WO2024174023A1

WO2024174023A1 - Apparatus for selectively isolating segments of a wellbore

Info

Publication number: WO2024174023A1
Application number: PCT/CA2024/050203
Authority: WO
Inventors: Nathan Coffey; Leigh Durling; Kresten SWAIN; Dwayne WHITNEY; Andrew Buzinsky; Stuart Mclaughlin
Original assignee: Drift Wellbore Technologies Ltd
Current assignee: Drift Wellbore Technologies Ltd
Priority date: 2023-02-21
Filing date: 2024-02-20
Publication date: 2024-08-29
Anticipated expiration: 2025-08-21

Abstract

An improved wellbore isolation apparatus and methods of use during multi-stage hydraulic fracturing (MSHF) operations are provided, the apparatus operative to be both located and independently triggered by an improved wireline activation tool to easily and securely isolate specific sections the wellbore.

Description

APPARATUS FOR SELECTIVELY ISOLATING SEGMENTS OF A WELLBORE CROSS REFERENCE TO RELATED APPLICATIONS

[0001 ] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63/486,095 filed February 21 , 2023, entitled “Apparatus for Selectively Isolating Segments of a Wellbore”, which is specifically incorporated by reference herein for all that it discloses or teaches.

FIELD

[0002] Embodiments herein are generally related to improved apparatus and methods of use in multi-stage hydraulic fracturing completion operations of a subterranean wellbore, and more specifically for completion operations performed using ‘plug and perf techniques.

BACKGROUND

[0003] Well completion is the process of making a subterranean wellbore ready for production (or injection) after drilling operations. For multi-stage hydraulic fracturing (MSHF) operations, wellbore completion typically involves the running in and cementing of casing string, and then the creation of perforations through the casing string (e.g., along the horizontally-extending segment of the wellbore).

[0004] Clusters of perforations may be approximately 10-30 feet apart and the number of perforations may vary widely. A well may have more than 100 perforations. In such methods of MSHF completions, referred to as “perf and plug” methods of completion, a first cluster of perforations is formed by detonating explosive charges near the “toe” (distal end) of the casing followed by hydraulic fracturing of the formation through the perforations into a first target zone of the formation. A plug for preventing fluid flow downhole is then set above the first cluster of perforations, isolating the wellbore therebelow. A second cluster of perforations is formed above the plug and a second, subsequent fracturing treatment is performed through the second perforations (and ultimately a second target zone of the formation), and so on. That is, in MSHF operations, plug and perf process may be repeated multiple times in a single well, independently targeting different zones of the formation.

[0005] Known plug and perf operations typically lower the wellbore isolation tool (e.g., frac plug) on a wireline that is conventionally used for running the perforating gun assembly to the target location, and then using the wireline to set the plug, preventing fluid flow to the lower (isolated) portion of the wellbore. Once the plug is set, the wellbore can be perforated above the plug, providing fluid communication into the target zone for fracturing operations to commence.

[0006] Known frac plugs commonly used for plug and perf operations are manufactured from composite materials, and some metallic components requiring that the entire plug be milled out after fracturing operations are complete. Milling of frac plugs debris issues and many known operational problems for composite plugs are prone to fail during running in hole or during fracturing operations (e.g., increased fluid pressures can cause plugs to slide or slip from position within the casing string).

[0007] Frac plugs manufactured from dissolvable materials are being deployed, such plugs designed to disintegrate when contacted with brine and/or other downhole fluids. However, existing dissolvable plugs often do not fully disintegrate, resulting in a failure of the plug to set properly and/or to hold during pressure testing, and a failure to dissolve properly and/or at the desired time, leading to post-completion casing integrity anomalies. As a result, dissolvable isolation tools often still need to be milled out. Moreover, known plugs are also prone to deform during fracturing operations, reducing the bore through casing to the point that plugs cannot be deployed, and preventing fracturing from proceeding above the obstructed region. Further, where wellbores have low reservoir pressures, fluids pumped into the wellbore to remove cuttings during plug milling operations cannot be pumped from the wellbore. As a result, coiled tubing can become stuck due to the debris downhole. Although nitrified fluids can be used to remove the debris, such processes are extremely costly.

[0008] There is a need for improved wellbore isolation tools (e.g., to replace frac plugs) operative to isolate the wellbore easily and securely during MSHF plug and perf completions, the improved tools being capable of withstanding pressure testing and, when desired, of dissolving to restore the internal diameter of the casing string for subsequent wellbore operations. There is a further need for methods of controllably activating such improved wellbore isolation tools independently during MSHF processes. It is desirable that such an improved tool be run in hole with the casing string and be activated to isolate the wellbore using an improved wireline activation tool, such wireline activation tool being part of the conventional perforating gun assembly without interfering with and/or activating the perforating guns.

SUMMARY

[0009] According to embodiments, an apparatus and methods of use for selectively isolating segments of a wellbore in a subterranean formation are provided, the apparatus configured for operable connection to and run in hole with a casing string positioned within the wellbore. In some embodiments, the apparatus comprises at least one housing forming a central housing bore, at least one first valve assembly having at least one valve element actuatable between a first valve-open position, permitting fluid flow through central housing bore, and a second valve-closed position, preventing fluid flow through central housing bore, at least one actuator assembly, positioned within the central housing bore, the actuator assembly having at least one stationary tubular, at least one movable tubular, telescopically positioned within the at least one stationary tubular, and at least one actuator valve for actuating movement of the at least one movable tubular relative to the at least one stationary tubular, wherein, movement of the at least one movable tubular actuates the at least one valve element from the first valve-open position to the second valve-closed position, preventing fluid flow through the central housing bore and selectively isolating the segment of the wellbore therebelow.

[0010] In some embodiments, the apparatus may form at least one sealed annular chamber containing at least one fluid between the at least one movable tubular and the at least one stationary tubular. In some embodiments, activation of the at least one valve assembly may release the at least one fluid contained within the at least one annular chamber, causing the least one movable tubular to telescopically move relative to the at least one stationary tubular.

[0011 ] In some embodiments, the at least one valve element may comprise a flapper valve element. In some embodiments, at least a portion of the flapper valve element may be dissolvable.

[0012] In some embodiments, the actuator assembly may comprise at least two annular chambers containing at least two fluids, wherein release of fluids from a first one of the at least two annular chambers causes the at least one movable tubular to telescopically move relative to the at least one stationary tubular. In some embodiments, the actuator assembly comprises an actuator valve to trigger release of the fluids, and the actuator valve may comprise an electrical valve, a mechanical valve, a ballistic valve, an electromagnetic valve, an acoustic valve, or a combination thereof.

[0013] In some embodiments, the apparatus may further comprise at least one locator operative to transmit a signal denoting the location of the apparatus positioned within the casing string, wherein the at least one locator may comprise at least one radioactive isotope, at least one radio frequency identification tag, or a combination thereof.

[0014] According to embodiments, an improved method for selectively isolating segments of a wellbore in a subterranean formation are provided, the method comprising providing at least one apparatus in the wellbore, the at least one apparatus operably connected to the casing string to land at or near a first target location within the wellbore and having at least one valve assembly for housing at least one valve element provided in a first valve-open position, allowing fluid flow through a central bore of the casing string, and providing at least one activation tool into the casing string, the at least one activation tool configured to both detect the location of the at least one apparatus within the casing string, and to trigger the release of the at least one valve element from the at least one valve assembly of the located at least one apparatus, causing the at least one valve element to extend across and seal the central bore of the casing string in a second valve-closed position, preventing fluid flow through the central bore of the casing string.

[0015] In some embodiments, the at least one activation tool is a wireline activation tool (WAT), and the WAT can further detect at least one activation zone of at least one actuator assembly of the at least one apparatus. In some embodiments, the WAT may trigger at least one actuator valve at or near the activation zone of the at least one actuator assembly to release the at least one valve element from the at least one valve assembly.

[0016] In some embodiments, the at least one actuator valve comprises an electronic an electrical valve, a mechanical valve, a ballistic valve, an electromagnetic valve, an acoustic valve, or a combination thereof. In some embodiments, when the valve is a ballistic valve, the method comprises perforating the activation zone of the at least one actuator assembly.

[0017] In some embodiments, the at least one activation tool detects the location of the at least one apparatus by receiving a signal from at least one of radioactive isotope, a radio frequency identification tag, or a combination thereof.

[0018] In some embodiments, wherein the at least one activation tool is configured to perforate at least one activation zone of the actuator assembly to release the at least one valve element from the at least one valve assembly, wherein the at least one activation tool is further configured to perforate the at least one casing string to provide fluid communication from the central bore to the subterranean formation.

BRIEF DESCRIPTION OF THE DRAWINGS [0019] Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached Figures.

[0020] Figure 1 depicts a cross-section view of a horizontal wellbore drilled through a subterranean formation, the wellbore shown having cemented casing string positioned therein, the casing string operably engaged with at least one apparatus, according to embodiments;

[0021 ] Figure 2 depicts the wellbore of FIG. 1 , the casing string and cement having a first set of perforations created for a fracturing treatment in a first target zone of the formation, according to embodiments;

[0022] Figure 3 depicts the wellbore of FIG. 1 , the casing string and cement having three sets of perforations created for fracturing treatments of first, second, and third target zones of the formation, respectively, according to embodiments;

[0023] Figure 4 depicts a side cross-section view of an improved apparatus for use in multi-stage fracturing completion operations of a subterranean wellbore, the apparatus shown in a first valve-open position, according to embodiments;

[0024] Figure 5 depicts the apparatus of FIG. 4, the apparatus being shown in a second valve-closed position, according to embodiments;

[0025] Figure 6 depicts an exploded perspective view of the apparatus of FIGS.

4 and 5, according to embodiments;

[0026] Figure 7 depicts a zoomed in exploded perspective view of the apparatus of FIG 6, according to embodiments;

[0027] Figure 8 depicts a side cross-section view of an alternative embodiment of the improved apparatus for use in multi-stage fracturing completions of a subterranean wellbore, the alternative embodiment of the apparatus shown in a first valve-open position, according to embodiments;

[0028] Figure 9 depicts a zoomed in isolated view of a valve element of the apparatus shown in FIGS. 4, 5, and 8, according to embodiments;

[0029] Figure 10 depicts a side cross-section view of the alternative embodiment of the improved apparatus for use in multi-stage fracturing completions, the alternative embodiment of the apparatus shown in a first valve-open position, according to embodiments;

[0030] Figure 11 depicts a side cross-section view of the alternative embodiment of the improved apparatus shown in FIG. 10, the alternative embodiment of the apparatus shown having at least one wireline activation tool positioned therein, the wireline activation tool for locating and perforating a perforation zone of the apparatus positioned therein, shown in a first valve-open position, according to embodiments;

[0031 ] Figure 12 depicts a side cross-section view of the alternative embodiment of the improved apparatus shown in FIGS. 10 and 11 , the alternative embodiment of the apparatus having been activated by the at least one wireline activation tool, shown in a second valve-closed position, according to embodiments; and

[0032] Figure 13 depicts a side cross-section view of the alternative embodiment of the improved apparatus shown in FIGS. 10 and 11 , the alternative embodiment of the apparatus having at least one locator element operative to transmit at least one signal for locating the apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] According to embodiments, an improved wellbore isolation apparatus and methods of use during multi-stage hydraulic fracturing (MSHF) operations are provided. In some embodiments, the improved apparatus may be operative to easily and securely isolate specific sections of the wellbore during ‘plug and perf completions of the wellbore, while withstanding pressure testing.

[0034] In some embodiments, presently improved apparatus may be configured to be run in hole with the casing string, such that the apparatus may land at one or more predetermined locations within the wellbore (e.g., at or near target zones of interest for fracturing operations). In some embodiments, the presently improved apparatus may be configured to be controllably activated using an improved modified wireline activation tool (WAT), such activation tool configured to accurately locate the specific apparatus to be triggered and then to subsequently trigger the apparatus, without interfering with and/or activating the perforating guns. In some embodiments, the presently improved apparatus may be triggered to release at least one dissolvable valve that may be configured to dissolve at a predetermined time and/or rate, restoring the internal diameter of the casing string and fluid flow therethrough for subsequent wellbore operations.

[0035] According to embodiments, an improved wellbore isolation apparatus and methods of activating same for use during MSHF operations are provided. In some embodiments, the presently improved apparatus may be specifically configured to receive at least one signal from the at least one wireline activation tool, providing enhanced methods of activating the presently improved apparatus. In some embodiments, the presently improved apparatus may be configured for operation with and activation by one or more improved wireline activation tools for controllably actuating the presently improved apparatus.

[0036] In the present description, the terms “top/bottom”, “above/below” and “upper/lower” are used for ease of understanding and are generally intended to mean relative uphole and downhole direction from surface. The terms “longitudinal” and “transverse” are used for ease of understanding with reference to the presently improved apparatus as a whole; "length" of the apparatus or a part thereof will be with reference to the longitudinal direction of the apparatus as a whole, "depth" will be with reference to a radial direction with respect to the apparatus as a whole, and "width" will be with reference to a transverse or circumferential direction with respect to the apparatus as a whole.

[0037] The present apparatus and methods of use will now be described having regard to FIGS. 1 - 13.

[0038] According to embodiments, having regard to FIG. 1 , an example wellbore 1 is shown extending vertically (from surface) and horizontally into a subterranean formation 4 to be fractured. Wellbore 1 forms a distal heel portion 7 and extends towards a proximal toe portion 9. At least one tubular casing string 2, which may be cemented in place using conventional cementing operations, is shown installed in wellbore 1 , such casing string 2 forming a fluid passageway 3 therethrough from the surface to the toe 9. A single size casing is shown; however, it is contemplated that multiple runs of different sizes of casing string may be present within wellbore 1 . [0039] At or near the toe end 9 of wellbore 1 , casing string 2 may include a toe valve 6, the valve 6 being controlled to open allowing a point of access to the formation 4, as desired. Any suitable toe valve 6 known in the industry may be utilized, e.g., a dissolvable valve that may be triggered to open when exposed to specific fluids, a pressure activated valve triggered to open when pressure is applied from surface, or the like. For example, once cementing operations are complete and the cement has set, toe valve 6 may be triggered to open to initiate a first point of access to the formation 4, allowing for wireline activation tools, or the like, to be deployed (including the presently improved wireline activation tools, as will be described), and/or a toe frac to be performed (if required).

[0040] According to embodiments, casing string 2 may include at least one of the presently improved apparatus 100. In some embodiments, at least one apparatus 100 may be operably engaged with casing string 2, such as via threaded engagement (e.g., pin and box connection) or any other suitable connection means known in the industry, so as to be run in hole therewith. The at least one apparatus 100 may be configured to be provided in a first ‘valve open’ position, initially allowing the passage of fluids through passageway 3 of casing string 2. When desired, the at least one apparatus 100 may be controllably triggered to actuate to a second ‘valve closed’ position, preventing the passage of fluids through passageway 3 of casing string 2 and isolating a segment of casing string 2 therebelow. In some embodiments, the at least one apparatus 100 may be configured to receive at least one signal from at least one wireline activation tool, including, without limitation, an electrical, mechanical, ballistic, electromagnetic, and/or acoustic signal, or a combination thereof, as will be described. For example, having regard to FIG. 2, at least one wireline tool 8 may be lowered downhole through passageway 3 of casing string 2 so as to land at or near a desired location. In some embodiments, having regard to FIG. 3, the wireline tool 8 may be pumped downhole to land at or near a first at least one apparatus 100 (denoted as 100a), which may be positioned nearest the toe end 9 of the wellbore for a first stage of fracking to take place. Then, the subsequent operations may comprise at least the following two stages.

[0041 ] In a first stage, the wireline tool 8 may be used to selectively and controllably activate at least one valve (seal) positioned within the first apparatus 100a, causing the valve to seat across passageway 3, preventing fluid flow through therethrough and creating a pressure barrier from the top to the bottom of the wellbore 1 . In a second stage, the wireline tool 8 may then be used to trigger at least one perforation gun assembly (i.e. , perforation guns) to create a first set of perforations 5a through casing string 2 (and cement, if present) into a first zone of the formation 4. The wireline tool 8 may be removed from the casing string 10 or repositioned for the performance of a fracturing treatment. In some embodiments, the wireline tool 8 may be retrieved to surface and deployed in a neighbouring well for other conventional operations, such as ‘zipper frac’ operations, or the like.

[0042] In some embodiments, as would be known in the art, a fracturing treatment of the first zone may then be performed by introducing high-pressure frac fluids into passageway 3 and through the first set of perforations 5a, where first apparatus 100a serves to divert the fluids through first perforations 5a and to isolate the wellbore 1 and toe valve 6 therebelow. In some embodiments, it is contemplated that, one or more sensors housed within apparatus 100 may be used to record various downhole parameters, such information being transmitted uphole to surface (i.e., through the wireline tool 8).

[0043] According to embodiments, having further regard to FIG. 3, once fracturing operations of the first zone are complete, the wireline tool 8 may be repositioned and/or, if having been removed from the wellbore 1 , pumped back downhole through passageway 3 to land at or near a second desired location, such as at or near a second (uphole) apparatus 100b. For example, the wireline tool 8 may serve to selectively and controllably activate at least one valve within a second apparatus 100b, preventing fluid flow through passageway 3, and then to subsequently trigger the perforation guns to create a second set of perforations 5b for fracturing treatment of a second zone of the formation 4, and so on sequentially traveling in an uphole direction until fracturing operations of the formation 4 are complete (e.g., fracturing treatment of the formation F has occurred in at least three isolated zones via perforations 5a, 5b, and 5c, respectively).

[0044] As would be appreciated by those skilled in the art, once fracturing operations are complete, and it becomes necessary to reinstate fluid flow through passageway 3 of casing string 2, the plurality of valves positioned within each of the at least one apparatus 100a,b,c may be controllably triggered to dissolved, reinstating fluid communication from the formation 4 into casing string 2 and uphole therethrough to the surface.

[0045] According to embodiments, the presently improved apparatus 100 will now be described in more detail having regard to FIGS. 4 - 7. [0046] According to embodiments, having regard to FIG. 4, a first embodiment of the presently improved apparatus 100 may comprise a tubular housing 10 having an uphole end 11 and a downhole end 13, and forming a central bore 12 extending therebetween along longitudinal axis a. Apparatus 100 may be bookended by at least one top (uphole) connector sub and at least one bottom (downhole) connector sub. For example, at its uphole end 11 , housing 10 may comprise at least one top sub tubular 14, top sub 14 being operably engaged with housing 10 such as via threaded engagement (e.g., pin and box connection) or any other suitable connection means known in the industry.

[0047] In some embodiments, at its downhole end 13, housing 10 may comprise at least one bottom sub tubular 18, bottom sub 18 being operably engaged with housing 10 such as via threaded engagement (e.g., pin and box connection) or any other suitable connection means known in the industry. Top and bottom subs 14, 18 may serve to operatively engage with casing string 2, such as via threaded engagement (e.g., pin and box connection) or any other suitable connection means known in the industry, such that central bore 12 of housing 10 is substantially longitudinally (coaxially) aligned with the annulus of wellbore 1 . It is contemplated that any number of apparatuses 100 may be positioned within the casing string 2, each apparatus 100 being intermittently spaced along, and run in hole with, casing string 2 during conventional casing operations.

[0048] In some embodiments, housing 10 may further comprise at least one upper actuator housing 15, at least one connector sub 16, and/or at least one valve housing 17, each of the upper actuator housing 15, connector sub 16, and valve housing 17 being operably engaged within main housing 10, such as via threaded engagement or any other suitable connection known in the industry. Moreover, top sub 14, actuator housing 15, connector sub 16, and valve housing 17, and bottom sub 18, may each form central bores coaxially aligned with central bore 12 along longitudinal axis a and having a sufficient diameter so as to receive at least one actuator assembly 30 therein (as will be described). In some embodiments, about its inner surface, housing 10 may form at least one annular stop 19 (FIG. 5) for correspondingly engaging with and preventing downhole movement of the actuator assembly 30 within central bore 12 (as will be described).

[0049] In alternative embodiments, having regard to FIGS. 8 and 13, housing 10 may comprise at least one tubular bookended between at least one top sub 14 and at least one bottom sub 18, and may comprise at least one valve housing 17, the at least one top sub 14, valve housing 17, and bottom sub 18 being operably engaged within housing 10, such as via threaded engagement or any other suitable connection known in the industry. Although alternative embodiments of the presently improved apparatus 100 are provided, like elements are described using like reference numerals.

[0050] According to embodiments, apparatus 100 may further comprise at least one valve assembly 20, positioned within valve housing 17, for controlling the flow of fluids through housing central bore 12. As will be described, it is an advantage of the presently improved apparatus 100 that valve 20 may be configured to be activated or triggered by various means including, without limitation, electrical, mechanical, ballistic, electromagnetic, and/or acoustic triggering mechanisms, or a combination thereof.

[0051 ] Broadly, returning to FIGS. 4 and 5, the at least one valve assembly 20 may comprise a pivotable valve element, such as a flapper element 22, operable to actuate (e.g., about pivot point 23, FIG. 9) between a first ‘valve-open’ position, allowing fluid flow through central bore 12, and a second ‘valve-closed’ (seated) position, preventing fluid flow therethrough. Although flapper elements 22 are provided herein, such valve elements are for explanatory purposes and any means for plugging or sealing central bore 12 of casing string 2, preventing fluid flow therethrough, are contemplated.

[0052] In some embodiments, as above, the at least one valve assembly 20 may be deployed in hole within casing string 2 in a first ‘valve-open’ position (i.e., where flapper element 22 is retracted within housing 10 (e.g., valve housing 17), allowing the passage of fluids through central housing bore 12, i.e., the valve assembly 20 of apparatus 100 is open. Valve assembly 20 may remain in the valveopen position until apparatus 100 is triggered by the wireline activation tool once it has reached a predetermined target position downhole.

[0053] If and when desired, the at least one valve assembly 20 may be triggered to release flapper element 22 from housing 10 (e.g., valve housing 17), causing element 22 to sealingly extend across bore 12, plugging central bore 12 and preventing the passage of fluids therethrough, i.e., the valve 20 is closed. In this second ‘valve-closed’ position, flapper element 22 serves to isolate the section of casing string 2 therebelow. [0054] Advantageously, at least one apparatus 100 may be run in hole to land at or near at least one predetermined target location, i.e. , at or near a target fracturing zone. As above, returning to FIG. 3, a first apparatus 100a may be positioned to land such that at least one valve assembly 20 housed therewithin lands at or below a location where one or more perforations 5a will be made for fracturing a first treatment zone of the formation 4.

[0055] According to embodiments, having regard to FIG. 4, apparatus 100 may comprise an actuator assembly 30 positioned within housing 10. Having regard to FIGS. 5 and 8, actuator assembly 30 may comprise at least one first outer tubular 32 and at least one inner tubular 34. In some embodiments, one of the at least one inner or outer assembly tubulars 32,34 may be stationary, while another one of the at least one inner and outer assembly tubulars 32,34 may be telescopically movable within the stationary tubular.

[0056] In some embodiments, the at least one outer tubular 32 may be positioned within housing 10, such that tubular 32 remains stationary therein. In some embodiments, outer tubular 32 may configured to have an outer diameter sufficient to be slidably received and retained in place within the inner diameter housing 10. For example, at its uphole end, outer tubular 32 may be operably engaged with housing 10 such that tubular 34 is securely retained within central bore 12. In some embodiments, having regard to FIG. 5, at its uphole end, outer tubular 32 may be operably connected to top sub 14, such as via threaded engagement (e.g., pin and box connection) or any other suitable connection means known in the industry. In alternative embodiments, having regard to FIG. 8, at its downhole end, outer tubular 32 may be operably connected to bottom sub 18, such as via threaded engagement (e.g., pin and box connection) or any other suitable connection means known in the industry.

[0057] In some embodiments, the at least one inner tubular 34 may be movably positioned within housing 10, such that, when actuator assembly 30 is triggered, assembly tubular 34 may telescope longitudinally within housing 10 (i.e. , within outer tubular 32). In some embodiments, inner tubular 34 may be configured to have an outer diameter sufficient to be slidably received within the internal diameter of outer tubular 32. In some embodiments, the at least one inner tubular 34 may form at least one annular shoulder 39, such shoulder 39 configured for corresponding engagement with at least one annular stop 19 formed about the inner surface of housing 10. Engagement of shoulder 39 with stop 19 may serve to restrict movement of inner tubular 34 downhole (FIG. 5) or uphole (FIG. 8). Although embodiments herein describe one tubular being movable relative to a stationary tubular, it is contemplated that both tubulars may be movable relative to other another and/or relative to housing 10, without departing from the scope of the invention.

[0058] According to embodiments, having regard to FIGS. 5 and 8, actuator assembly 30 may further comprise at least one actuator valve 36 that, when triggered, serves to actuate inner tubular 34 relative to outer tubular 32, causing the release of flapper element 22 of valve 20 from the first valve-open position (i.e., where element 22 is retained valve housing 17) to the second valve-closed position (i.e., where flapper element 22 engages corresponding valve seat to seal central bore 12 and prevent fluid flow therethrough). [0059] In some embodiments, having regard to FIGS. 5 and 8, actuator assembly 30 may form at least one first sealed annular chamber 35 and at least one second sealed annular chamber 37, each chamber 35,37 being fluidically sealed, preventing exposure from fluids flowing through central bore 12 and/or the wellbore annulus.

[0060] In some embodiments, each chamber 35,37 may further be initially sealed one from the other however, when actuator valve 36 is triggered, fluids contained within first chamber 35 may be permitted to flow into second chamber 37, such release of fluids causing a decrease in pressure within chamber 35 allowing the movement of inner tubular 34 (e.g., enabling tubular 32 to telescope relative to outer tubular 32, and consequently releasing valve element 22 from valve housing 17). For example, when actuator valve 36 is triggered, at least one fluid port 33 (FIG. 7) may open, allowing fluid flow between first chamber 35 to second chamber 37.

[0061 ] According to embodiments, the at least one first annular chamber 35 may be preloaded with at least one fluid (e.g., via fluid port 38, FIG. 5), such as an inert fluid, while second annular chamber 37 may contain at least one compound, such as an inert gas (at atmospheric pressure), prior to apparatus 100 being run in hole. When apparatus 100 is positioned downhole, fluids contained within chamber 35 become pressurized relative to wellbore fluids, such increased pressures serving to retain inner tubular 34 in place relative to outer tubular 32, and operatively to retain valve element 22 in the valve-open position within valve housing 17. Inner tubular 34 may further serve to isolate valve element 22 from downhole fluids. [0062] When desired, the at least one actuator valve 36 may be triggered to open port(s) 33, allowing fluids from first chamber 35 to flow into second chamber 37, decreasing fluid pressures within chamber 35 and releasing inner tubular 34 from place relative to outer tubular 32. Movement of inner tubular 34 serves to release valve element 22 from valve housing 17, causing valve element 22 to seat across and plug fluid flow through central bore 12. Advantageously, each apparatus 100 may be independently triggered, allowing for selective segments of the wellbore to be isolated. [0063] Herein, actuator valve 36 may be described as being triggered electronically or ballistically, however, such description is for example purposes only and any suitable mechanism for enabling controlled release of fluids from chamber 35 to chamber 37 (i.e., of inner tubular 34 relative to outer tubular 32 to controllably release valve element 22 from valve housing 17) are contemplated. It is an advantage of the presently improved apparatus 100 that actuator valve 36 may be configured to be triggered by various means including, without limitation, electrical, ballistic, electromagnetic, mechanical and/or acoustic triggering mechanisms, or a combination thereof.

[0064] According to embodiments, the at least one actuator valve 36 may comprise an electronically activated valve (e.g., a solenoid valve, or the like), wherein electronic componentry (e.g., at least one solenoid switch) for activating actuator valve 36 are housed within actuator assembly 30. Electronic componentry may be sealably housed within actuator assembly 30 so as to be protected from fluids flowing through central bore 12 and/or the annulus of wellbore 1. In such embodiments, without limitation, inner tubular 34 may be operably connected to said electronic componentry such that, when activated (e.g., via a wireline activation tool, as described herein), inner tubular 34 actuates within outer tubular 32 to release valve element 22 of valve 20.

[0065] In some embodiments, having regard to FIG. 5, by way of example, the at least one annular chamber 35 may be formed between at least a portion of the inner surface of housing 10 and at least a portion of the outer surface of inner tubular 34, although any other suitable configuration is contemplated. In some embodiments, annular chamber 35 may contain at least one fluid, such fluid being preloaded into chamber 35 via fluid port 38 prior to apparatus 100 being positioned within the casing string 2. In some embodiments, the at least one annular chamber 37 may be longitudinally spaced from annular chamber 35 and may further be formed between at least another portion of the inner surface of housing 10 and at least another portion of the outer surface of inner tubular 34.

[0066] In alternative embodiments, having regard to FIG. 8, by way of example, the at least one annular chamber 35 may be formed between at least a portion of the inner surface of housing 10 and at least a portion of the outer surface of inner tubular 34, although any other suitable configuration is contemplated. At least a portion of inner tubular 34 may form at least one “activation zone” 31 , such zone forming at least one location where a portion of the sidewall of inner tubular 34 may be punctured or perforated to release fluids contained within first fluid chamber 35. That is, as above, annular chamber 35 may contain at least one fluid, such fluid being preloaded into chamber 35 prior to apparatus 100 being positioned within the casing string 2. In some embodiments, a perforation gun may be used to perforate at least one hole in tubular 34 and into hydraulic fluid chamber 35, causing the release of fluids therefrom and a corresponding decrease in hydraulic fluid pressures therein, allowing inner tubular 34 to move relative to outer tubular 32. Movement of inner tubular 34 relative to outer tubular 32 triggers the release of valve element 22 from valve housing 17 to seal central bore 12 of casing string 2.

[0067] According to embodiments, the at least one valve assembly 20 may be configured for activation by at least one wireline activation tool, whereby the wireline activation tool may be pumped downhole into casing string 2 until it lands at or near the target apparatus 100 to be triggered (e.g., proximal to a first apparatus 100a). Without limitation, when the wireline activation tool is positioned within a predetermined range of at least one apparatus 100, the tool may serve to trigger actuation valve 36 (e.g., electronically, ballistically, or the like) of actuator assembly 30, opening fluid ports 33 and forcing fluids to flow from the first annular chamber 35 (containing pressurized fluids) to the second annular chamber 37 (containing inert gas at atmospheric pressure), releasing fluid pressures within chamber 35 to actuate inner tubular 34 relative to outer tubular 32 (e.g., causing tubular 32 to travel relative to valve housing 17). Shifting of inner tubular 34 thus actuates valve assembly 20 from the first valve-open position to the second valve-closed position, enabling fracturing operations to occur thereabove.

[0068] According to embodiments, advantageously, at least a portion or all of the at least one valve element 22 may be manufactured in whole or in part from dissolvable materials. For example, it is contemplated that at least a portion of valve element 22 may be manufactured from a dissolvable material such that, when exposed to the dissolution fluids (e.g., production fluids), valve element 22 may disintegrate to reinstate fluid flow through passageway 3. In some embodiments, without limitation, valve element 22 may dissolve when exposed to wellbore production fluids, and specifically to hydrocarbons produced from formation 4 following fracturing treatment. In this manner, advantageously, each valve element 22 of each apparatus 100a, 100b, 100c, and so on, remain in the second valve-closed position throughout the duration of the wellbore completion operations, including fracturing operations, but then dissolve and allow fluid flow from formation 4 during production. It is contemplated that the presently improved apparatus 100 may further serve to provide check valves where fluid flow from the heel 7 of the wellbore 1 would aid in sealing the valves, but fluids from the toe 9 of the wellbore 1 would pass through (and potentially assist with the decomposition of) the valves.

[0069] According to embodiments, having regard to FIGS. 10 - 12, apparatus and methods for triggering the at least one valve assembly 20 of the presently improved apparatus 100 are provided. For example, it is an advantage that the presently improved apparatus 100 may be configured to receive any number of activation signals to shift valve assembly 20 to the valve-closed position, such as via a modified wireline activation tool.

[0070] For example, as above, once the casing and cementing is provided in wellbore 1 , casing 2 will generally need to be perforated prior to fracturing operations of the formation 4. Perforations may be provided using a conventional wireline activation tool to place shaped charges at the desired location within the wellbore, where the charges can be detonated to force open holes in the casing (through any cement in the annulus between the casing and into the formation 4). In this manner, communication is established between the inside of casing 2 and formation 4. Herein, embodiments described provide an improved wireline activation tool operative as both a conventional WAT (to perforate the casing string 2), but also, when desired, to independently and selectively perforate the activation/perforation zone 31 of at least one actuator assembly 30 triggering valve assembly to shift into the valve-closed position. Although embodiments described herein provide for communication with formation 4 to be established by perforating casing string 2, it is contemplated that any other means for establishing fluid communication between wellbore 1 and formation 4 (through casing string 2) is contemplated, e.g., such as via sliding sleeves within casing string 2 known in the industry, and the like. In such embodiments, it is contemplated that the WAT may trigger release of valve element 22, which may simultaneously cause one or more sleeves to shift (exposing fluid ports), opening fluid communication between wellbore 1 and formation 4.

[0071 ] According to embodiments, having regard to FIGS. 10 and 11 , the presently improved apparatus 100 provides a wireline activated valve assembly 20 that can be triggered to plug central bore 12 of casing 2, isolating a section of the wellbore 1 therebelow, such that the foregoing charges can be detonated above valve assembly 20 to create perforations 5 through the casing 2 and into the formation 4.

[0072] For example, in some embodiments, once the casing and cementing operations are completed, and at least one apparatus 100 has been positioned downhole, at least one wireline activation tool 40 may be launched into the central bore 12 of casing string 2. Wireline activation tool 40 may comprise a conventional perforation gun operative to use explosives (charges) to perforate the casing (and cement), providing communication from central bore 12 of casing 2 to formation 4. Wireline activation tool 40 may also be modified to further comprise at least one additional small perforating gun operative to use shallow explosives (charges) that only penetrate through perforation zone 31 of inner tubular 34, releasing fluids within chamber 35 and actuating inner tubular 34 to release valve element 22. It should be understood that the presently described wireline activation tool 40 provides a perforation gun(s) for both penetrating through inner tubular 34 to release valve 20 and to penetrate through casing 2 to create perforations 5 into the formation 4.

[0073] According to embodiments, having regard to FIG. 13, each of the presently improved apparatus 100 and the modified wireline activation tool may further be configured to provide a least one location mechanism such that WAT 40 may accurately locate a specific apparatus 100 to be activated. For example, having regard to FIG. 11 , wireline activation tool 40 may be lowered until positioned at or near apparatus 100a (e.g. such apparatus 100 being closest to the toe end 9 of wellbore 1 ). In some embodiments, wireline activation tool 40 may be positioned within the target “activation zone” 31 of actuator assembly 30, at or near inner tubular 34 of apparatus 100a.

[0074] Once in position, at least one small perforation gun 54 of wireline activation tool 40 may be activated to release a small, shallow charge 56, such charges 56 penetrating through inner tubular 34 (e.g., charges being controlled to penetrate a limited depth within apparatus 100, without reaching casing string 2). In some embodiments, wireline activation tool 40 may be triggered to fire the at least one shallow charges 56, ballistically activating the release of valve element 22. Although a ballistic activation of apparatus 100 is described, it should be understood that any means for triggering release of inner tubular 34 relative to outer tubular 32, releasing valve element 22, is contemplated including, without limitation, electrical, ballistic, electromagnetic, mechanical and/or acoustic triggering mechanisms, or a combination thereof.

[0075] Once valve element 22 is seated across central bore 12, isolating the wellbore 1 therebelow, wireline activation tool 40 may then be triggered to fire the at least one conventional charge(s), penetrating through casing string 2 (and cement) creating perforations 5 allowing fluid communication from central bore 12 into a first target zone of formation 4. As above, other means for establishing fluid communication with formation 4, such as shifting a sliding sleeve within casing string 2, are contemplated. Fracturing of the first target zone of formation 4 may then proceed using conventional fracturing operations.

[0076] Once fracturing of the first target zone of formation 4 is completed, wireline activation tool may wireline activation tool 40 may again be run in hole until positioned at or near a second apparatus 100b, uphole from apparatus 100a. In some embodiments, wireline activation tool 40 may be positioned within the target “penetration zone” at or near inner tubular 34 of apparatus 100b.

[0077] In some embodiments, apparatus 100 may comprise at least one locator element 50, operative to transmit at least one signal that, when received, denotes or ‘tags’ the location of the apparatus 100. For example, locator 50 may comprise at least one radioactive isotope, a radio frequency identification tag (RFID), or a combination thereof. Transmission of signal 50 may be received by at least one corresponding reader or receiver 52 positioned within wireline activation tool 40. Herein, the type, size, and position of locator element(s) 50 and receiver(s) 52 are estimates only, and any such type, size, and position of element(s) 50 and receiver(s) 52 within apparatus 100 and wireline activation tool 40, respectively or vice versa, is contemplated. Although certain locator element(s) 50 and receiver(s) 52 are described herein, such description is for explanatory purposes only, and any locator element serving to enable the wireline activation tool 40 to accurately locate at least one apparatus 100 (i.e. , at least one perforation zone 31 therein) is contemplated.

[0078] Once in position, wireline activation tool 40 may be activated to trigger the least one small perforation gun 54 to release a small, shallow charge 56, penetrating through inner tubular 34 of apparatus 100b. In this manner, wireline activation tool 40 may be used to fire at least one shallow charge 56, ballistically activating the release of valve element 22 of apparatus 100b. Although a ballistic activation of apparatus 100b is described, it should be understood that any means for triggering release of inner tubular 34 relative to outer tubular 32, releasing valve element 22, is contemplated including, without limitation, electrical, ballistic, electromagnetic, mechanical and/or acoustic triggering mechanisms, or a combination thereof.

[0079] Once valve element 22 of apparatus 100b is seated across central bore

12, isolating the wellbore 1 therebelow, wireline activation tool 40, providing conventional perforating guns 58, may again be used to fire the at least one large, conventional charge(s), penetrating through casing string 2 (and cement) creating perforations 5 allowing fluid communication from central bore 12 into each target zone of formation 4. Fracturing of each target zone of formation 4 may then proceed using conventional fracturing operations, and so on as would be understood for MSHF operations know in the industry.

[0080] The presently improved apparatus and methods of use may be used to provide individual fractures so that an amount of fluids provided into each fracture is controlled, and no operations are needed between fractures other than moving the presently described wireline activation tool 40 past the next at least one apparatus 100 and associated valve assembly 20 (and corresponding actuator assembly 30). It should be understood that any number of fracturing processes may be used, as known in the industry.

[0081 ] Although a few embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications can be made to these embodiments without changing or departing from their scope, intent or functionality. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and the described portions thereof.

Claims

WE CLAIM:

1 . An apparatus for selectively isolating segments of a wellbore in a subterranean formation, the apparatus configured for operable connection to and run inhole with a casing string positioned within the wellbore, the apparatus comprising: at least one tubular housing forming a central housing bore, at least one first valve assembly having at least one valve element actuatable between a first valve-open position, permitting fluid flow through central housing bore, and a second valve-closed position, preventing fluid flow through central housing bore, at least one actuator assembly, positioned within the central housing bore, the actuator assembly having at least one stationary tubular, at least one movable tubular, telescopically positioned within the at least one stationary tubular, and at least one actuator valve for actuating movement of the at least one movable tubular relative to the at least one stationary tubular, wherein, movement of the at least one movable tubular actuates the at least one valve element from the first valve-open position to the second valve- closed position, preventing fluid flow through the central housing bore and selectively isolating the segment of the wellbore therebelow.

2. The apparatus of claim 1 , wherein the apparatus forms at least one sealed annular chamber containing at least one fluid between the at least one movable tubular and the at least one stationary tubular.

3. The apparatus of claim 2, wherein activation of the at least one valve assembly releases the at least one fluid contained within the at least one annular chamber.

4. The apparatus of claim 3, wherein the release of the at least one fluid contained within the at least one annular chamber causes the least one movable tubular to telescopically move relative to the at least one stationary tubular.

5. The apparatus of claim 1 , wherein the at least one valve element may comprise a flapper valve element.

6. The apparatus of claim 5, wherein at least a portion of the flapper valve element may be dissolvable.

7. The apparatus of claim 1 , wherein the actuator assembly comprises at least two annular chambers containing at least two fluids, wherein release of fluids from a first one of the at least two annular chambers causes the at least one movable tubular to telescopically move relative to the at least one stationary tubular.

8. The apparatus of claim 7, wherein the actuator assembly comprises an actuator valve to trigger release of the fluids.

9. The apparatus of claim 8, wherein the actuator valve may comprise an electrical valve, a mechanical valve, a ballistic valve, an electromagnetic valve, an acoustic valve, or a combination thereof.

10. The apparatus of claim 1 , wherein the apparatus may further comprise at least one locator operative to transmit a signal denoting the location of the apparatus positioned within the casing string.

11 . The apparatus of claim 10, wherein the at least one locator may comprise at least one radioactive isotope, at least one radio frequency identification tag, or a combination thereof.

12. An improved method for selectively isolating segments of a wellbore in a subterranean formation, the method comprising: providing at least one apparatus in the wellbore, the at least one apparatus operably connected to the casing string to land at a first target location within the wellbore and having at least one valve assembly housing at least one valve element provided in a first valve-open position allowing fluid flow through a central bore of the casing string, and providing at least one activation tool into the casing string, the at least one activation tool configured to both detect the location of the at least one apparatus within the casing string, and to trigger the release of the at least one valve element from the at least one valve assembly of the located at least one apparatus, causing the at least one valve element to extend across and seal the central bore of the casing string in a second valve-closed position, preventing fluid flow through the central bore of the casing string.

13. The method of claim 12, wherein the at least one activation tool is a wireline activation tool.

14. The method of claim 13, wherein the at least one wireline activation tool can further detect at least one activation zone of at least one actuator assembly of the at least one apparatus.

15. The method of claim 14, wherein the wireline activation tool may trigger at least one actuator valve at or near the activation zone of the at least one actuator assembly to release the at least one valve element from the at least one valve assembly.

16. The method of claim 15, wherein the at least one actuator valve comprises an electronic an electrical valve, a mechanical valve, a ballistic valve, an electromagnetic valve, an acoustic valve, or a combination thereof.

17. The method of claim 16, wherein when the valve is a ballistic valve, the method comprises perforating the activation zone of the at least one actuator assembly.

18. The method of claim 12, wherein the at least one activation tool detects the location of the at least one apparatus by receiving a signal from at least one of radioactive isotope, a radio frequency identification tag, or a combination thereof.

19. The method of claim 18, wherein the at least one activation tool is configured to perforate at least one activation zone of an actuator assembly to release the at least one valve element from the at least one valve assembly.

20. The method of claim 19, wherein the at least one activation tool is further configured to perforate the at least one casing string to provide fluid communication from the central bore to the subterranean formation.