WO2017079819A1

WO2017079819A1 - Apparatuses and methods for enabling multistage hydraulic fracturing

Info

Publication number: WO2017079819A1
Application number: PCT/CA2016/000273
Authority: WO
Inventors: Brock GILLIS; Tim Johnson
Original assignee: Ncs Multistage Inc.
Priority date: 2015-11-10
Filing date: 2016-11-09
Publication date: 2017-05-18
Also published as: CA2948027A1; US20170183950A1

Abstract

There is provided a plug comprising a seat-engaging member that is deployable to a seating- ready condition such that the seat-engaging member is disposed for becoming displaced into engagement with a seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat-engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of a flow control member of the flow control apparatus for effecting opening of the port; and a seating actuator for effecting transmission of an applied force to the seat-engaging member, in response to the sensing of the trigger, for effecting the disposition of the seat-engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat.

Description

APPARATUSES AND METHODS FOR ENABLING

MULTISTAGE HYDRAULIC FRACTURING

FIELD

[0001] The present disclosure relates to flow control apparatuses which are deployable within a wellbore for controlling supply of treatment fluid to the reservoir.

BACKGROUND

[0002] Mechanical actuation of downhole valves can be relatively difficult, owing to the difficulty in deploying shifting tools on coiled tubing, or conventional ball drop systems, for actuating such valves, especially in deviated wellbores. When using conventional ball drop systems, the number of stages that are able to be treated are limited.

SUMMARY

[0003] In one aspect, there is provided a plug comprising a seat-engaging member that is deployable to a seating-ready condition such that the seat-engaging member is disposed for becoming displaced into engagement with a seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat-engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of a flow control member of the flow control apparatus for effecting opening of the port; and a seating actuator for effecting transmission of an applied force to the seat-engaging member, in response to the sensing of the trigger, for effecting the disposition of the seat-engaging member in the seating- ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat.

[0004] In another aspect, there is provided a kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a flow control apparatus including: a housing; a port disposed within the housing; a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port; a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port; and a seat; a trigger; and a plug including: a seat- engaging member that is deployable to a seating-ready condition such that the seat-engaging member is disposed for becoming displaced into engagement with the seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat- engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; and a seating actuator for effecting transmission of an applied force to the seat-engaging member, in response to the sensing of the trigger, for effecting the disposition of the seat-engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat.

[0005] In another aspect, there is provided a kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a first flow control apparatus including: a first housing; a first port disposed within the first housing; a first flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the first port; a first housing passage extending through the first housing and, while the first port is disposed in the open condition, disposed in fluid communication with the first port; and a first seat; a second flow control apparatus including: a second housing; a second port disposed within the second housing; a second flow control member displaceable relative to the second port from a closed position to an open position, for effecting opening of the second port; a second housing passage extending through the second housing and, while the second port is disposed in the open condition, disposed in fluid communication with the second port; and a second seat; a third flow control apparatus including: a third housing; a third port disposed within the third housing; a third flow control member displaceable relative to the third port from a closed position to an open position, for effecting opening of the third port; a third housing passage extending through the third housing and, while the third port is disposed in the open condition, disposed in fluid communication with the third port; and a third seat; a first trigger; and a second trigger; a first plug including: a first seat-engaging member that is deployable to a seating-ready condition such that the first seat-engaging member is disposed for becoming displaced into engagement with the first seat of the first flow control apparatus when, while the first plug is being conducted through the first housing passage, the first seat-engaging member becomes aligned with the first seat, wherein the engagement of the first seat-engaging member with the first seat is such that the first plug becomes seated on the first seat such that establishment of a first displacement-actuating pressure differential is effectible across the first plug for effecting the displacement of the first flow control member of the first flow control apparatus from the closed position to the open position; and a first seating actuator for effecting transmission of an applied force to the first seat-engaging member, in response to the sensing of the first trigger, for effecting the disposition of the first seat-engaging member in the seating- ready condition; wherein, while the first seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the first seating actuator to the first seat- engaging member, and when the first seat-engaging member becomes aligned with the first seat, the applied force effects the displacement of the first seat-engaging member into the engagement with the first seat; a second plug including: a second seat-engaging member that is deployable to a seating-ready condition such that the second seat-engaging member is disposed for becoming displaced into engagement with the second seat of the second flow control apparatus when, while the second plug is being conducted through the second housing passage, the second seat- engaging member becomes aligned with the second seat, wherein the engagement of the second seat-engaging member with the second seat is such that the second plug becomes seated on the second seat such that establishment of a second displacement-actuating pressure differential is effectible across the second plug for effecting the displacement of the second flow control member of the second flow control apparatus from the closed position to the open position; a second seating actuator for effecting transmission of an applied force to the second seat-engaging member, in response to the sensing of the second trigger, for effecting the disposition of the second seat-engaging member in the seating-ready condition; wherein, while the second seat- engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the second seating actuator to the second seat-engaging member, and when the second seat- engaging member becomes aligned with the second seat, the applied force effects the displacement of the second seat-engaging member into the engagement with the second seat; wherein each one of the first plug and the second plug, independently, is co-operatively configured with the first, second and third flow control apparatuses, and the first and second triggers such that, when the first, second and third flow control apparatuses, and the first and second triggers, are integrated into a wellbore string such that the second flow control apparatus is disposed uphole relative to the first flow control apparatus, the third flow control apparatus is disposed uphole relative to the second flow control apparatus, the first trigger is positioned uphole relative to the first seat and downhole relative to the second seat, and the second trigger is positioned uphole relative to the second seat and downhole relative to the third seat: the first plug is conductible past the third flow control apparatus and the second flow control apparatus, in sequence, while being conducted in a downhole direction through the wellbore string; and the second plug is conductible past the third flow control apparatus while being conducted in a downhole direction through the wellbore string.

[0006] In another aspect, there is provided a method of injecting treatment material into a subterranean reservoir via a wellbore string, wherein the wellbore string includes first, second and third flow control apparatuses, wherein the second flow control apparatus is disposed uphole relative to the first flow control apparatus, and the third flow control apparatus is disposed uphole relative to the second flow control apparatus, wherein each one of the flow control apparatuses, independently, includes a housing, a port disposed within the housing, a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port, a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port, and a seat configured for seating a plug such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member from the closed position to the open position, comprising: conducting a first plug in a downhole direction through the wellbore string, including: conducting the first plug through the third flow control apparatus without having effected seating of the first plug on the seat of the third flow control apparatus; after having conducted the first plug through the third flow control apparatus, conducting the first plug through the second flow control apparatus without having effected seating of the first plug on the seat of the second flow control apparatus; after having conducted the first plug through the second flow control apparatus, conducting the first plug through the first control apparatus such that the first plug becomes seated on the seat of the first flow control apparatus; after having seated the first plug on the seat of the first flow control apparatus, conducting a second plug in a downhole direction through the wellbore string, including: conducting the second plug through the third flow control apparatus without having effected seating of the second plug on the seat of the third flow control apparatus; after having conducted the second plug through the third flow control apparatus, conducting the second plug through the second control apparatus such that the second plug becomes seated on the seat of the second flow control apparatus; wherein the size of the second plug is greater than, equal to, or substantially equal to the size of the second plug.

[0007] In another aspect, there is provided a plug including: a seat-engaging member for engaging a seat of a flow control apparatus within a wellbore such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; a dissolvable closure occluding a passage; wherein the dissolvable closure is configured to dissolve in wellbore fluid such that fluid communication is effected within the wellbore between a wellbore portion that is disposed uphole relative to the plug and a wellbore portion is disposed downhole relative to the plug.

[0008] In another aspect, there is provided a kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a flow control apparatus including: a housing; a port disposed within the housing; a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port, wherein the flow control member includes grooves; a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port; and a seat; and a plug including: a seat-engaging member that is deployable to a seating- ready condition such that the seat-engaging member is disposed for becoming displaced into engagement with the seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat-engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; a seating actuator for effecting transmission of an applied force to the seat-engaging member for effecting the disposition of the seat-engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat; wherein the seat-engaging member is configured, when seated on the seat, to key into the grooves of the seat such that interference to rotation of the plug, relative to the axis of the passage, is effected, during milling out of the plug by a milling tool.

[0009] In another aspect, there is provided a kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a flow control apparatus including: a housing; a port disposed within the housing; a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port, wherein the flow control member includes grooves; a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port; and a seat; and a plug including: a seat-engaging member that is deployable to a seating- ready condition in response to sensing of the trigger such that the seat-engaging member is disposed for becoming displaced into engagement with the seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat-engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement- actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; a seating actuator for effecting transmission of an applied force to the seat-engaging member for effecting the disposition of the seat-engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat- engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat; wherein the plug includes a downhole portion, defining a downhole end, and an uphole portion defining an uphole end, wherein the downhole end includes a locking member configured to key into an uphole end of another identical, or substantially identical plug, wherein the downhole and uphole portions are co-operatively configured such that, while the seat-engaging member is seated on the seat, the seat-engaging member is retained between the downhole and uphole portions such that, after the seat-engaging member has been milled out by a milling tool, the downhole portion is pushed, by the milling tool, downhole to a plug that is disposed immediately downhole, and the locking member keys into the uphole end of such plug so as to interfere with rotation of the downhole portion during milling of the downhole portion by the milling tool.

BRIEF DESCRIPTION OF DRAWINGS

[0010] The preferred embodiments will now be described with the following accompanying drawings, in which:

[0011] Figure 1 is a schematic illustration of three flow control apparatuses disposed within a wellbore;

[0012] Figure 2A is a sectional side elevation view of an assembly, within a wellbore string, including a plug disposed within a section of a flow control apparatus that is disposed uphole of the flow control apparatus within which the plug is configured to seat, as the plug is being conducted downhole and prior to the seat-engaging member being deployed to the seating- ready condition;

[0013] Figure 2B is a sectional view of the plug illustrated in Figure 2A, with the components of the flow control apparatus omitted for clarity;

[0014] Figure 2C is an end view, taken along lines AB-AB in Figure 2B;

[0015] Figure 2D is a detailed view of Detail "AC" in Figure 2C;

[0016] Figure 3A is a sectional side elevation view of the assembly illustrated in Figure

2A, with the plug still disposed within a section of a flow control apparatus that is disposed uphole of the flow control apparatus within which the plug is configure to seat, but with the plug disposed further downhole relative to its position in Figure 2A, and with the seat-engaging member having been deployed to the seating-ready condition;

[0017] Figure 3B is a sectional view of the plug illustrated in Figure 3 A, with the components of the flow control apparatus omitted for clarity;

[0018] Figure 3C is an end view, taken along lines DD-DD in Figure 3B;

[0019] Figure 3D is a detailed view of Detail "E" in Figure 3C;

[0020] Figure 4A is a sectional side elevation view of the assembly illustrated in Figure

1A, with the plug being disposed further downhole relative to its position in Figure 3 A, and now disposed within a section of a flow control apparatus within which the plug is configure to seat, with the plug having the seat-engaging member continuing to be deployed to the seating-ready condition;

[0021] Figure 4B is a sectional view of the plug illustrated in Figure 4 A, with the components of the flow control apparatus omitted for clarity;

[0022] Figure 4C is an end view, taken along lines GG-GG in Figure 4B;

[0023] Figure 4D is a detailed view of Detail "H" in Figure 4C;

[0024] Figure 5A is a sectional side elevation view of the assembly illustrated in Figure

1A, with the plug being disposed further downhole relative to its position in Figure 4A, with the seat-engaging member having now become engaged to the seat of the flow control apparatus such that the plug is now seated on the seat of the flow control member of the flow control apparatus;

[0025] Figure 5B is a sectional view of the plug illustrated in Figure 5A, with the components of the flow control apparatus omitted for clarity;

[0026] Figure 5C is an end view, taken along lines KK- K in Figure 5B;

[0027] Figure 5D is a detailed view of Detail "L" in Figure 5C; [0028] Figure 6A is a sectional side elevation view of the assembly illustrated in Figure

1A, with the plug still seated on the seat of the flow control member of the flow control apparatus, but with the flow control member having now been shifted to the open position;

[0029] Figure 6B is a sectional view of the plug illustrated in Figure 6A, with the components of the flow control apparatus omitted for clarity;

[0030] Figure 6C is an end view, taken along lines NN-NN in Figure 6B;

[0031] Figure 6D is a detailed view of Detail "P" in Figure 6C;

[0032] Figure 7A is a sectional side elevation view of the assembly illustrated in Figure

1A, identical to the view illustrated in Figure 6A, but with the dissolvable closure now having been dissolved, and the assembly ready for flowback;

[0033] Figure 7B is a sectional view of the plug illustrated in Figure 7A, with the components of the flow control apparatus omitted for clarity;

[0034] Figure 7C is an end view, taken along lines TT-TT in Figure 7B;

[0035] Figure 7D is a detailed view of Detail "U" in Figure 7C;

[0036] Figure 8A is a sectional side elevation view of the assembly illustrated in Figure

1 A, identical to the view illustrated in Figure 7A, but with a ball having become seated to replace the function of the dissolvable closure in the case where the dissolvable closure has prematurely dissovled;

[0037] Figure 8B is a sectional view of the plug illustrated in Figure 8A, with the components of the flow control apparatus omitted for clarity;

[0038] Figure 8C is an end view, taken along lines WW- WW in Figure 8B;

[0039] Figure 8D is a detailed view of Detail "Y" in Figure 8C; [0040] Figure 9 is a sectional side elevation view of the flow control apparatus of the assembly illustrated in Figure 1A, after the flow control member has shifted, and after the plug has dissolved so as to facilitate flowback.

DETAILED DESCRIPTION

[0041] As used herein, the terms "up", "upward", "upper", or "uphole", mean, relativistically, in closer proximity to the surface and further away from the bottom of the wellbore, when measured along the longitudinal axis of the wellbore. The terms "down", "downward", "lower", or "downhole" mean, relativistically, further away from the surface and in closer proximity to the bottom of the wellbore, when measured along the longitudinal axis of the wellbore.

[0042] Referring to Figure 1, there is provided a flow control apparatus 100 for effecting selective stimulation of a subterranean formation 14, such as a reservoir 16. The flow control apparatus 100 is deployable within a wellbore 10. Suitable wellbores 10 include vertical, horizontal, deviated or multi-lateral wells.

[0043] The stimulation is effected by supplying treatment material to the subterranean formation which may include a hydrocarbon-containing reservoir.

[0044] In some embodiments, for example, the treatment material is a liquid including water. In some embodiments, for example, the liquid includes water and chemical additives. In other embodiments, for example, the treatment material is a slurry including water, proppant, and chemical additives. Exemplary chemical additives include acids, sodium chloride, polyacrylamide, ethylene glycol, borate salts, sodium and potassium carbonates, glutaraldehyde, guar gum and other water soluble gels, citric acid, and isopropanol. In some embodiments, for example, the treatment material is supplied to effect hydraulic fracturing of the reservoir.

[0045] In some embodiments, for example, the treatment material includes water, and is supplied to effect waterflooding of the reservoir. [0046] In some embodiments, for example, the treatment material includes water, and is supplied for transporting (or "flowing", or "pumping") a wellbore tool (such as, for example, a plug) downhole.

[0047] The flow control apparatus 100 may be integrated within a wellbore string 20 that is deployable within the wellbore 10. Integration may be effected, for example, by way of threading or welding.

[0048] The wellbore string 20 may include pipe, casing, or liner, and may also include various forms of tubular segments, such as flow control apparatuses described herein. The wellbore string 20 defines a wellbore string passage 22.

[0049] Successive flow control apparatuses 100, 200, 300 may be spaced from each other within the wellbore string 20 such that each flow control apparatus 100, 200, 300 is positioned adjacent a producing interval to be stimulated by fluid treatment effected by treatment material that may be supplied through a port (see below).

[0050] In some embodiments, for example, the flow control apparatus 100 includes a housing 102. A passage 104 is defined within the housing 102. The passage 104 is configured for conducting treatment material that is received from a supply source (such as at the surface) to a port 106 that extends through the housing 102.

[0051] In some embodiments, for example, the housing 102 includes interconnected upper and lower cross-over subs, and intermediate outer housing section. The intermediate housing section is disposed between the upper and lower crossover subs 102 A, 102B. In some embodiments, for example, the intermediate housing section is disposed between the upper and lower crossover subs, and is joined to both of the upper and lower crossover subs with threaded connections. Axial and torsional forces may be translated from the upper crossover sub to the lower crossover sub via the intermediate housing section.

[0052] The housing 102 is coupled (such as, for example, threaded) to other segments of the wellbore string 20, such that the wellbore string passage 22 includes the housing passage 104. In some embodiments, for example, the wellbore string 20 is lining the wellbore. The wellbore string 20 is provided for, amongst other things, supporting the subterranean formation within which the wellbore is disposed. The welbore string may include multiple segments, and segments may be connected (such as by a threaded connection).

[0053] In some embodiments, for example, it is desirable to inject treatment material into a predetermined zone (or "interval") of the subterranean formation 14 via the wellbore 10. In this respect, the treatment material is supplied into the wellbore 10, and the flow of the supplied treatment material is controlled such that a sufficient fraction of the supplied treatment material (in some embodiments, all, or substantially all, of the supplied treatment material) is directed, via the port 106, to the predetermined zone. In some embodiments, for example, the port 106 extends through the housing 102. During treatment, the port 106 effects fluid communication between the passage 104 and the subterranean formation 14. In this respect, during treatment, treatment material being conducted from the treatment material source via the passage 104 is supplied to the subterranean formation 14 via the port 106.

[0054] As a corollary, the flow of the supplied treatment material is controlled such that injection of the injected treatment material to another zone of the subterranean formation is prevented, substantially prevented, or at least interfered with. The controlling of the flow of the supplied treatment material, within the wellbore 10, is effected, at least in part, by the flow control apparatus 100.

[0055] In some embodiments, for example, conduction of the supplied treatment to other than the predetermined zone may be effected, notwithstanding the flow control apparatus 100, through an annulus, that is formed within the wellbore, between the casing and the subterranean formation. To prevent, or at least interfere, with conduction of the supplied treatment material to a zone of interval of the subterranean formation that is remote from the zone or interval of the subterranean formation to which it is intended that the treatment material is supplied, fluid communication, through the annulus, between the port 106 and the remote zone, is prevented, or substantially prevented, or at least interfered with, by a zonal isolation material. In some embodiments, for example, the zonal isolation material includes cement, and, in such cases, during installation of the assembly within the wellbore, the casing string is cemented to the subterranean formation, and the resulting system is referred to as a cemented completion. [0056] To at least mitigate ingress of cement during cementing, and also at least mitigate curing of cement in space that is in proximity to the port 106, or of any cement that has become disposed within the port, prior to cementing, the port may be filled with a viscous liquid material having a viscosity of at least 100 mm²/s at 40 degrees Celsius. Suitable viscous liquid materials include encapsulated cement retardant or grease. An exemplary grease is SKF LGHP 2TM grease. For illustrative purposes below, a cement retardant is described. However, it should be understood, other types of liquid viscous materials, as defined above, could be used in substitution for cement retardants.

[0057] In some embodiments, for example, the zonal isolation material includes a packer, and, in such cases, such completion is referred to as an open-hole completion.

[0058] In some embodiments, for example, the flow control apparatus 100 includes the flow control member 108. The flow control member 108 is displaceable, relative to the port 106, such that the flow control member 16 is positionable in open and closed positions. In this respect, the flow control member 108 is displaceable relative to the port 106 for effecting opening and closing of the port 106. The open position of the flow control member 108 corresponds to an open condition of the port 106. The closed position of the flow control member 108 corresponds to a closed condition of the port 106.

[0059] In some embodiments, for example, in the closed position, the port 106 is covered by the flow control member 108, and the displacement of the flow control member 108 to the open position effects at least a partial uncovering of the port 106 such that the port 106 becomes disposed in the open condition. In some embodiments, for example, in the closed position, the flow control member 108 is disposed relative to the port 106 such that a sealed interface is disposed between the passage 104 and the subterranean formation 30, and the disposition of the sealed interface is such that treatment material being supplied through the passage 104 is prevented, or substantially prevented, from being injected, via the port 106, into the subterranean formation 30, and displacement of the flow control member 108 to the open position effects fluid communication, via the port 106, between the passage 104 and the subterranean formation 30, such that treatment material being supplied through the passage 104 is injected into the subterranean formation 30 through the port 106. . In some embodiments, for example, the sealed interface is established by sealing engagement between the flow control member 108 and the housing 102. In some embodiments, for example, "substantially preventing fluid flow through the port 106" means, with respect to the port 106, that less than 10 volume %, if any, of fluid treatment (based on the total volume of the fluid treatment) being conducted through the passage 104 is being conducted through the port 106.

[0060] In some embodiments, for example, the flow control member 108 includes a sleeve. The sleeve is slideably disposed within the passage 104. In some embodiments, for example, the sleeve has a generally cylindrical inner wall 108 A. In some embodiments, for example, proximate its downhole end, the inner wall 108A has a taper in which the inner diameter increases in the downhole direction to define a seat 1 18 for receiving engagement of a seat-engaging member 1 19 of a plug 1 18, as is further described below.

[0061] In some embodiments, for example, the flow control member 108 is displaceable from the closed position to the open position and thereby effect opening of the port 106. Such displacement is effected while the flow control apparatus 100 is deployed downhole within a wellbore 10 (such as, for example, as part of a wellbore string 20), and such displacement, and consequential opening of the port 106, enables treatment material, that is being supplied from the surface and through the wellbore 10 via the wellbore string 20, to be injected into the subterranean formation 100 via the port 106. In some embodiments, for example, by enabling displacement of the flow control member 108 between the open and closed positions, pressure management during hydraulic fracturing is made possible.

[0062] In some embodiments, for example, the flow control member 108 is displaceable from the open position to the closed position and thereby effect closing of the port 106. Displacing the flow control member 108 from the open position to the closed position may be effected after completion of the supplying of treatment material to the subterranean formation 100 through the port 106. In some embodiments, for example, this enables the delaying of production through the port 106, facilitates controlling of wellbore pressure, and also mitigates ingress of sand from the formation 100 into the casing, while other zones of the subterranean formation 100 are now supplied with the treatment material through other ports 106. In this respect, after sufficient time has elapsed after the supplying of the treatment material to a zone of the subterranean formation 14, such that meaningful fluid communication has become established between the hydrocarbons within the zone of the subterranean formation 14 and the port 106, by virtue of the interaction between the subterranean formation 14 and the treatment material that has been previously supplied into the subterranean formation 100 through the port 106, and, optionally, after other zones of the subterranean formation 100 have similarly become disposed in fluid communication with other ports 106, the flow control member(s) may be displaced to the open position so as to enable production through the wellbore. Displacing the flow control member 108 from the open position to the closed position may also be effected while fluids are being produced from the formation 100 through the port 106, and in response to sensing of a sufficiently high rate of water production from the formation 100 through the port 106. In such case, displacing the flow control member 108 to the closed position blocks, or at least interferes with, further production through the associated port 106.

[0063] The flow control member 108 is configured for displacement, relative to the port

106, in response to application of a sufficient force. In some embodiments, for example, the application of a sufficient force is effected by a displacement-actuating pressure differential that is established across the flow control member 108. In some embodiments, for example, the sufficient force, applied to effect opening of the port 106 is a flow control member opening force, and the sufficient force, applied to effect closing of the port 106 is a flow control member closing force.

[0064] In some embodiments, for example, the housing 102 includes an inlet 1 12. While the apparatus 100 is integrated within the wellbore string 20, and while the wellbore string 20 is disposed downhole within a wellbore 10 such that the inlet 1 12 is disposed in fluid communication with the surface via the wellbore string 20, and while the port 106 is disposed in the open condition, fluid communication is effected between the inlet 1 12 and the subterranean formation 30 via the port 106, such that the subterranean formation 30 is also disposed in fluid communication, via the port 106, with the surface (such as, for example, a source of treatment fluid) via the wellbore string 20. Conversely, while the port 106 is disposed in the closed condition, at least increased interference to fluid communication, relative to that while the port 14 is disposed in the open condition (and, in some embodiments, sealing, or substantial sealing, of fluid communication), between the inlet 1 12 and the subterranean formation 30, is effected such that the sealing, or substantial sealing, of fluid communication, between the subterranean formation and the surface, via the port 106, is also effected.

[0065] In some embodiments, for example, the housing 102 includes a sealing surface configured for sealing engagement with a flow control member 108, wherein the sealing engagement defines the sealed interface described above. In some embodiments, for example, the sealing surface is defined by sealing members. In some embodiments, for example, the flow control member 108 co-operates with the sealing members to effect opening and closing of the port 106. When the port 106 is disposed in the closed condition, the flow control member 108 is sealingly engaged to both of the sealing members, and thereby preventing, or substantially preventing, treatment material, being supplied through the passage 104, from being injected into the reservoir 30 via the port 106. When the port 106 is disposed in the open condition, the flow control member 108 is spaced apart or retracted from at least one of the sealing members (such as the sealing member), thereby providing a passage for treatment material, being supplied through the passage 104, to be injected into the subterranean formation 30 via the port 106. In some embodiments, for example, each one of the sealing members, independently, includes an o- ring. In some embodiments, for example, the o-ring is housed within a recess formed within the housing 102. In some embodiments, for example, each one of the sealing members, independently, includes a molded sealing member (i.e. a sealing member that is fitted within, and/or bonded to, a groove formed within the sub that receives the sealing member).

[0066] In some embodiments, for example, the port 106 extends through the housing

102, and is disposed between the sealing surfaces.

[0067] In some embodiments, for example, the flow control apparatus 100 includes a collet (not shown) that extends from the housing 102, and is configured to releasably engage the flow closure member 108 so as to provide resistance to its displacement from selected positions relative to the housing 102 (such as the open and closed positions) such that a minimum predetermined force is required to overcome this resistance to enable displacement of the flow control member between these selected positions.

[0068] In some embodiments, for example, while the apparatus 100 is being deployed downhole, the flow control member 108 is maintained disposed in the closed position by one or more shear pins. The one or more shear pins are provided to secure the flow control member 108 to the wellbore string 20 (including while the wellbore string 20 is being installed downhole) so that the passage 104 is maintained fluidically isolated from the formation 100 until it is desired to treat the formation 100 with treatment material. To effect the initial displacement of the flow control member 108 from the closed position to the open position, sufficient force must be applied to the one or more shear pins such that the one or more shear pins become sheared, resulting in the flow control member 108 becoming displaceable relative to the port 106. In some operational implementations, the force that effects the shearing is applied by a pressure differential.

[0069] The housing 102 additionally includes a shoulder 142 to limit downhole displacement of the flow control member 108.

[0070] In some embodiments, for example, the flow control member 108 is configured for displacement, relative to the port 106, in response to application of an opening force that is effected by fluid pressure. In some embodiments, for example, the opening force is effectible while pressurized fluid is disposed uphole of a plug 1 16 such that a displacement-actuating fluid pressure differential is established across the plug 1 16. In this respect, in some embodiments, for example, the flow control member 108 is configured for displacement, relative to the port 106, in response to establishment of a displacement-actuating fluid pressure differential across the plug 1 16.

[0071] The plug 1 16 is fluid conveyable, and may take the form of a shape that cooperates with its deployment through the wellbore string 20.

[0072] In some embodiments, for example, the displacement-actuating fluid pressure differential, that is effectible across the plug 1 16, is effectible while the plug 1 16 is disposed within the passage 104 such that a sealed interface is defined within the passage 104, and the displacement-actuating fluid pressure differential, that is effectible across the plug 1 16, includes that which is effectible across the sealed interface. In this respect, the flow control member 108 is configured for displacement, relative to the port 106, in response to establishment of a displacement-actuating fluid pressure differential across the sealed interface that is defined within the passage 104 while the plug 1 16 is disposed within the passage 104. The disposition of the sealed interface is such that, when pressurized fluid is supplied to the passage 104, uphole of the sealed interface, the displacement-actuating pressure differential is established across the sealed interface such that application of the opening force is effected such that displacement of the flow control member 108 in a downhole direction (in this case, to effect opening of the port 106) is also effected. The sealed interface is with effect that sealing, or substantial sealing, of fluid communication between an uphole space 104A of the housing passage 104 and a downhole space 104B of the housing passage 104 is effected. In some embodiments, for example, the sealed interface is defined by the sealing, or substantially sealing, disposition of the plug 1 16 within the passage 104. In this respect, in some embodiments, for example, a portion of the external surface of the plug 1 16 is defined by a resilient material which functions to enable the plug to be conducted downhole through the wellbore string 20, while enabling the sealing, or substantially sealing, disposition of the plug 1 16 relative to the passage 104 to define the sealed interface.

[0073] In some embodiments, for example, the establishment of the displacement- actuating pressure differential is effectible while the plug 1 16 is seated on a seat 1 18 within the apparatus 100. In this respect, in some embodiments, for example, the flow control member 108 is configured for displacement, relative to the port 106, in response to establishment of a displacement-actuating fluid pressure differential across the plug 1 16, while the plug 1 16 is seated on the seat 1 18 that is defined within the apparatus 100.

[0074] In some embodiments, for example, the sealed interface, across which the displacement-actuating pressure differential is effectible for effecting the displacement of the flow control member 108, is effectible while the plug 1 16 is seated on the seat 1 18. In this respect, the flow control member 108 is configured for displacement, relative to the port 106, in response to establishment of a displacement-actuating fluid pressure differential across the sealed interface that is defined within the passage 104 while the plug 1 16 is seated on the seat 1 18 that is defined within the passage 104.

[0075] In some embodiments, for example, the seat 1 18 is defined as a seat profile within the apparatus 100, such as on the flow control member 108. In this respect, in those embodiments where the flow control member 108 is a sleeve, in some of these embodiments, for example, the plug 1 16 is receivable within the seat 1 18 defined within the sleeve for effecting creation of the sealed interface.

[0076] Referring to Figures 2 to 8, amongst other things, in order to avoid the use of different sized plugs for effecting fluid treatment of multiple stages within a subterranean formation through ports whose manner of opening is as above-described, the plug 1 16 includes a seat-engaging member 1 19 (such as, for example, a "dog") that is deployable to a seating-ready condition such that the seat-engaging member 1 19 is disposed for being displaced into engagement with the seat 1 18 when the seat-engaging member 1 19 becomes aligned with the seat 1 18 while the plug 1 16 is being conducted through the housing passage 104. In this respect, the plug 1 16 is co-operatively configured with the flow control apparatus 100 such that, while: (i) the plug 1 16 is being conducted through the housing passage 104, and the seat-engaging member 1 19 is disposed in the seating-ready condition, when the seat-engaging member 1 19 becomes aligned with the seat 1 18, the seat-engaging member 1 19 becomes engaged to the seat 1 18 such that the plug 1 16 becomes seated on the seat 1 18. In some embodiments, for example, the engagement of the seat-engaging member 119 to the seat 1 18 is such that the seat-engaging member 1 19 becomes coupled to the seat 1 18, such as, for example, by becoming landed on the seat 1 18. In this respect, the plug 1 16 is co-operatively configured with the apparatus 100 such that, while: (i) the plug 1 16 is being conducted through the housing passage 104, and (ii) the seat-engaging member 1 19 is disposed in the seating-ready condition, when the seat-engaging member 1 19 becomes aligned with the seat 1 18, the seat-engaging member 1 19 becomes engaged to the seat 1 18 such that the plug 1 16 becomes seated on the seat 1 18. In some embodiments, for example, the seat-engaging member 1 19 becomes engaged to the seat 1 18 by displacement of the seat-engaging member 1 19. In some embodiments, for example, the displacement includes a lateral displacement relative to the axis of the passage 104.

[0077] In the seating-ready condition, an applied force is being transmitted to the seat- engaging member 1 19. In this respect, while the seat-engaging member 1 19 is disposed in the seating-ready condition, when the seat-engaging member becomes aligned with the seat 1 18, the applied force effects the displacement of the seat-engaging member 1 19 into the engagement with the seat 1 18. [0078] When the seat-engaging member 1 19 is not deployed in the seating-ready condition, the seat-engaging member 1 19 is disposed in a non-interference condition such that, while the plug 1 16 is being conducted through the passage 104, the seat-engaging member 1 19 avoids becoming engaged to the seat 1 18 as the seat-engaging member 1 19 passes by the seat 1 18, thereby permitting the plug 1 16 to be conducted further downhole of the apparatus 100 so as to become engaged to a seat of another apparatus that is disposed further downhole, and thereby effect fluid treatment of zones within the subterranean formation 14 that are disposed further downhole. In this respect, the plug 116 is co-operatively configured with the apparatus 100 such that, while: (i) the plug 1 16 is being conducted through the housing passage 104, and (ii) the seat-engaging member 1 19 is disposed in the non-interference condition, the plug 1 16 is conductible past the seat 1 18 (such as, for example, in the downhole direction), such as, for example, to the second apparatus.

[0079] The disposition of the seat-engaging member 1 19 is configured to change from a non-interference condition to a seating-ready condition in response to sensing of a trigger condition. In some embodiments, for example, while: (i) the plug 1 16 is being conducted through the wellbore string 20, and (ii) the seat-engaging member 1 19 is disposed in the noninterference condition, in response to the sensing of a trigger condition, the seat-engaging member 1 19 becomes disposed in the seating-ready condition. In this respect, the seat-engaging member 1 19 is deployable to a seating-ready condition in response to the sensing of a trigger condition. Also, in this respect, the plug 1 16 is co-operatively configured with the flow control apparatus 100 such that, while the plug 1 16 is being conducted through the housing passage 104, the seat-engaging member 1 19 is deployable to a seating-ready condition in response to the sensing of a trigger condition such that the seat-engaging member 1 19, of the plug 1 16 being conducted through the housing passage 104, is disposed in the seating-ready condition, and while: (i) the plug 1 16 is being conducted through the housing passage 104, and (ii) the seat- engaging member is disposed in the seating-ready condition, when the seat-engaging member 1 19 becomes aligned with the seat 1 18, the seat-engaging member 1 19 engages the seat 1 18 such that the plug 1 16 becomes seated on the seat 1 18.

[0080] In some embodiments, for example, the trigger condition includes a seating- initiating profile 121 disposed within another apparatus disposed uphole relative to the apparatus 100 that includes the seat 1 18 which the seat-engaging member 1 19 is configured to engage upon deployment of the seat-engaging member 1 19 to the seating-ready condition in response to sensing of the trigger condition. In some embodiments, for example, and referring to Figures 2A to 2D and 3A to 3D, the seating-initiating profile is disposed within the passage of the another apparatus (such as apparatus 200) disposed uphole relative to the apparatus 100. In some embodiments, for example, the seating-initiating profile is defined on the flow control member of the another apparatus disposed uphole relative to the apparatus 100. In some embodiments, for example, the seating-initiating profile includes a set of grooves disposed on a passage-facing surface of the flow control member of the another apparatus disposed uphole of the apparatus 100.

[0081] In some embodiments, for example, while the seat-engaging member 1 19 is disposed in the non-interference condition, the plug 1 16 is conductible past the trigger such that there is an absence of deployment of the plug 1 16 to the seating-ready condition, such that the plug 1 16 is conductible past the seat 1 18 of the next flow control apparatus while being conducted in a downhole direction within the wellbore string. In some embodiments, for example, while the seat-engaging member 1 19 is disposed in the non-interference condition, the plug 1 16 is conductible past the trigger such that, when the seat-engaging member 1 19 becomes aligned with the seat 1 18 of the next flow control apparatus, there is a failure of engagement of the seat-engaging member 1 19 to the seat 1 18 such that the plug 1 16 fails to seat on the seat 1 18 of the next flow control apparatus while being conducted in a downhole direction within the wellbore string.

[0082] In some embodiments, for example, the change in disposition of the seat-engaging member 1 19, from the non-interference condition to the seating-ready condition, which is configured to be effected in response to the sensing of a trigger condition, is effected by a seating actuator 120 and the effecting of the change in disposition is in response to the sensing of a trigger condition and while the plug 1 16 is being conducted through the housing passage 104 by a pressurized fluid. While the seat-engaging member 1 19 is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator 120 to the seat-engaging member 1 19, and when the seat-engaging member 1 19 becomes aligned with the seat 1 18, the applied force effects the displacement of the seat-engaging member 1 19 into the engagement with the seat 1 18. In some embodiments, for example, the plug 1 16 includes the seating actuator 120.

[0083] In some embodiments, for example, the seating actuator 120 includes a force transmitter for effecting transmission of an applied force to the seat-engaging member 1 19 for effecting disposition of the seat-engaging member 1 19 in the seating-ready condition.

[0084] In some embodiments, for example, the force transmitter includes a fluid communication device 160 and a pusher 162. In some embodiments, for example, the pusher 162 includes a piston. The fluid communication device 160 is configured to effect fluid communication between the housing passage 104 and the pusher 162 while the plug 1 16 is being conducted through the housing passage 104 by a pressurized fluid such that the pressurized fluid, that is communicated from the housing passage 104, via the fluid communication device 160, to the pusher 162, applies a force to the pusher 162, that is transmitted by the pusher 162 to the seat-engaging member 1 19 such that the seat-engaging member 1 19 becomes disposed in the seating-ready condition. In some embodiments, for example, while disposed in the seating-ready condition that has being effected by the seating actuator 120, when the seat-engaging member 1 19 becomes aligned with the seat 1 18, the pusher 162 urges displacement of the seat-engaging member 1 19 into engagement with the seat 1 18 such that the plug 1 16 becomes seated on the seat 1 18. In this respect, the pusher 162 is configured to urge displacement of the seat-engaging member 1 19, when the seat-engaging member 1 19 becomes aligned with the seat while the seat- engaging member 1 19 is disposed in the seating-ready condition, such that the engagement of the seat-engaging member 1 19 to the seat 1 18 is effected and such that the seating of the plug 1 16 on the seat 1 18 is effected.

[0085] In some embodiments, for example, the fluid communication device 160 includes the fluid communication control valve 122 and the fluid communication passage 124. The fluid communication passage 124 is provided for effecting fluid communication between the housing passage 104 and the pusher 162 such that a force is transmitted by the pusher 162 to the seat- engaging member 1 19 for effecting disposition of the seat-engaging member 1 19 in the seating- ready condition, and when the seat-engaging member 1 19 becomes aligned with the seat 1 18, the transmitted force urges the seat -engaging member 1 19 to become displaced into engagement with the seat 1 18 such that the plug 1 16 becomes seated on the seat 1 18. In this respect, by virtue of the fluid communication, the pressurized fluid within the housing passage 104 communicates a force to the pusher 162, and this force is transmitted to the seat-engaging member such that disposition of the seat-engaging member 1 19 in the seating-ready condition is effected.

[0086] The establishing of the fluid communication between the housing passage 104 and the pusher 162 is controlled by the positioning of the fluid communication control valve 122 relative to the fluid communication passage 124. In this respect, the fluid communication control valve 122 is configured for displacement relative to the fluid communication passage 124. The displacement of the fluid communication control valve 122 is between a closed position to an open position. When the fluid communication control valve 122 is disposed in the closed position, sealing, or substantial sealing, of fluid pressure communication, between the passage 104 and the pusher 162, via the fluid communication passage 124, is effected. In some embodiments, for example, when disposed in the closed position, the fluid communication control valve 122 is occluding the fluid communication passage 124. When the fluid communication control valve 122 is disposed in the open position and pressurized fluid is disposed within the passage 104, fluid communication is effected, via the fluid communication passage 124, between the passage 104 and the pusher 162 such that the pressurized fluid within the housing passage 104 communicates a force to the pusher 162, and this force is transmitted to the seat-engaging member such that disposition of the seat-engaging member 1 19 in the seating- ready condition is effected.

[0087] In some embodiments, for example, the sensing of the trigger condition effects opening of the fluid communication control valve 122. In some embodiments, for example, the sensing of the trigger condition effects an application of a valve opening force by a valve actuator 164 for overcoming a biasing force that is urging disposition of the fluid communication control valve 122 to the closed position. In this respect, the valve opening force effects displacement of the fluid communication control valve 122 from the closed position to the open position. In some embodiments, for example, the biasing force, opposing the opening of the fluid communication control valve 122, is effected by a resilient member, such as a spring. In some embodiments, for example, the fluid communication control valve 122 may be suitably pressure balanced such that the fluid communication control valve 122 is disposed in the closed position.

[0088] In some embodiments, for example, the displacement of the fluid communication control valve 122 is effectible by the valve actuator 164 in response to the sensing of a trigger condition.

[0089] In some embodiments, for example, the valve actuator 164 includes a gas generator that is electro-mechanically triggered to generate pressurized gas. An example of such an actuator 164 is a squib The squib is configured to, in response to the sensing of a trigger condition, effect generation of pressurized gas. In this respect, the displacement of the fluid communication control valve 122 is effected by the force applied by the generated pressurized gas. Another suitable actuator 164 is a fuse-able link or a piston pusher.

[0090] In some embodiments, for example, the plug 1 16 further includes a sensor 128 and a controller 130. The sensor 128 is configured to sense the trigger condition. The controller 130 is configured to receive a sensor-transmitted signal from the sensor 128 upon the sensing of the trigger condition. In response to the received sensor- transmitted signal, the controller 130 supplies an actuation signal to the valve actuator 164, and the valve actuator 164 effects (or "triggers") the displacement of the fluid communication control valve 122. In some embodiments, for example, the controller 130 and the sensor 128 are powered by a battery that is also housed within the plug 1 16. In some embodiments, for example, the sensor includes a Hall effect sensor, a biased hall effect sensor, or a radio frequency identification ("RFID") sensor.

[0091] In some embodiments, for example, the seat-engaging member 1 19 is displaceable, when the seat-engaging member 119 is disposed in the seating-ready condition and becomes aligned with the seat 1 18 while the plug 1 16 is being conducted through the housing passage 104, in a lateral direction (such as, for example, radially) relative to the longitudinal axis of the housing passage 104 by the applied force being transmitted by the seating actuator 120 to the seat-engaging member 1 19. In this respect, the engagement of the seat-engaging member 1 19 with the seat 1 18 is effected by lateral displacement of the seat-engaging member 1 19. [0092] In some embodiments, for example, the seat-engaging member 1 19 is positionable relative to an external surface 1 16A of the plug 1 16 such that, when the seat-engaging member 1 19 becomes laterally displaced such that the seat-engaging member 1 18 is engaged to the seat 1 18, the seat-engaging member 1 19 is partially recessed into the external surface 1 16A of the plug 1 16 such that opposition to conduction of the plug 1 16 through the housing passage 104 in a downhole direction is effected and such that the seating of the plug 1 16 on the seat 1 18 is thereby effected. In this respect, in some embodiments, for example, the partial recessing of the seat- engaging member 1 19 is through a window 166 defined within a plug housing 168 of the plug 1 16, with the window 166 defining a shoulder 190. Also, in this respect, the seat-engaging member 1 19 is mounted within the window 166 such that the seat-engaging member 1 19 is axially fixed, or substantially axially fixed, relative to the plug housing 168.

[0093] In some embodiments, for example, the plug housing 168 includes an uphole portion 170 and a downhole portion 172. The uphole portion 172 is partially received by one end of the downhole portion 170. In the illustrated embodiment, the window 166 is defined through the downhole portion 170, and the seating actuator 120 includes the fluid communication device 160 and a pusher 162. The pusher 162 is mounted within and displaceable relative to the plug housing 168. The pusher 162 includes an uphole end 162A which fits around a downhole end 170A of the uphole portion 170 of the plug housing 168. In the illustrated embodiment, the pusher 162 is in the form of a sleeve. When the pusher 162 is disposed in an un-actuated condition, the uphole end 162A of the pusher is abutting (or at least in close proximity to) a radially outwardly-projecting shoulder 174 of the uphole portion 170 of the plug housing 168. The pusher 162 includes a radially outwardly-projecting flange 176 that engages the inner wall 178 of the uphole portion 170 of the plug housing 168. The shoulder 174, the flange 176, and the inner wall 178 of the uphole portion 170 co-operate to define a chamber 180 to which fluid communication is effectible with the housing passage 104 via the fluid communication passage 124, such that, when pressurized fluid is disposed within the passage 104, fluid communication is effected, via the fluid communication passage 124, between the passage 104 and the chamber 180 such that the pressurized fluid within the housing passage 104 communicates a force to the pusher 162, and this force is transmitted to the seat-engaging member such that disposition of the seat-engaging member 1 19 in the seating-ready condition is effected. [0094] In some embodiments, for example, the pusher 162 and the plug housing 168 are co-operatively configured such that a low pressure chamber 181 , that contains a low pressure fluid (such as a gas disposed at atmospheric pressure), is disposed between the pusher 162 and the plug housing 168, with effect that the area of the surface portion of the pusher 162 that is exposed to pressurized fluid within the wellbore, while fluid communication is being effected between the passage 104 and the chamber 180, is such that a sufficient force imbalance is effected across the pusher 162 (for example, in the downhole direction) such that sufficient force is transmitted to the seat-engaging member 1 19 for effecting the lateral displacement of the seat- engaging member 1 19 at a sufficiently fast rate to effect the engagement of the seat-engaging member 1 19 to the seat 1 18 when the seat-engaging member 1 19 becomes aligned with the seat 1 18.

[0095] Referring to Figure 3 A to 3D, in some embodiments, for example, the pusher 162 includes a plurality of teeth 182. The teeth 182 are formed on the outer surface of the pusher 162 proximate its downhole end. The teeth 182 have inclined cam surfaces 182A which taper inwardly in the downhole direction.

[0096] Also referring to Figure 3 A to 3D, the seat-engaging surface 1 19 includes a plurality of teeth 184 having inclined follower surfaces 184A corresponding to the cam surfaces 182A and matingly engaging the teeth 182 of the pusher 162. While the seat-engaging member 1 19 is non-aligned (i.e. out of alignment) relative to the seat 1 18, the flow control member retains the seat-engaging member 1 19 in a position such that the seat-engaging member 1 19 is disposed within the window 166 and the teeth 182, 184 interlock.

[0097] When the trigger is sensed by the sensor such that fluid communication is effected between the housing passage 104 and the chamber 180, fluid invades and pressurizes the chamber 180. This communicates a force to the pusher 162, and this force is transmitted to the seat-engaging member such that disposition of the seat-engaging member 1 19 in the seating- ready condition is effected. This force urges the pusher 162 in the downhole direction, and the teeth 182 of the pusher bear against the teeth 184 of the seat-engaging member 1 19, urging the seat-engaging member 1 19 radially outwardly, and such displacement is resisted by the flow control member 108 (as described above), so long as there is an absence of alignment between the seat-engaging member 1 19 and the seat 1 18. In parallel, and by virtue of the interlocking of the teeth 182, 184 displacement of the pusher 162 relative to the housing is resisted. This condition of the plug is illustrated in Figures 3A to 3D and 4A to 4D, and the seat-engaging member 119 is disposed in the seating-ready condition.

[0098] Referring to Figures 5 A to 5D, while the pusher 162 is transmitting the applied force to the seat-engaging member 1 19 (such that the seat-engaging member 1 19 is disposed in the seating-ready condition), and when the seat-engaging member 1 19 becomes aligned with the seat 1 18, the opposition to lateral (for example, radial) displacement of the seat-engaging member 1 19 is removed. Accordingly, the cam surfaces 182 A progressively advance against the follower surfaces 184A, and the shoulder 190 co-operates with the seat-engaging member 1 19 while the cam surfaces 182A progressively advance against the follower surfaces 184A such that the lateral displacement of the seat-engaging member 1 19 into the engagement with the seat 1 18 is effected and such that the seating of the plug 1 16 on the seat 1 18 is effected. In parallel, the pusher 162 is displaced downhole relative to the plug housing 168, eventually bottoming out against a stop 192. As mentioned above, because the seat-engaging member 1 19 is mounted within the window 166 such that the seat-engaging member 1 19 is axially fixed, or substantially axially fixed, relative to the plug housing 168, when the seat-engaging member 1 19 is disposed in engagement to the seat 1 18, the seat 1 18 functions to interfere with conduction of the plug 1 16 in the downhole direction such that the plug 1 16 is seated on the seat 1 18.

[0099] Referring again to Figures 1A to ID, in some embodiments, for example, a second flow control apparatus 200 and a third flow control apparatus 300 are provided for incorporation within the wellbore string 20 along with the flow control apparatus 100. Each one of the first, second and third flow control apparatuses, independently, includes a respective trigger condition. In some embodiments, for example, each one of the trigger conditions, independently, includes a seating-initiating profile defined within the apparatus. Parts of the second and third flow control apparatuses 200, 300 that are alike with parts of the first flow control apparatus 100 are labelled using the same reference numeral incremented by "Ί 00". With the exception of the trigger condition, the first, second and third flow control apparatuses 200, 300 are identical, or substantially identical, to each other. Plugs 1 16 and 216 are also provided. The plug 1 16 is configured for seating within the apparatus 100, as described above. The plug 216 is configured for seating within the apparatus 200, as described above. The trigger condition that, when sensed by the plug 1 16, while the plug 1 16 is being conducted downhole within the wellbore string 20, effects a change in condition of the plug 1 16 from the noninterference condition to the seating-ready condition, is a "first trigger condition", and the first trigger condition is disposed within the second flow control apparatus 200, downhole from the second seat 218, such that the second flow control apparatus 200 includes the first trigger condition. The trigger condition that, when sensed by the plug 216, while the plug is being conducted downhole within the wellbore string 20, effects a change in condition of the plug 216 from the non-interference condition to the seating-ready condition, is a "second trigger condition", and the second trigger condition is disposed within the third flow control apparatus 200, downhole from the third seat 318, such that the third flow control apparatus 200 includes the second trigger condition.

[00100] In some embodiments, for example, a plug 316 is also provided and is configured for seating within the apparatus 300. The seating of the plug 316 is effected in response to sensing of a trigger condition (the "third trigger condition"), and in some of these embodiments, for example, the third trigger condition is disposed in another flow control apparatus that is disposed uphole relative to the third flow control apparatus 300. The third flow control apparatus 300 is, with the exception of the trigger condition, identical, or substantially identical, to each one of the flow control apparatuses 100, 200, 300, independently.

[00101] In some embodiments, for example, the first, second and third flow control apparatuses 100, 200, 300 are co-operatively configured such that, while integrated within a wellbore string 20 such that the second flow control apparatus 200 is disposed uphole relative to the first flow control apparatus 100, and the third flow control apparatus 300 is disposed uphole relative to the second flow control apparatus 200, and while the plug 1 16 is being conducted through the wellbore string 20: the plug 1 16 is conducted through the third flow control apparatus 300 without having become seated on the seat 318 of the third flow control apparatus 300; and after having been conducted through the third flow control apparatus 300, the plug 216 is conducted through the second flow control apparatus 200 without having becoming seated on the seat 218 of the second flow control apparatus 200; and after having been conducted through the second flow control apparatus 200, and while the plug is being conducted through the first flow control apparatus 100, the plug 1 16 becomes seated on the seat 1 18 of the first flow control apparatus 100. and after the plug 1 16 has been conducted through the second flow apparatus (such as, for example, after the plug 1 16 has become seated on the seat 1 18), and while the plug 216 is being conducted through the wellbore string 20: the plug 216 is conducted through the third flow control apparatus 300 without having become seated on the seat 318 of the third flow control apparatus 300; and after having been conducted through the second flow control apparatus 300, and while the plug 216 is being conducted through the second flow control apparatus 200, the plug 216 becomes seated on the seat 218 of the second flow control apparatus 200.

[00102] In some embodiments, for example, the size of the second plug is greater than, equal to, or substantially equal to the size of the second plug. In some embodiments, for example, the first plug has the same, or substantially the same, dimensions as the second plug.

[00103] In some embodiments, for example, the first, second and third flow control apparatuses 100, 200, 300 are co-operatively configured such that, while integrated within a wellbore string 20 such that the second flow control apparatus 200 is disposed uphole relative to the first flow control apparatus 100, and the third flow control apparatus 300 is disposed uphole relative to the second flow control apparatus 200, and while the plug 1 16 is being conducted through the wellbore string 20: the plug 1 16 is conducted through the third flow control apparatus 300 without having effected deployment of the seat-engaging member 1 19 to the seating-ready condition, such that the plug 1 16 is conducted through the third flow control apparatus without having become seated on the seat 318 of the third flow control apparatus 300; and after having been conducted through the third flow control apparatus 300, the plug is conducted through the second flow control apparatus 200 without having effected deployment of the seat-engaging member 1 19 to the seating-ready condition until at least after the seat-engaging member 1 19 has passed the seat 218, such that the plug 1 16 is conducted through the second flow control apparatus 200 without having become seated on the seat 218 of the second flow control apparatus 200; and after the seat-engaging member 1 19 has passed the seat 218, and before having passed the seat 1 18 of the first flow control apparatus 100, in response to sensing of the first trigger condition disposed within the second flow control apparatus 200, the seat-engaging member 1 19 becomes deployed in the seating-ready condition; and after having been conducted through the second flow control apparatus 200, and while being conducted through the first flow control apparatus 100 with the seat-engaging member 1 19 deployed in the seating-ready condition, the plug 1 16 becomes seated on the seat 1 18 of the first flow control apparatus 100; and after the plug 1 16 has been conducted through the second flow apparatus (such as, for example, after the plug 1 16 has become seated on the seat 1 18), and while the plug 216 is being conducted through the wellbore string 20: the plug 216 is conducted through the third flow control apparatus 300 without having effected deployment of the seat-engaging member 219 to the seating-ready condition until at least after the seat-engaging member 219 has passed the seat 318, such that the plug 216 is conducted through the third flow control apparatus without having become seated on the seat 318 of the third flow control apparatus 300; and after the seat-engaging member 219 has passed the seat 318, and before having passed the seat 218 of the second flow control apparatus 200, in response to sensing of the second trigger condition disposed within the third flow control apparatus 300, the seat-engaging member 219 becomes deployed in the seating-ready condition; and after having been conducted through the second flow control apparatus 300, and while being conducted through the second flow control apparatus 200 with the seat-engaging member 219 deployed in the seating-ready condition, the plug 216 becomes seated on the seat 218 of the second flow control apparatus 200.

[00104] In some embodiments, for example, the plug 1 16 is configured to ignore the second trigger condition of the third apparatus 300.

[00105] In some embodiments, for example, the ignoring of the second trigger condition by the plug 116 is such that the plug 1 16 is conductible past the second trigger condition such that there is an absence of deployment of the plug 1 16 to the seating-ready condition, such that the plug 1 16 is conductible past the second flow control apparatus 200 while being conducted in a downhole direction within the wellbore string.

[00106] In some embodiments, for example, the ignoring of the second trigger condition by the plug 1 16 is such that the plug 116 is conductible past the second trigger condition such that, when the seat-engaging member 1 19 becomes aligned with the seat 218, there is a failure of engagement of the first-engaging member 119 to the seat 218 such that the plug 1 16 fails to seat on the seat 218 while being conducted in a downhole direction within the wellbore string.

[00107] In some embodiments, for example, the ignoring of the second trigger condition by the plug 1 16 is such that the plug 1 16 is conductible past the second trigger condition such that there is an absence of deployment of the plug 1 16 to the seating-ready condition such that, when the seat-engaging member 1 19 becomes aligned with the seat 1 18, there is a failure of engagement of the seat-engaging member 1 19 to the seat 1 18 such that the plug 1 16 fails to seat on the seat 1 18, such the plug 116 is conductible past the second flow control apparatus 200 while being conducted in a downhole direction within the wellbore string.

[00108] It is understood that additional flow control apparatuses may be incorporated within the wellbore string 20, and that such additional flow control apparatuses may be identical, or substantially identical, to the first, second and third flow control apparatuses 100, 200, 300, with the exception that the trigger condition of each one of the flow control apparatuses, independently, is different.

[00109] In another aspect, a kit may also be provided, and include the first, second and third flow control apparatuses 100, 200, 300, and also include the plug 1 16. In some embodiments, for example, the kit also includes the plug 216, and, in some embodiments, for example, the plug 316. It is understood that additional flow control apparatuses may be incorporated within the kit, as well as corresponding plugs, and that such additional flow control apparatuses may be identical, or substantially identical, to the first or second flow control apparatuses 100, 200, with the exception that the trigger condition of each one of the flow control apparatuses is different.

[00110] An exemplary process for supplying treatment fluid to a subterranean formation, through a wellbore string 20, disposed within a wellbore, and incorporating any one of the above-described embodiments of the flow control apparatus, will now be described.

[00111] The plug 1 16 is conducted downhole (such as being pumped with flowing fluid) through the wellbore string 20 (disposed within the wellbore 10) including the first, second and third flow control apparatuses 100, 200, 300 (as described above). The second flow control apparatus 200 is disposed uphole relative to the first flow control apparatus 100. The third flow control apparatus 300 is disposed uphole relative to the second flow control apparatus 200. When introduced into the wellbore string, the plug 1 16 is disposed in the non-interference condition.

[00112] The plug 116 is conducted through the third flow control apparatus 300 without having effected deployment of the seat-engaging member 1 19 to the seating-ready condition, such that the plug 1 16 is conducted through the third flow control apparatus without having become seated on the seat 316 of the third flow control apparatus 300. After having been conducted through the third flow control apparatus 300, the plug 1 16 is conducted through the second flow control apparatus 200 without having effected deployment of the seat-engaging member 1 19 to the seating-ready condition until at least after the seat-engaging member 1 19 has passed the seat 218, such that the plug 1 16 is conducted through the second flow control apparatus 200 without having become seated on the seat 216 of the second flow control apparatus 200. Referring to Figures 2 A to 2D, while being conducted through the second flow control apparatus 200, the plug 1 16 senses the first trigger condition (embodied in the trigger 221) within the second flow control apparatus 200, such as with the on-board sensor 128. In response, the seat-engaging member 1 19 is deployed (in accordance with any one of the embodiments described above), such that the seat-engaging member 1 19 becomes disposed in the seating-ready condition before the seat-engaging member 1 19 passes the seat 1 18 within the first flow control apparatus 100 (see Figures 3 A to 3D). After having been conducted through the second flow control apparatus 200, the plug 1 16 is received within the first flow control apparatus 100 with the seat-engaging member 1 19 deployed in the seating-ready condition (see Figures 4A to 4D). Referring to Figures 5A to 5D, while being conducted through the first flow control apparatus 100 with the seat-engaging member 1 19 deployed in the seating-ready condition, the plug 1 16, via the seat-engaging member 1 19, becomes seated on the seat 1 18 of the first flow control apparatus 100. Once the plug 1 16 is seated on the seat 1 18, pressurized fluid is supplied uphole of the seated first plug 1 16 such that the flow control member 108 of the first apparatus 100 becomes displaced to the open position (see Figures 6A to 6D). Treatment fluid is then supplied to the subterranean formation through the first port 106 to effect treatment of the zone of the subterranean formation in the vicinity of the port 106. After the treatment is completed, the supplying of the treatment fluid is suspended.

[00113] After the supplying of the treatment fluid has been suspended, the plug 216 is introduced into the wellbore string 20 and is conducted downhole through the wellbore string 20. When introduced into the wellbore string 20, the plug 216 is disposed in the non-interference condition. The plug 216 is conducted through the third flow control apparatus 300 without having effected deployment of the seat-engaging member 219 to the seating-ready condition until at least after the seat-engaging member 219 has passed the seat 318, such that the plug 216 is conducted through the third flow control apparatus 300 without having become seated on the seat 316 of the third flow control apparatus 300. While being conducted through the second flow control apparatus 200, the plug 216 senses the second trigger condition, such as with the onboard sensor 128. In response, the seat-engaging member 219 is deployed (in accordance with any one of the embodiments described above), such that the seat-engaging member 219 becomes disposed in the seating-ready condition before the seat-engaging member 219 passes the seat 218 within the second flow control apparatus 200. After having been conducted through the second flow control apparatus 300, and while being conducted through the second flow control apparatus 200 with the seat-engaging member 219 deployed in the seating-ready condition, the plug 216, via the seat-engaging member 219, becomes seated on the seat 218 of the second flow control apparatus 200. Once the plug 216 is seated on the seat 218, pressurized fluid is supplied uphole of the seated second plug 216 such that the flow control member 208 of the second apparatus 200 becomes displaced to the open position. Treatment fluid is then supplied to the subterranean formation through the port 206 to effect treatment of the zone of the subterranean formation in the vicinity of the port 206. After the treatment is completed, the supplying of the treatment fluid is suspended.

[00114] This process may be repeated with additional combinations of flow control apparatuses and plugs, and, in some embodiments, with additional combinations of flow control apparatuses and plugs that are co-operatively configured such that the plug ignores trigger conditions of all flow control apparatuses that are disposed uphole relative to the flow control apparatus within which the plug is intended to be seated so as to effect the opening of the port (the "corresponding flow control apparatus), with the exception of the flow control apparatus that is disposed immediately uphole of the corresponding flow control apparatus. In this way, the same size plug could be used to effect treatment of multiple zones, such that the number of zones being treated within the subterranean formation is not limited in the same manner as it is with conventional ball drop systems..

[00115] After the subterranean formation has been sufficiently treated with treatment fluid, in accordance with the process as above-described, it is desirable to effect flow back and, therefore, production of the hydrocarbon material from the reservoir of the subterranean formation. In some embodiments, for example, in order to effect flowback, the plugs 1 16, 216 may be milled out, thereby creating fluid communication between the open ports 1 18, 218 and the wellhead.

[00116] In other embodiments, for example, the plug 1 16 may be suitably designed to enable flowback. In this respect, in some embodiments, for example, the plug 1 16 includes a passage 132 that is occluded by a dissolvable closure 134 such that, while the plug 1 16 is seated on the seat 1 18, fluid flow is prevented, or substantially prevented, through the passage 132, between a portion of the wellbore string 20 that is disposed downhole relative to the plug 1 16 and a portion of the wellbore string 20 that is disposed uphole relative to the plug 1 16. The dissolvable closure 134 is configured to dissolve within wellbore fluids, such that fluid communication between the downhole and uphole wellbore portions have been established, after a time interval that is sufficient to enable treatment of all the desired zones with the wellbore string 20 (see Figures 7A to 7D). After the closure 134 has dissolved, flowback may be implemented. In some embodiments, for example, the material of construction of the dissolvable closure 134 includes.

[00117] In some embodiments, for example, the plug 116 is further configured to mitigate the risk of premature dissolving of the dissolvable closure 134. If the dissolvable closure 134 dissolves prior to the opening of the port 106, then the displacement-actuating fluid pressure differential cannot be established across the plug 1 16 unless another way of occluding the passage 132 is provided. In this respect, and referring to Figures 8A to 8D, in some embodiments, for example, the plug 1 16 includes a seat 194 within the passage 132 for landing of a ball 196 on the seat 194, such that the ball 196 is seated on the seat 194 and thereby occludes the passage 132, and thereby enables the establishment of the displacement-actuating fluid pressure differential.

[00118] In some embodiments, for example, the plug 1 16, itself, is dissolvable, for purposes of flowback. Figure 9 illustrates a condition of the flow control apparatus 100 after the plug 1 16 having been dissolved.

[00119] In some embodiments, for example, the flow control apparatus 100 is cooperatively designed with the plug 1 16 to provide "anti-rotation" features for mitigating rotation of the plug 1 16 relative to the flow control apparatus 100 during milling operations, such as those performed to effect flowback. It is understood that these features may be provided with the flow control apparatus / plug combinations 200/216 and 300/316, as well as all other flow control apparatus / plug combinations that are used within the wellbore system.

[00120] In some embodiments, for example, with respect to the seat-engaging member

1 19, the flow control apparatus 100 (such as, for example, and more specifically, the flow control member 108) includes grooves, and the seat-engaging member 1 19 is configured, when seated on the seat 1 18, to key into grooves such that interference to rotation of the plug 1 16, relative to the axis of the passage 104, is effected, such that the plug 1 16 is disposed for being milled out by a milling tool. In some embodiments, for example, the interference is such that the rotation is prevented or substantially prevented. [00121] As above-described, in some embodiments, for example, and referring to Figures 6A to 6D, the plug 1 16 includes the plug housing 168, and the plug housing 168 includes a downhole housing portion 170 and an uphole housing portion 172. The downhole housing portion 170 defines a downhole end 170A, and the uphole housing portion 172 defines an uphole end 172A. The downhole end 170A defines seat-engaging members 170B configured to key into a downhole end of another identical, or substantially identical plug. The downhole and uphole housing portions 170, 172 are co-operatively configured such that, while the seat-engaging member 1 19 is seated on the seat 1 18, the seat-engaging member 1 19 is retained between the downhole and uphole housing portions 170, 172. In this respect, during milling operations, after the seat-engaging member 1 19 has been milled out, the downhole portion is pushed down to a plug that is disposed immediately downhole, and the downhole portion keys into the uphole end of such plug so as to enable milling of the downhole portion 136.

[00122] In the above description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the present disclosure. Although certain dimensions and materials are described for implementing the disclosed example embodiments, other suitable dimensions and/or materials may be used within the scope of this disclosure. All such modifications and variations, including all suitable current and future changes in technology, are believed to be within the sphere and scope of the present disclosure. All references mentioned are hereby incorporated by reference in their entirety.

Claims

CLAIMS What is claimed is:

1. A plug comprising a seat-engaging member that is deployable to a seating-ready condition such that the seat- engaging member is disposed for becoming displaced into engagement with a seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat- engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of a flow control member of the flow control apparatus for effecting opening of the port; and a seating actuator for effecting transmission of an applied force to the seat-engaging member, in response to the sensing of the trigger, for effecting the disposition of the seat-engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat.

2. The plug as claimed in claim 1, further comprising: a sensor for sensing the trigger.

3. The plug as claimed in claim 1 or 2: wherein the seat-engaging member is deployable from a non-interference condition, wherein, in the non-interference condition, the seat-engaging member is disposed such that, while the plug is being conducted through the housing passage of the flow control apparatus, there is a failure to effect engagement of the seat-engaging member to the seat when the seat-engaging member becomes aligned with the seat.

4. The plug as claimed in claim 1 to 3; wherein: the seating actuator includes a fluid communication device and a pusher; the fluid communication device is configured to effect fluid communication between the housing passage of the flow control apparatus and the pusher, while the plug is being conducted through the housing passage by a pressurized fluid, such that the pressurized fluid, that is communicated from the housing passage, via the fluid communication device, to the pusher, applies a force to the pusher, that is transmitted by the pusher to the seat-engaging member, such that the deployment of the seat-engaging member to the seating-ready condition is effected, and such that, in the seating-ready condition, pressurized fluid is being communicated from the housing passage, via the fluid communication device, to the pusher, and applying a force to the pusher, and the applied force is being transmitted by the pusher to the seat-engaging member; and the pusher is configured to urge displacement of the seat-engaging member, when the seat-engaging member becomes aligned with the seat while the seat-engaging member is disposed in the seating-ready condition, such that the engagement of the seat-engaging member to the seat is effected and such that the seating of the plug on the seat is effected.

5. The plug as claimed in claim 4; wherein: the fluid communication device includes a fluid communication control valve and a fluid communication passage; the fluid communication control valve is configured for displacement relative to the fluid communication passage for effecting opening of the fluid communication passage such that the fluid communication between the housing passage of the flow control apparatus and the pusher is effected.

6. The plug as claimed in claim 5, further comprising: a valve actuator configured for effecting the displacement of the fluid communication control valve for effecting the opening of the fluid communication passage.

7. The plug as claimed in claim 6; wherein the displacement of the fluid communication control valve is effectible by the valve actuator in response to the sensing of a trigger.

8. The plug as claimed in claim 6 or 7; wherein the valve actuator includes a gas generator.

9. The plug as claimed in any one of claims 1 to 8; the seat-engaging member is displaceable, when the seat-engaging member is disposed in the seating-ready condition and becomes aligned with the seat while the plug is being conducted through the housing passage, in a lateral direction relative to the longitudinal axis of the housing passage by the applied force being transmitted by the seating actuator to the seat-engaging member, such that the engagement of the seat-engaging member with the seat is effected by the lateral displacement of the seat-engaging member.

10. The plug as claimed in claim 9; wherein the seat-engaging member is positionable relative to an external surface of the plug such that, when the seat-engaging member becomes laterally displaced such that the seat-engaging member is engaged to the seat, the seat-engaging member is recessed into the external surface of the plug such that opposition to conduction of the plug through the housing passage in a downhole direction is effected and such that the seating of the plug on the seat is effected.

1 1. The plug as claimed in claim 10; wherein: the recessing of the seat-engaging member into the external surface of the plug is into a recess of the plug, wherein the recess defines a shoulder; the pusher includes a plurality of teeth having inclined cam surfaces; and the seat-engaging surface includes a plurality of teeth having inclined follower surfaces corresponding to the cam surfaces and matingly engaging the teeth of the pusher such that, while the pusher is transmitting the applied force to the seat-engaging member, and when the seat- engaging member becomes aligned with the seat, the cam surfaces progressively advance against the follower surfaces, and the shoulder co-operates with the seat-engaging member while the cam surfaces progressively advance against the follower surfaces such that the lateral displacement of the seat-engaging member into the engagement with the seat is effected and such that the seating of the plug on the seat is effected.

12. A kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a flow control apparatus including: a housing; a port disposed within the housing; a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port; a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port; and a seat; a trigger; and a plug including: a seat-engaging member that is deployable to a seating-ready condition such that the seat- engaging member is disposed for becoming displaced into engagement with the seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat- engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; and a seating actuator for effecting transmission of an applied force to the seat-engaging member, in response to the sensing of the trigger, for effecting the disposition of the seat- engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat.

13. The kit as claimed in claim 12; wherein the plug is further configured such that, when the flow control apparatus and the trigger are integrated within a wellbore string such that the trigger is disposed uphole relative to the seat of the flow control apparatus, the plug is deployable to the seating-ready conduction while being conducted in a downhole direction through the wellbore string and prior to becoming aligned with the seat of the flow control apparatus.

14. The kit as claimed in claim 12 or 13; wherein the flow control apparatus includes the trigger.

15. The kit as claimed in any one of claims 12 to 14; wherein the plug includes a sensor for sensing the trigger.

16. A kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a first flow control apparatus including: a first housing; a first port disposed within the first housing; a first flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the first port; a first housing passage extending through the first housing and, while the first port is disposed in the open condition, disposed in fluid communication with the first port; and a first seat; a second flow control apparatus including: a second housing; a second port disposed within the second housing; a second flow control member displaceable relative to the second port from a closed position to an open position, for effecting opening of the second port; a second housing passage extending through the second housing and, while the second port is disposed in the open condition, disposed in fluid communication with the second port; and a second seat; a third flow control apparatus including: a third housing; a third port disposed within the third housing; a third flow control member displaceable relative to the third port from a closed position to an open position, for effecting opening of the third port; a third housing passage extending through the third housing and, while the third port is disposed in the open condition, disposed in fluid communication with the third port; and a third seat; a first trigger; and a second trigger; a first plug including: a first seat-engaging member that is deployable to a seating-ready condition such that the first seat-engaging member is disposed for becoming displaced into engagement with the first seat of the first flow control apparatus when, while the first plug is being conducted through the first housing passage, the first seat-engaging member becomes aligned with the first seat, wherein the engagement of the first seat-engaging member with the first seat is such that the first plug becomes seated on the first seat such that establishment of a first displacement-actuating pressure differential is effectible across the first plug for effecting the displacement of the first flow control member of the first flow control apparatus from the closed position to the open position; and a first seating actuator for effecting transmission of an applied force to the first seat- engaging member, in response to the sensing of the first trigger, for effecting the disposition of the first seat-engaging member in the seating-ready condition; wherein, while the first seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the first seating actuator to the first seat-engaging member, and when the first seat-engaging member becomes aligned with the first seat, the applied force effects the displacement of the first seat-engaging member into the engagement with the first seat. a second plug including: a second seat-engaging member that is deployable to a seating-ready condition such that the second seat-engaging member is disposed for becoming displaced into engagement with the second seat of the second flow control apparatus when, while the second plug is being conducted through the second housing passage, the second seat-engaging member becomes aligned with the second seat, wherein the engagement of the second seat-engaging member with the second seat is such that the second plug becomes seated on the second seat such that establishment of a second displacement-actuating pressure differential is effectible across the second plug for effecting the displacement of the second flow control member of the second flow control apparatus from the closed position to the open position; a second seating actuator for effecting transmission of an applied force to the second seat- engaging member, in response to the sensing of the second trigger, for effecting the disposition of the second seat-engaging member in the seating-ready condition; wherein, while the second seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the second seating actuator to the second seat-engaging member, and when the second seat-engaging member becomes aligned with the second seat, the applied force effects the displacement of the second seat-engaging member into the engagement with the second seat. wherein each one of the first plug and the second plug, independently, is co-operatively configured with the first, second and third flow control apparatuses, and the first and second triggers such that, when the first, second and third flow control apparatuses, and the first and second triggers, are integrated into a wellbore string such that the second flow control apparatus is disposed uphole relative to the first flow control apparatus, the third flow control apparatus is disposed uphole relative to the second flow control apparatus, the first trigger is positioned uphole relative to the first seat and downhole relative to the second seat, and the second trigger is positioned uphole relative to the second seat and downhole relative to the third seat: the first plug is conductible past the third flow control apparatus and the second flow control apparatus, in sequence, while being conducted in a downhole direction through the wellbore string; and the second plug is conductible past the third flow control apparatus while being conducted in a downhole direction through the wellbore string.

17. The kit as claimed in claim 16; and wherein each one of the first plug and the second plug, independently, is further cooperatively configured with the first, second and third flow control apparatuses, and the first and second triggers such that, when the first, second and third flow control apparatuses, and the first and second triggers, are integrated into a wellbore string such that the second flow control apparatus is disposed uphole relative to the first flow control apparatus, the third flow control apparatus is disposed uphole relative to the second flow control apparatus, the first trigger is positioned uphole relative to the first seat and downhole relative to the second seat, and the second trigger is positioned uphole relative to the second seat and downhole relative to the third seat: the first plug is deployable to the seating-ready conduction while being conducted in a downhole direction through the wellbore string, prior to becoming aligned with the first seat of the first flow control apparatus but after having been conducted past both of the second and third seats; and the second plug is deployable to the seating-ready conduction while being conducted in a downhole direction through the wellbore string, prior to becoming aligned with the second seat of the second flow control apparatus but after having been conducted past the third seat.

18. The kit as claimed in claim 16 or 17; wherein the first plug is deployable to the seating-ready condition from a non-interference condition, wherein, in the non-interference condition, the first plug is disposed such that, while the plug is being conducted in a downhole direction through a wellbore string including the third flow control apparatus and the second flow control apparatus, wherein the third flow control apparatus is disposed uphole relative to the second flow control apparatus, the first plug is conductible past the third flow control apparatus and the second flow control apparatus, in sequence, while being conducted in a downhole direction through the wellbore string.

19. The kit as claimed in any one of claims 16 to 18; wherein the first plug is further configured to ignore the second trigger.

20. The kit as claimed in claim 19; wherein the ignoring of the second trigger by the first plug is such that, when the first, second and third flow control apparatuses, and the first and second triggers, are integrated into a wellbore string such that the second flow control apparatus is disposed uphole relative to the first flow control apparatus, the third flow control apparatus is disposed uphole relative to the second flow control apparatus, the first trigger is positioned uphole relative to the first seat and downhole relative to the second seat, and the second trigger is positioned uphole relative to the second seat and downhole relative to the third seat, the first plug is conductible past the second trigger such that there is an absence of deployment of the first plug to the seating-ready condition, such that the first plug is conductible past the second flow control apparatus while being conducted in a downhole direction within the wellbore string.

21. The kit as claimed in claim 19; wherein the ignoring of the second trigger by the first plug is such that, when the first, second and third flow control apparatuses, and the first and second triggers, are integrated into a wellbore string such that the second flow control apparatus is disposed uphole relative to the first flow control apparatus, the third flow control apparatus is disposed uphole relative to the second flow control apparatus, the first trigger is positioned uphole relative to the first seat and downhole relative to the second seat, and the second trigger is positioned uphole relative to the second seat and downhole relative to the third seat, the first plug is conductible past the second trigger such that, when the first seat-engaging member becomes aligned with the second seat, there is a failure of engagement of the first-engaging member to the second seat such that the first plug fails to seat on the second seat while being conducted in a downhole direction within the wellbore string.

22. The kit as claimed in claim 19; wherein the ignoring of the second trigger by the first plug is such that, when the first, second and third flow control apparatuses, and the first and second triggers, are integrated into a wellbore string such that the second flow control apparatus is disposed uphole relative to the first flow control apparatus, the third flow control apparatus is disposed uphole relative to the second flow control apparatus, the first trigger is positioned uphole relative to the first seat and downhole relative to the second seat, and the second trigger is positioned uphole relative to the second seat and downhole relative to the third seat, the first plug is conductible past the second trigger such that there is an absence of deployment of the first plug to the seating-ready condition such that, when the first seat-engaging member becomes aligned with the second seat, there is a failure of engagement of the first-engaging member to the second seat such that the first plug fails to seat on the second seat, such the first plug is conductible past the second flow control apparatus while being conducted in a downhole direction within the wellbore string.

23. The kit as claimed in any one of claims 16 to 22; wherein the third flow control apparatus includes the second trigger; and wherein the second flow control apparatus includes the first trigger.

24. The kit as claimed in any one of claims 16 to 23; wherein the first plug includes a sensor for sensing the first trigger; and wherein the second plug includes a sensor for sensing the second trigger;

25. The kit as claimed in any one of the claims 16 to 24; wherein the size of the second plug is greater than, equal to, or substantially equal to the size of the second plug.

26. A method of injecting treatment material into a subterranean reservoir via a wellbore string, wherein the wellbore string includes first, second and third flow control apparatuses, wherein the second flow control apparatus is disposed uphole relative to the first flow control apparatus, and the third flow control apparatus is disposed uphole relative to the second flow control apparatus, wherein each one of the flow control apparatuses, independently, includes a housing, a port disposed within the housing, a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port, a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port, and a seat configured for seating a plug such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member from the closed position to the open position, comprising: conducting a first plug in a downhole direction through the wellbore string, including: conducting the first plug through the third flow control apparatus without having effected seating of the first plug on the seat of the third flow control apparatus; after having conducted the first plug through the third flow control apparatus, conducting the first plug through the second flow control apparatus without having effected seating of the first plug on the seat of the second flow control apparatus; after having conducted the first plug through the second flow control apparatus, conducting the first plug through the first control apparatus such that the first plug becomes seated on the seat of the first flow control apparatus; after having seated the first plug on the seat of the first flow control apparatus, conducting a second plug in a downhole direction through the wellbore string, including: conducting the second plug through the third flow control apparatus without having effected seating of the second plug on the seat of the third flow control apparatus; after having conducted the second plug through the third flow control apparatus, conducting the second plug through the second control apparatus such that the second plug becomes seated on the seat of the second flow control apparatus; wherein the size of the second plug is greater than, equal to, or substantially equal to the size of the second plug.

27. The method as claimed in claim 26; further comprising: after having seated the first plug on the seat of the first flow control apparatus, and prior to conducting a second plug in a downhole direction through the wellbore string: establishing a displacement-actuating pressure differential across the first plug for effecting the displacement of the flow control member of the first flow control apparatus from the closed position to the open position such that the opening of the port of the first flow control apparatus is effected; injecting a fluid treatment through the port of the first flow control apparatus.

28. The method as claimed in claim 27; further comprising: after having seated the second plug on the seat of the second flow control apparatus: establishing a displacement-actuating pressure differential across the second plug for effecting the displacement of the flow control member of the second flow control apparatus from the closed position to the open position such that the opening of the port of the second flow control apparatus is effected; and injecting a fluid treatment through the port of the second flow control apparatus.

29. The method as claimed in any one of claims 26 to 28, further comprising: after having conducted the first plug through the second flow control apparatus, and prior to seating the first plug becomes on the seat of the first flow control apparatus, actuating the first plug such that the first plug becomes disposed for seating on the seat of the first flow control apparatus; and after having conducted the second plug through the third flow control apparatus, and prior to seating the second plug on the seat of the second flow control apparatus, actuating the second plug such that the second plug becomes disposed for seating on the seat of the second flow control apparatus.

30. A plug including: a seat-engaging member for engaging a seat of a flow control apparatus within a wellbore such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; a dissolvable closure occluding a passage; wherein the dissolvable closure is configured to dissolve in wellbore fluid such that fluid communication is effected within the wellbore between a wellbore portion that is disposed uphole relative to the plug and a wellbore portion is disposed downhole relative to the plug.

31. A kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a flow control apparatus including: a housing; a port disposed within the housing; a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port, wherein the flow control member includes grooves; a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port; and a seat; and a plug including: a seat-engaging member that is deployable to a seating-ready condition such that the seat- engaging member is disposed for becoming displaced into engagement with the seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat- engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; a seating actuator for effecting transmission of an applied force to the seat-engaging member for effecting the disposition of the seat-engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat. wherein the seat-engaging member is configured, when seated on the seat, to key into the grooves of the seat such that interference to rotation of the plug, relative to the axis of the passage, is effected, during milling out of the plug by a milling tool.

32. A kit for constructing a system for injecting treatment material into a subterranean reservoir comprising: a flow control apparatus including: a housing; a port disposed within the housing; a flow control member displaceable relative to the first port from a closed position to an open position, for effecting opening of the port, wherein the flow control member includes grooves; a housing passage extending through the housing and, while the port is disposed in the open condition, disposed in fluid communication with the port; and a seat; and a plug including: a seat-engaging member that is deployable to a seating-ready condition in response to sensing of the trigger such that the seat-engaging member is disposed for becoming displaced into engagement with the seat of the flow control apparatus when, while the plug is being conducted through the housing passage, the seat-engaging member becomes aligned with the seat, wherein the engagement of the seat-engaging member with the seat is such that the plug becomes seated on the seat such that establishment of a displacement-actuating pressure differential is effectible across the plug for effecting the displacement of the flow control member of the flow control apparatus from the closed position to the open position; a seating actuator for effecting transmission of an applied force to the seat-engaging member for effecting the disposition of the seat-engaging member in the seating-ready condition; wherein, while the seat-engaging member is disposed in a seating-ready condition, the applied force is being transmitted by the seating actuator to the seat-engaging member, and when the seat-engaging member becomes aligned with the seat, the applied force effects the displacement of the seat-engaging member into the engagement with the seat. wherein the plug includes a downhole portion, defining a downhole end, and an uphole portion defining an uphole end, wherein the downhole end includes a locking member configured to key into an uphole end of another identical, or substantially identical plug, wherein the downhole and uphole portions are co-operatively configured such that, while the seat-engaging member is seated on the seat, the seat-engaging member is retained between the downhole and uphole portions such that, after the seat-engaging member has been milled out by a milling tool, the downhole portion is pushed, by the milling tool, downhole to a plug that is disposed immediately downhole, and the locking member keys into the uphole end of such plug so as to interfere with rotation of the downhole portion during milling of the downhole portion by the milling tool.