or more housing ports 310 are positioned at the uphole end 311. The one or more housing ports 310 are for allowing fluid, such as fracturing fluid or water, to flow from the bore 308 to a surrounding treatment zone or formation 104.

The sleeve valve 300 comprises an inner sleeve 312 that is axially shiftable within the housing 302 between a closed sleeve position (FIG. 3C) where the one or more ports 310 are obstructed by the inner sleeve 312, and an open sleeve position (FIG. 3D) where the inner sleeve 312 does not obstruct the one or more ports 310. As used herein, the phrase “obstructed by the inner sleeve” and the related terms “obstructs” and “obstructing” refers to the one or more housing ports 310 being blocked or substantially blocked such that fluid communication between the bore 308 and the surrounding environment such as, for example, the surrounding treatment area, is prevented or substantially prevented. Conversely, “does not obstruct the one or more housing ports 310” and the related expression “not obstructed” as used herein refers to fluid communication between the bore 308 and surrounding environment being permitted through the one or more housing ports 310. It will be appreciated that prevention or blocking of fluid communication between the bore 308 and the surrounding treatment area through the one or more housing ports 310 may be desirable when the inner sleeve 312 is in the closed sleeve position.

As shown in FIGS. 3C and 3D, the inner surface of the inner sleeve 312 defines a tool-engaging profile 314. In this embodiment, the tool-engaging profile 314 includes annular grooves 316a, 316b, an annular rib 318, first tapered shoulders 320a, 320b, and second tapered shoulders 322a, 322b. The annular rib 318 is positioned between the second tapered shoulders 322a, 322b. In some embodiments, the annular rib 318 is narrower than the annular grooves 316a, 316b. The second tapered shoulders 322a, 322b are positioned between the annular grooves 316a, 316b.

The tool-engaging profile 314 is shaped for engaging with the locator sub 204 (FIG. 2) such that the inner sleeve 312 can be shifted between the opened or closed sleeve positions. The sleeve valve 300 is configured for “shift-down-to-open” operation, meaning that the closed position of the inner sleeve 312 is at an uphole extent of the axial movement of the inner sleeve 312 (FIG. 3C), and the opened sleeve position of the inner sleeve 312 is at a downhole extent of the axial movement of the inner sleeve 312 (FIG. 3D) at the downhole end 313.

The sleeve valve 300 includes a detent mechanism that biases the inner sleeve 312 to remain in each of the open sleeve position and the closed sleeve position. The detent mechanism includes a pair of friction rings 324a, 324b secured about the inner sleeve 312 and annular detent grooves 326a, 326b defined in the inner surface 304 of the housing 302 for receiving the friction rings 324a, 324b therein (FIGS. 3E-F). In some embodiments, the friction rings 324a, 324b may be formed of any suitable materials including, but not limited to, metal such as, for example, aluminum bronze. Aluminum bronze has high strength, corrosion resistance, and suitability for demanding applications, including those in the downhole environment. Being formed from metal, the friction rings 324a, 324b are more robust in withstanding harsh downhole environments than elastomer seals formed of rubber or polymers which may have temperature limits or may be incompatible with certain fluids. The friction rings 324a, 324b can thus serve as secondary or back-up seals to the elastomer seals in both fracking and packerless fracking operations. Without being bound by any theory, the friction rings 324a, 324b may not completely seal 100%, but may reasonably and effectively seal about 99% or close to a complete seal. The annular detent grooves 326a, 326b define barb surfaces 328a, 328b configured to catch corresponding latch surfaces 330a, 330b of the friction rings 324a, 324b, thereby engaging the friction rings 324a, 324b and the inner sleeve 312 to one another (FIGS. 3E-F).

Without being bound by any theory, during shifting of the inner sleeve 312, the friction rings 324a, 324b may (1) provide consistent drag force for the inner sleeve 312; (2) provide scraping/wiping action against the inner surface 304 of the housing 302 to protect the sealing elements 332a, 332b from cement, scale, debris, etc.; (3) act as a buffer seal; (4) act as a secondary or back-up mechanical seal if the sealing elements 332a, 332b are compromised; (5) provide a damping effect; and (6) secure the inner sleeve 312 in any desired position (not simply open and closed) within the housing 302. The friction rings 324a, 324b provide not only different primary purposes (items 1-3 and 5-6) compared to the sealing elements 332a, 332b, but also a secondary purpose (item 4) similar to that of the sealing elements 332a, 332b.

The sleeve valve 300 further includes a pair of sealing elements 332a, 332b secured about the inner sleeve 312 and annular seal grooves 334a, 334b defined in the inner surface 304 of the housing 302. In some embodiments, each sealing element 332a, 332b is an “S”-seal comprising an elastomeric seal body 336a and integrated anti-extrusion spiral springs 338a, 338b (FIG. 3F). The “S”-seal may exhibit high pressure (bi-directional) and temperature resilience, and simplify fitting. In some embodiments, the “S”-seal may withstand pressures up to about 15 ksi.

The housing 302 also defines upper and lower inner annular shoulders 340a, 340b in the bore 308, which provide upper and lower stops for the inner sleeve 312.

The sleeve valve 300 further includes top and bottom threaded connectors 342a, 342b for coupling the sleeve valve 300 to the casing. In some embodiments, the top and bottom threaded connectors 342a, 342b form a “box-pin” configuration (FIGS. 3A, 4A, 6A, 7A). In some embodiments, the top threaded connector 342a comprises an adapter which is shorter in length (commonly known as a “pup adapter”) than the housing 302. The adapter includes internal threads 344 for connecting to complementary threads of the casing, and external threads 346 for connecting to complementary internal threads 348 of the housing 302. The housing 302 defines corresponding external threads 350 for connecting to the casing at the downhole end 313. Adapters are well known in the art as pressure-containing parts having end connections of different nominal sizes and/or pressure ratings, used to connect other parts of equipment of different nominal sizes and/or pressure ratings.

When the top threaded connector 342a and housing 302 are threadably connected, seal elements positioned therebetween are deformed radially outward and seal against the inner surface 304 of the housing 302. The seal elements are annular and formed of deformable, resilient material including, but not limited to, nitrile rubber. In some embodiments, the seal elements comprise a pair of O-rings 352a, 352b and a central ring 354 positioned between the O-rings 352a, 352b to serve as a back-up in the event of O-ring failure and seal leakage (FIG. 3B).

Various indicia or labels 356 may be provided or attached to the housing 302 including for example, certification stickers, notice labels, warning labels, manufacturing labels, and the like.

FIGS. 4A-C are views of a second embodiment of a sleeve valve 400. The sleeve valve 400 is shown assembled in FIG. 4A. FIG. 4B is a side cross-sectional view of the sleeve valve 400 in a closed configuration. FIG. 4C is a side cross-sectional view of the sleeve valve 400 in an opened configuration. The sleeve valve 400 includes the same features as the sleeve valve 300, with the exception that the sleeve valve 400 is configured for “shift-up-to-open” operation, as further described.

The sleeve valve 400 comprises a tubular housing 402 having an inner surface 404 and an outer surface 406 and defining a bore 408 extending axially therethrough. The housing 402 defines one or more housing ports 410 from the inner surface 404 to the outer surface 406. The one or more housing ports 410 are arranged and aligned circumferentially about the housing 402. In this embodiment, the one or more housing ports 410 are positioned at the downhole end 413.

The sleeve valve 400 comprises an inner sleeve 412 that is axially shiftable within the housing 402 between a closed sleeve position (FIG. 4B) where the one or more ports 410 are obstructed by the inner sleeve 412, and an open sleeve position (FIG. 4C) where the inner sleeve 412 does not obstruct the one or more ports 410.

The inner surface of the inner sleeve 412 defines a tool-engaging profile 414 (FIGS. 4B-C). In this embodiment, the tool-engaging profile 414 includes annular grooves 416a, 416b, an annular rib 418, first tapered shoulders 420a, 420b, and second tapered shoulders 422a, 422b. The annular rib 418 is positioned between the second tapered shoulders 422a, 422b. In some embodiments, the annular rib 418 is narrower than the annular grooves 416a, 416b. The second tapered shoulders 422a, 422b are positioned between the annular grooves 416a, 416b.

The tool-engaging profile 414 is shaped for engaging with the locator sub 204 (FIG. 2) such that the inner sleeve 412 can be shifted between the opened or closed sleeve positions. The sleeve valve 400 is configured for “shift-up-to-open” operation, meaning that the closed position of the inner sleeve 412 is at a downhole extent of the axial movement of the inner sleeve 412 (FIG. 4B), and the opened sleeve position of the inner sleeve 412 is at an uphole extent of the axial movement of the inner sleeve 412 (FIG. 4C).

The sleeve valve 400 includes the same detent mechanism as described for the sleeve valve 300, including a pair of friction rings 424a, 424b secured about the inner sleeve 412 and annular detent grooves defined in the inner surface 404 of the housing 402 (as shown in FIGS. 3E-F for the sleeve valve 300 and applicable to the sleeve valve 400). The annular detent grooves define barb surfaces configured to catch corresponding latch surfaces of the friction rings 424a, 424b, thereby engaging the friction rings 424a, 424b and the inner sleeve 412 to one another.

The sleeve valve 400 further includes a pair of sealing elements 432a, 432b secured about the inner sleeve 412 and annular seal grooves defined in the inner surface 404 of the housing 402 (as shown in FIGS. 3E-F for the sleeve valve 300 and applicable to the sleeve valve 400). In some embodiments, each sealing element 432a, 432b is an “S”-seal.

The housing 402 also defines upper and lower inner annular shoulders 440a, 440b in the bore 408, which provide upper and lower stops for the inner sleeve 412.

The sleeve valve 400 further includes top and bottom threaded connectors 442a, 442b for coupling the sleeve valve 400 to the casing. The top and bottom threaded connectors 442a, 442b form a “box-pin” configuration, with the top threaded connector 442a comprising an adapter including internal threads 444 for connecting to complementary threads of the casing, and external threads 446 for connecting to complementary internal threads 448 of the housing 402. The housing 402 defines corresponding external threads 450 for connecting to the casing at the downhole end 413.

When the top threaded connector 442a and housing 402 are threadably connected, seal elements positioned therebetween are deformed radially outward and seal against the inner surface 404 of the housing 402. In some embodiments, the seal elements comprise a pair of O-rings 452a, 452b and a central “back-up” ring 454 positioned between the O-rings 452a, 452b. Various indicia or labels 456 may be provided or attached to the housing 402.

FIGS. 5A-C are views of a third embodiment of a sleeve valve 500. The sleeve valve 500 is shown assembled in FIG. 5A. FIG. 5B is a side cross-sectional view of the sleeve valve 500 in a closed configuration. FIG. 5C is a side cross-sectional view of the sleeve valve 500 in an opened configuration. The sleeve valve 500 includes the same features as the sleeve valve 300, with the exception that the sleeve valve 500 is configured to include connectors forming a “box-box” configuration.

Without being bound by any theory, the sleeve valve (due to its short length) including the “box-box” configuration may be attached directly to a casing section by a casing manufacturer in place of a traditional casing coupler, thereby saving material, time, and expense. As a result of the shortened length, the sleeve valves may be used to couple sections of casing to replace conventional couplers or collars, and without requiring modifications to the carousel. Consequently, the overall cost may be lower than would be the case where both casing couplers and sleeve assemblies are used separately therein.

Those skilled in the art will recognize that a standard stage is typically defined as five seal points, three threads, and two engineered precision seals. The “box-to-box” configuration may eliminate one threaded connection at every stage. Considering a well with one hundred stages for example, elimination of one threaded connection at each stage may reduce the tubular stiffness, rendering the liner more pliable to run into the well; reduce the drilling rig make up time at every stage; and eliminate transport and storage logistics and costs (for example, no handling needed by personnel, reducing hazards, improving ESG).

The sleeve valve 500 comprises a tubular housing 502 having an inner surface 504 and an outer surface 506 and defining a bore 508 extending axially therethrough. The housing 502 defines one or more housing ports 510 from the inner surface 504 to the outer surface 506. The one or more housing ports 510 are arranged and aligned circumferentially about the housing 502. In this embodiment, the one or more housing ports 510 are positioned at the downhole end 513.

The sleeve valve 500 comprises an inner sleeve 512 that is axially shiftable within the housing 502 between a closed sleeve position (FIG. 5B) where the one or more ports 510 are obstructed by the inner sleeve 512, and an open sleeve position (FIG. 5C) where the inner sleeve 512 does not obstruct the one or more ports 510.

The inner surface of the inner sleeve 512 defines a tool-engaging profile 514 (FIGS. 5B-C). In this embodiment, the tool-engaging profile 514 includes annular grooves 516a, 516b, an annular rib 518, first tapered shoulders 520a, 520b, and second tapered shoulders 522a, 522b. The annular rib 518 is positioned between the second tapered shoulders 522a, 522b. In some embodiments, the annular rib 518 is narrower than the annular grooves 516a, 516b. The second tapered shoulders 522a, 522b are positioned between the annular grooves 516a, 516b.

The tool-engaging profile 514 is shaped for engaging with the locator sub 204 (FIG. 2) such that the inner sleeve 512 can be shifted between the opened or closed sleeve positions. In some embodiments, the sleeve valve 500 is configured for “shift-up-to-open” operation, meaning that the closed position of the inner sleeve 512 is at a downhole extent of the axial movement of the inner sleeve 512 (FIG. 5B), and the opened sleeve position of the inner sleeve 512 is at an uphole extent of the axial movement of the inner sleeve 512 (FIG. 5C). In some embodiments, flipping or turning around the sleeve valve 500 enables “shift-down-to-open” operation, meaning that the closed position of the inner sleeve 512 is at an uphole extent of the axial movement of the inner sleeve 512, and the opened sleeve position of the inner sleeve 512 is at a downhole extent of the axial movement of the inner sleeve 512. The sleeve valve 500 is thus versatile as it can conveniently be used for dual operations.

The sleeve valve 500 includes the same detent mechanism as described for the sleeve valve 300, including a pair of friction rings 524a, 524b secured about the inner sleeve 512 and annular detent grooves defined in the inner surface 504 of the housing 502 (as shown in FIGS. 3E-F for the sleeve valve 300 and applicable to the sleeve valve 500). The annular detent grooves define barb surfaces configured to catch corresponding latch surfaces of the friction rings 524a, 524b, thereby engaging the friction rings 524a, 524b and the inner sleeve 512 to one another.

The sleeve valve 500 further includes a pair of sealing elements 532a, 532b secured about the inner sleeve 512 and annular seal grooves defined in the inner surface 504 of the housing 502 (as shown in FIGS. 3E-F for the sleeve valve 300 and applicable to the sleeve valve 500). In some embodiments, each sealing element 532a, 532b is an “S”-seal.

The housing 502 also defines upper and lower inner annular shoulders 540a, 540b in the bore 508, which provide upper and lower stops for the inner sleeve 512.

The sleeve valve 500 further includes top and bottom threaded connectors 542a, 542b for coupling the sleeve valve 500 to the casing. The top and bottom threaded connectors 542a, 542b form a “box-box” configuration, with the top threaded connector 542a comprising an adapter including internal threads 544 for connecting to complementary threads of the casing, and external threads 546 for connecting to complementary internal threads 548a of the housing 502. The housing 502 defines internal threads 548b for connecting to the casing at the downhole end 513.

When the top threaded connector 542a and housing 502 are threadably connected, seal elements positioned therebetween are deformed radially outward and seal against the inner surface 504 of the housing 502. In some embodiments, the seal elements comprise a pair of O-rings 552a, 552b and a central “back-up” ring 554 positioned between the O-rings 552a, 552b. Various indicia or labels 556 may be provided or attached to the housing 502.

FIGS. 6A-B are views of a fourth embodiment of a sleeve valve 600. FIG. 6A is a side cross-sectional view of the sleeve valve 600 in a closed sleeve position. FIG. 6B is an enlarged side cross-sectional partial view of the sleeve valve 600. The sleeve valve 600 includes the same features as the sleeve valve 300, with the exception that the sleeve valve 600 is configured to include a different detent mechanism, as further described.

The sleeve valve 600 comprises a tubular housing 602 having an inner surface 604 and an outer surface 606 and defining a bore 608 extending axially therethrough. The housing 602 defines one or more housing ports 610 from the inner surface 604 to the outer surface 606. The one or more housing ports 610 are arranged and aligned circumferentially about the housing 602. In this embodiment, the one or more housing ports 610 are positioned at the uphole end 611.

The sleeve valve 600 comprises an inner sleeve 612 that is axially shiftable within the housing 602 between a closed sleeve position where the one or more ports 610 are obstructed by the inner sleeve 612 (FIG. 6A), and an open sleeve position where the inner sleeve 612 does not obstruct the one or more ports 610.

The inner surface of the inner sleeve 612 defines a tool-engaging profile 614. In this embodiment, the tool-engaging profile 614 includes annular grooves 616a, 616b, an annular rib 618, first tapered shoulders 620a, 620b, and second tapered shoulders 622a, 622b. The annular rib 618 is positioned between the second tapered shoulders 622a, 622b. In some embodiments, the annular rib 618 is narrower than the annular grooves 616a, 616b. The second tapered shoulders 622a, 622b are positioned between the annular grooves 616a, 616b.

The tool-engaging profile 614 is shaped for engaging with the locator sub 204 (FIG. 2) such that the inner sleeve 612 can be shifted between the opened or closed sleeve positions. The sleeve valve 600 is configured for “shift-down-to-open” operation, meaning that the closed position of the inner sleeve 612 is at an uphole extent of the axial movement of the inner sleeve 612, and the opened sleeve position of the inner sleeve 612 is at a downhole extent of the axial movement of the inner sleeve 612.

The sleeve valve 600 includes a detent mechanism that biases the inner sleeve 612 to remain in each of the open sleeve position and the closed sleeve position. The detent mechanism includes a pair of friction rings 624a, 624b, annular detent grooves 626 (only one shown for clarity in FIG. 6B) defined in the inner surface 604 of the housing 602 for receiving the friction rings 624a, 624b, retaining rings 660a, 660b, and annular retaining grooves 662 (only one shown for clarity in FIG. 6B). The inner sleeve 600 defines annular retaining grooves 662 for receiving the retaining rings 660a, 660b therein. The friction rings 624a, 624b define corresponding central annular grooves 664 (only one shown for clarity in FIG. 6B) configured to fit over the retaining rings 660a, 660b, thereby securing the friction rings 624a, 624b about the inner sleeve 612.

The sleeve valve 600 further includes a pair of sealing elements 632a, 632b secured about the inner sleeve 612 and annular seal grooves 634 (only one shown for clarity in FIG. 6B) defined in the inner surface 604 of the housing 602. In some embodiments, each sealing element 632a, 632b is an “S”-seal.

The housing 602 also defines upper and lower inner annular shoulders 640a, 640b in the bore 608, which provide upper and lower stops for the inner sleeve 612.

The sleeve valve 600 further includes top and bottom threaded connectors 642a, 642b for coupling the sleeve valve 600 to the casing. The top and bottom threaded connectors 642a, 642b form a “box-pin” configuration, with the top threaded connector 642a comprising an adapter including internal threads 644 for connecting to complementary threads of the casing, and external threads 646 for connecting to complementary internal threads 648 of the housing 602. The housing 602 defines corresponding external threads 650 for connecting to the casing at the downhole end 613.

When the top threaded connector 642a and housing 602 are threadably connected, seal elements positioned therebetween are deformed radially outward and seal against the inner surface 604 of the housing 602. In some embodiments, the seal elements comprise a pair of O-rings 652a, 652b and a central “back-up” ring 654 positioned between the O-rings 652a, 652b.

FIGS. 7A-B are views of a fifth embodiment of a sleeve valve 700. The sleeve valve 700 includes the same features as the sleeve valve 300, with the exception that the sleeve valve 700 is elongated compared to the shorter sleeve valve 300, as further described.

The sleeve valve 700 comprises an elongated tubular housing 702 having an inner surface 704 and an outer surface 706 and defining a bore 708 extending axially therethrough. The housing 702 defines one or more housing ports 710 from the inner surface 704 to the outer surface 706. The one or more housing ports 710 are arranged and aligned circumferentially about the housing 702. In this embodiment, the one or more housing ports 710 are positioned at the uphole end 711.

The sleeve valve 700 comprises an elongated inner sleeve 712 that is axially shiftable within the elongated housing 702 between a closed sleeve position where the one or more ports 710 are obstructed by the inner sleeve 712, and an open sleeve position where the inner sleeve 712 does not obstruct the one or more ports 710.

The inner surface of the inner sleeve 712 defines a tool-engaging profile (as shown in FIGS. 3E-F for the sleeve valve 300 and applicable to the sleeve valve 700) for engaging with the locator sub 204 (FIG. 2) such that the inner sleeve 712 can be shifted between the opened or closed sleeve positions. The sleeve valve 700 is configured for “shift-down-to-open” operation, meaning that the closed position of the inner sleeve 712 is at an uphole extent of the axial movement of the inner sleeve 712, and the opened sleeve position of the inner sleeve 712 is at a downhole extent of the axial movement of the inner sleeve 712.

The sleeve valve 700 includes the same detent mechanism as described for the sleeve valve 300, including a pair of friction rings 724a, 724b secured about the inner sleeve 712 and annular detent grooves defined in the inner surface 704 of the housing 702 (as shown in FIGS. 3E-F for the sleeve valve 300 and applicable to the sleeve valve 700). The annular detent grooves define barb surfaces configured to catch corresponding latch surfaces of the friction rings 724a, 724b, thereby engaging the friction rings 724a, 724b and the inner sleeve 712 to one another.

The sleeve valve 700 further includes a pair of sealing elements 732a, 732b secured about the inner sleeve 712 and annular seal grooves defined in the inner surface 704 of the housing 702 (as shown in FIGS. 3E-F for the sleeve valve 300 and applicable to the sleeve valve 700). In some embodiments, each sealing element 732a, 732b is an “S”-seal. It is to be noted that due to elongation of the sleeve valve 700, seal element 732b is positioned further along the length of the housing 702 away from the friction ring 724b (compare to the sleeve valve 300 wherein the seal element 332b is positioned adjacent the friction ring 324b).

The housing 702 also defines upper and lower inner annular shoulders in the bore 708, which provide upper and lower stops for the inner sleeve 712.

The sleeve valve 700 further includes top and bottom threaded connectors 742a, 742b for coupling the sleeve valve 700 to the casing. The top and bottom threaded connectors 742a, 742b form a “box-pin” configuration, with the top threaded connector 742a comprising an adapter including internal threads 744 for connecting to complementary threads of the casing, and external threads 746 for connecting to complementary internal threads 748 of the housing 702. The housing 702 defines corresponding external threads 750 for connecting to the casing at the downhole end 713.

When the top threaded connector 742a and housing 702 are threadably connected, seal elements positioned therebetween are deformed radially outward and seal against the inner surface 704 of the housing 702. In some embodiments, the seal elements comprise a pair of O-rings 752a, 752b and a central “back-up” ring 754 positioned between the O-rings 752a, 752b. Various indicia or labels 756 may be provided or attached to the housing 702.

The various embodiments of the sleeve valves 300, 400, 500, 600, 700 disclosed herein may be operated (i.e., open or closed) by the BHA 200 (FIG. 2) or any other suitable BHA. Using BHA 200 as an example, shifting the inner sleeve of the sleeve valve to the downhole position may be performed using hydraulic pressure or flow rate to: (1) actuate sleeve engagement elements (e.g., dogs) of a locator sub; and (2) shift the sleeve down using hydraulic forces via pressure or flow rate. Mechanical force from downhole (RIH) movement of the coiled tubing may contribute to the downward shifting. The hydraulic down-shifting may be engaged if mechanical force from coiled tubing RIH movement is insufficient for downward shifting. Shifting the inner sleeve up may be accomplished by: (1) actuating sleeve engagement elements (e.g., dogs) of the locator sub; and (2) uphole (POOH) movement of the coiled tubing, thereby pulling the locator sub upward to shift the inner sleeve.

Since the BHA 200 does not require a plug or other isolation element to grip the inner sleeve, the inner sleeve 312, 412, 512, 612, 712 may need to be engaged only by the sleeve engaging elements 502 of the locator sub 204. The locator sub 204 in this example is flow-activated. However, other means (e.g., pressure) may be used to activate a locator sub.

The locator sub 204 includes an outer body comprising one or more radially extendible and retractable sleeve engaging elements 502 (e.g., dogs) for locating and engaging an inner sleeve 312, 412, 512, 612, 712 of the sleeve valve 300, 400, 500, 600, 700. More specifically, the locator sub 204 includes a plurality of sleeve engaging elements 502 distributed circumferentially about an outer periphery of the locator sub 204. Each sleeve engaging element 502 includes projecting elements (504a, 504b, 504c) that are shaped complementary to the inner profile 314, 414, 514, 614, 714 formed by the inner surface of the inner sleeve 312, 412, 512, 612, 712 of the sleeve valve 300, 400, 500, 600, 700.

In the retracted position, the projecting elements 504a, 504b, 504c do not engage the sleeve valve 300, 400, 500, 600, 700 and may be run downhole in the casing string. In the extended position, the sleeve engaging elements 502 are extended radially to locate and engage the sleeve valve 300, 400, 500, 600, 700. When extended, the projecting elements 504a, 504b, 504c may slide along the interior of the casing string and sleeve valve 300, 400, 500, 600, 700 until they are aligned with the corresponding profile 314, 414, 514, 614, 714 of the inner sleeve 312, 412, 512, 612, 712. When aligned, the projecting elements 504a, 504b, 504c may extend fully into the corresponding profile elements 314, 414, 514, 614, 714 of the inner sleeve 312, 412, 512, 612, 712. The locator sub 204 will then be axially locked with the inner sleeve 312, 412, 512, 612, 712 until the sleeve engaging elements 502 are retracted.

The locator sub 204 is configured to be activated and extend the sleeve engaging elements 502 responsive to fluid flow through the locator sub exceeding a first flow threshold. In this embodiment, the locator sub 204 includes flow-activated element in the inner flow path that is activated by fluid flow above the first threshold to radially expand the sleeve engaging elements 502. The element may, for example, comprise an orifice, a mandrel and an internal spring(s). The orifice may be located in the flow path to convert fluid flow energy to mechanical mandrel movement to extrude the sleeve engaging elements 502. The internal spring may bias the sleeve engaging elements 502 to radially contract when fluid flow is below the first threshold. However, other mechanisms may be used to activate the sleeve engaging elements 502 responsive to fluid flow.

In the above manner, the various embodiments of the sleeve valves 300, 400, 500, 600, 700 disclosed herein may be open or closed by the BHA 200 for use in various applications including, but not limited to, downhole fracturing operations. During fracturing operations, packers (e.g., mechanical, chemical, a combination of mechanical and chemical, inflatable, swellable, etc.) are typically used to isolate sections of a wellbore, allowing the fracturing of one zone while leaving other zones untouched. To provide a seal, the packer may mechanically squeeze, expand upon exposure to a fluid pressure, and/or contain a material that swells upon exposure to a fluid or other conditions, thereby creating a barrier and preventing the fracturing fluid from flowing into unwanted zones and ensuring that stimulation is targeted at the desired zone of the formation.

Fracturing operations may also be performed without the use of packers (i.e., “packerless fracturing”). In some embodiments, the sleeve valves 300, 400, 500, 600, 700 disclosed herein may be used in packerless fracturing. Referring to FIG. 1 for example, a plurality of sleeve valves 300, 400, 500, 600, 700 may be spaced apart within the horizontal section 105. The fracturing operation may include opening one or more of the plurality of sleeve valves 300, 400, 500, 600, 700 using BHA 200 which lacks packer 212. Without packer 212, the BHA 200 may have a smaller outer diameter which contributes to a larger annulus that can better tolerate debris in the well compared to a smaller annulus taken up by the BHA 200 with packer 212. Less hardware in the well reduces the economic risk for lost and/or damaged or worn out tools and avoids the expense for hardware such as packer 212.

In an exemplary packerless fracturing operation, a first sleeve valve 300, 400, 500, 600, 700 is opened, while keeping the other sleeve valves closed and their sealing elements 332a, 332b, 432a, 432b, 532a, 532b, 632a, 632b, 732a, 732b effectively sealing and their friction rings 324a, 324b, 424a, 424b, 524a, 524b, 624a, 624b, 724a, 724b providing back-up in the event of failure of their sealing elements 332a, 332b, 432a, 432b, 532a, 532b, 632a, 632b, 732a, 732b. In a first fracturing step, fracturing fluid is pumped at pressures sufficiently high for the fracturing fluid to exit through ports 310, 410, 510, 610, 710 of the first sleeve valve 300, 400, 500, 600, 700 and fracture the formation 104 in the region of the first sleeve valve 300, 400, 500, 600, 700. The first sleeve valve 300, 400, 500, 600, 700 is closed after completion of the first fracturing step. After the fracturing has been performed, the first sleeve valve 300, 400, 500, 600, 700 is closed immediately, thereby conserving water which is the base fluid used to make up fracturing fluid.

A second sleeve valve 300, 400, 500, 600, 700 is then opened in a second wellbore zone, while keeping the first and other sleeve valves closed and their sealing elements 332a, 332b, 432a, 432b, 532a, 532b, 632a, 632b, 732a, 732b effectively sealing and their friction rings 324a, 324b, 424a, 424b, 524a, 524b, 624a, 624b, 724a, 724b providing back-up in event of failure of the sealing elements 332a, 332b, 432a, 432b, 532a, 532b, 632a, 632b, 732a, 732b. In the second fracturing step, additional fracturing fluid is pumped through the second sleeve valve to the treatment zone or the formation to form one or more fractures therethrough. The second sleeve valve is closed after completion of the second fracturing step.

A third sleeve valve 300, 400, 500, 600, 700 is then opened in a third wellbore zone, while keeping the first, second, and other sleeve valves closed and their sealing elements 332a, 332b, 432a, 432b, 532a, 532b, 632a, 632b, 732a, 732b effectively sealing and their friction rings 324a, 324b, 424a, 424b, 524a, 524b, 624a, 624b, 724a, 724b providing back-up in event of failure of the sealing elements 332a, 332b, 432a, 432b, 532a, 532b, 632a, 632b, 732a, 732b. In the third fracturing step, additional fracturing fluid is pumped through the third sleeve valve to the treatment zone or the formation to form one or more fractures therethrough. The third sleeve valve is closed after completion of the third fracturing step. The opening, fracturing, and closing steps may then be sequentially repeated for one or more of the remaining sleeve valves.

Those skilled in the art will recognize that in packerless fracturing, it is critical that the seals on all sleeve valves seal tightly and hold, particularly after they have been operated once and fracked through. In some embodiments, all sleeve valves 300, 400, 500, 600, 700 remain in the closed sleeve position at all times (see for example, FIGS. 3C, 4B, 5B, 6A), except for the sleeve valve which is in the opened sleeve position to fracture the formation 104. With reference to the above example, when the second sleeve valve is opened, the sealing elements on all other sleeve valves including the first sleeve valve need to seal tightly and hold. The wellbore (including the first sleeve valve) will pressure up when additional fracturing fluid is pumped through the second sleeve valve, with the potential for failure to occur. With the opening and closing of the first sleeve valve, it is common for the sealing elements of the first sleeve valve to have been compromised in some manner; for example, sealing elements may lose their hold when they are cut or blown out, or rock fragments become lodged within the sealing grooves during the fracturing step. In some embodiments, there may be about 50 sleeve valves in the wellbore. As more sleeve valves are opened, fractured, and closed, the risk of failure of the sealing elements increases. Once a sealing element leaks even a little, it quickly blows out and the sand erodes a bigger and bigger hole. Any sleeve valves that are not opened and closed typically never fail since they have been pressure tested during manufacture before being run downhole.

In addition to their different primary purposes as previously discussed (i.e., providing consistent drag force for the inner sleeve, scraping/wiping action to protect the sealing elements, damping effect, securing the inner sleeve in position), the friction rings act as secondary or back-up seals to the sealing elements in the event of such failure. Being formed of metal, the friction rings are more robust under harsh downhole conditions and do not wash out as easily compared to the elastomer sealing elements. The friction rings may reasonably and effectively seal about 99% or close to a complete seal.

It is to be understood that a combination of more than one of the approaches described above may be implemented. Embodiments are not limited to any particular one or more of the approaches, methods or apparatuses disclosed herein. One skilled in the art will appreciate that variations, alterations of the embodiments described herein may be made in various implementations without departing from the scope of the claims.