Patent Publication Number: US-10781664-B2

Title: Plug-actuated flow control member

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of and claims priority under 35 U.S.C. § 120 from U.S. patent application Ser. No. 15/136,000 filed Apr. 22, 2016, now U.S. Pat. No. 10,161,220, which itself claims priority to U.S. Provisional Patent Application No. 62/152,603 filed Apr. 24, 2015. The contents of each of these documents are incorporated herein by reference in their entirety. 
    
    
     FIELD 
     The present disclosure relates to downhole tools which are deployable within a wellbore for controlling supply of treatment fluid to the reservoir. 
     BACKGROUND 
     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. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The preferred embodiments will now be described with the following accompanying drawings, in which: 
         FIG. 1  is a schematic illustration of an embodiment of a system deployed within a wellbore, and employing first and second downhole tools; 
         FIG. 2  is a sectional side elevation view of a first downhole tool; 
         FIG. 3  is a detailed view of Detail “B” in  FIG. 2 ; 
         FIG. 4  is a detailed view of Detail “A” in  FIG. 2 ; 
         FIG. 5  is another sectional side elevation view of the first downhole tool, with the plug and the biasing member removed for clarity; 
         FIG. 6  is a side elevation view of an embodiment of a plug for use with the first downhole tool; 
         FIG. 7  is an end view of one end of the plug of  FIG. 6 ; 
         FIG. 8  is a side sectional elevation view of the plug of  FIG. 6 , taken along lines B-B in  FIG. 7 ; 
         FIG. 9  is a top perspective fragmentary view of the first downhole tool, with the housing removed for clarity; 
         FIG. 10  is a sectional side elevation view of a second downhole tool; 
         FIG. 11  is a detailed view of Detail “B” in  FIG. 10 ; 
         FIG. 12  is a detailed view of Detail “A” in  FIG. 10 ; and 
         FIGS. 13 to 17  illustrate the various positions of the plug as it is being conducted downhole through the first downhole tool that is disposed within a wellbore. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , there is provided a downhole tool  100  for effecting selective stimulation of a subterranean formation  14 , such as a reservoir  16 . The downhole tool  100  is deployable within a wellbore  10 . Suitable wellbores  10  include vertical, horizontal, deviated or multi-lateral wells. 
     The stimulation is effected by supplying treatment material to the subterranean formation which may include a hydrocarbon-containing reservoir. 
     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. 
     In some embodiments, for example, the treatment material includes water, and is supplied to effect waterflooding of the reservoir. 
     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. 
     The downhole tool  100  may be deployed within the wellbore  10  and integrated within a wellbore string  20  that is disposed within the wellbore  10 . Integration may be effected, for example, by way of threading or welding. 
     The wellbore string  20  may include pipe, casing, or liner, and may also include various forms of tubular segments, such as downhole tools described herein. 
     Successive downhole tools  100  may be spaced from each other within the wellbore string  20  such that each downhole tool  100  is positioned adjacent a producing interval to be stimulated by fluid treatment effected by treatment material that may be supplied through a port  106  (see below). 
     Referring to  FIG. 2 , in some embodiments, for example, the downhole tool  100  includes a housing  102 . In some embodiments, for example, the housing  102  includes interconnected top sub  102 A, outer housing  102 B, and bottom sub  102 C. 
     The housing  102  is coupled (such as, for example, threaded) to the wellbore string  20 . 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 wellbore string may include multiple segments, and segments may be connected (such as by a threaded connection). 
     A passage  104  is defined within the housing  102 . The passage  104  is configured for conducting treatment material from a supply source (such as at the surface) to a port  106  that is also defined within and extends through the housing  102 . 
     The housing  102  includes a sealing surface configured for sealing engagement with a flow control member  108  (see below). In some embodiments, for example, the sealing surface is defined by sealing members  110 A,  110 B. In some embodiments, for example, when a flow control member  108  is disposed in a position (the “closed position”, see below) corresponding to the closed condition of the port  106 , each one of the sealing members  110 A,  110 B, is, independently, disposed in sealing, or substantially sealing, engagement with both of the housing  102  and the flow control member  108 . The sealing, or substantially sealing, engagement effects sealing, or substantial sealing, of fluid communication between the passage  104  and the port  106  (and thereby the wellbore, and, therefore, the subterranean formation  14 ). 
     Referring to  FIG. 2 , in some embodiments, for example, each one of the sealing members  110 A,  110 B, 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  110 A,  110 B, 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). 
     The port  106  extends through the housing  102 , and is disposed between the sealing surfaces  110 A,  110 B. 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 wellbore  10 . In this respect, during treatment, treatment material being conducted from the treatment material source via the passage  104  is supplied to the wellbore  10  through the port  106 . 
     In some embodiments, for example, it is desirable for the treatment material, being supplied to the wellbore  10  through the port  106 , be supplied, or at least substantially supplied, within a definite zone (or “interval”) of the subterranean formation in the vicinity of the port  106 . In this respect, the system may be configured to prevent, or at least interfere, with conduction of the treatment material, that is supplied to one zone of the subterranean formation, to a remote zone of the subterranean formation. In some embodiments, for example, such undesired conduction to a remote zone of the subterranean formation may be effected 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 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. 
     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 mm 2 /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. 
     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. 
     In some embodiments, for example, the downhole tool  100  includes the flow control member  108 , and the flow control member  108  is positionable, relative to the housing  102 , in open and closed positions. 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 . 
     In some embodiments, for example, the flow control member  108  includes a sleeve. The sleeve is slideably disposed within the passage  104 . 
     While the downhole tool  100  is disposed within the wellbore  10 , in the open position, the flow control member  108  is disposed in the closed position, and disposition of the flow control member  108  in the first position is such that the port  106  is closed. 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  effects uncovering of the port  106 . In some embodiments, for example, the port  106  is closed, the flow control member  108  prevents, or substantially prevents, fluid flow through the port  106 , between the passage  104  and the wellbore  10 . 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 , and across the port  106 , is being conducted through the port  106 . 
     The flow control member  108  may be displaced from the closed position to the open position and thereby effect opening of the port  106 . Such displacement is effected while the downhole tool  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 fluid, that is being supplied from the surface, to be discharged through the port  106 . 
     In some embodiments, for example, the flow control member  108  co-operates with the sealing members  110 A,  110 B 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 surfaces  110 A,  110 B, and preventing, or substantially preventing, fluid flow from the passage  104  to 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 surface  110 A), thereby providing a passage  104  for treatment material to be delivered to the port  106  from the passage  104 . 
     The flow control member  108  is configured for displacement, relative to the port  106 , from the closed position to the open position in response to application of a sufficient net opening force. When the flow control member  108  is disposed in the closed position, the port  106  is disposed in the closed condition. When the flow control member  108  is disposed in the open position, the port  106  is disposed in an open condition. In some embodiments, for example, the application of a sufficient net opening force is effected by a fluid pressure differential (see below). 
     In some embodiments, for example, the housing  102  includes an inlet  112 . When the port  106  is disposed in the open condition, fluid communication is effected between the inlet  112  and the port  106  via the passage  104 . When the port  106  is disposed in the closed condition, sealing, or substantial sealing, of fluid communication, between the inlet  112  and the port  106  is effected. 
     In some embodiments, for example, a flow control member-engaging collet  140  extends from the housing  102  (and, specifically, the bottom sub  102 C), and is configured to releasably engage the flow control member  108  for resisting a change in position of the flow control member  108 . In this respect, in some embodiments, for example, the flow control member-engaging collet  140  includes at least one collet finger  140 A, and each one of the at least collet finger  140   a  includes tabs  1401   a ,  1401   b  that engages the flow control member  108 . 
     In some embodiments, for example, the flow control member  108  and the flow control member-engaging collet  140  are co-operatively configured so that engagement of the flow control member  108  and the flow control member-engaging collet  140  is effected while the flow control member  108  is disposed in the closed position (the engagement is with the tab  1401   a ) and also when the flow control member  108  is disposed in the open position (in which case the engagement is with the tab  1401   b ). In this respect, while the flow control member  108  is disposed in the closed position, the flow control member-engaging collet  140  is engaging the flow control member  108  such that interference or resistance is being effected to a change in position of the flow control member  108  from the closed position to the open position. In some embodiments, for example, the engagement is such that the flow control member-engaging collet  140  is retaining the flow control member  108  in the closed position, and a sufficient net opening force is required to be applied to the flow control member  108  to release the flow control member  108  from retention by the flow control member-engaging collet  140  and thereby effect opening of the flow control member  108 . Also in this respect, while the flow control member  108  is disposed in the open position, the flow control member-engaging collet  140  is engaging the flow control member  108  such that interference or resistance is being effected to a change in position of the flow control member  108  from the open position to the closed position. In some embodiments, for example, the engagement is such that the collet  140  is retaining the flow control member  108  in the open position, and a sufficient net closing force is required to be applied to the flow control member  108  to release the flow control member  108  from retention by the flow control member-engaging collet  140  and thereby effect closing of the flow control member  108 . In this respect, the flow control member-engaging collet  140  mitigates inadvertent opening and closing of the flow control member  108 . 
     The housing  102  additionally defines a shoulder  142  to limit downhole displacement of the flow control member  108 . 
     The flow control member  108  is configured for displacement, relative to the port  106 , in response to application of a sufficient net force effected by a fluid pressure differential that has been created across the flow control member  108 . In some embodiments, for example, the fluid pressure differential is created by supplying the passage  104  with pressurized fluid while a plug  116  is co-operatively disposed within the passage  104  relative to the flow control member  108 , such that the created pressure differential is that which is created across the plug  116 . In some embodiments, for example, the plug  116  is deployed in sealing, or substantially sealing, engagement with the flow control member  108 , such that fluid communication between an uphole space  104   a  of the fluid passage  104  and a downhole space  104   b  of the fluid passage  104  is sealed or substantially sealed, and such that supplying of the pressurized fluid to the passage  104 , uphole of the plug  116 , effects the creation of a pressure differential across the plug  116  and also, therefore, between the uphole and downhole spaces  104   a ,  104   b , and such created pressure differential effects application of a net force to the flow control member  108  that is sufficient to urge displacement of the flow control member  108  in a downhole direction (in this case, to effect opening of the port  106 ). 
     The plug  116  is fluid conveyable, and may take the form of any shape, such as, for example, a ball or a dart. 
     In some embodiments, for example, the pressure differential is effected by deploying a plug  116  into the passage  104  such that the plug  116  becomes co-operatively disposed within the passage  104 , relative to the flow control member  108 , for effecting creation of the pressure differential, while the pressurized fluid is being supplied into the passage  104  uphole of the plug  116 . In some embodiments, for example, the pressure differential is effected while the plug  116  is sealingly, or substantially sealingly, disposed within the passage  104 . In this respect, while the plug is sealingly, or substantially sealingly, disposed within the first passage  104 , and while pressurized fluid is being supplied into the passage  104 , uphole of the plug  116 , fluid flow, past the first plug, in a downhole direction, is prevented, or substantially prevented, such that the creation of the fluid pressure differential, for effecting the displacement of the first flow control member, is effected. In this respect, in some embodiments, for example, a portion of the external surface of the plug  116  is defined by a resilient material. In the illustrated embodiment, the resilient material is in the form of fins  116   a . The fins  116   a  function to enable the plug to be conducted downhole through the wellbore string  20 , while enabling the sealing, or substantially sealing, disposition of the plug  116  relative to the passage-defining surface  102   a  of the housing  102 . 
     The co-operative disposition of the plug  116  within the passage  104 , relative to the flow control member  108 , is effected by a seat  118 . In this respect, the seating of the plug  116  on the seat  118  effects the co-operative disposition of the plug  116  within the passage  104 , relative to the flow control member  108 , such that, upon supplying of pressurized fluid to the passage  104 , uphole of the seated plug  116 , the pressure differential is created that effects application of the net force to the flow control member  108  that is sufficient to urge the flow control member  108  into displacement from the closed position to the open position. 
     Amongst other things, in order to avoid the use of different sized plugs for effecting fluid treatment of multiple stages through ports whose manner of opening is as above-described, the seat  118 , upon which the plug  116  is seated for assuming co-operative disposition relative to the respective flow control member  108 , is configured so as to be selectively deployable to a plug-receiving position for receiving a plug  116  being deployed through the passage  104 . In this respect, when not so deployed, the seat  116  is disposed in a non-interference position relative to the passage  104 , thereby permitting other plugs to be selectively deployed further downhole to effect fluid treatment of zones within the subterranean formation that are disposed further downhole. 
     In this respect, and referring to  FIG. 5 , the downhole tool  100  further includes a key profile  120 . The key profile  120  effects actuation (such as, for example, by unlocking) of the seat  118  to the plug-receiving position in response to registration of the key profile  120  with a matching key  122  of the plug  116  being deployed through the passage  104 . In some embodiments, for example, the key profile  120  includes a pattern that corresponds to the matching key  122  of the plug  116  being deployed through the passage  104 . When the key profile  120  matches a key  122  of a plug  116  (see  FIGS. 6 to 8 ) being conducted through the wellbore string  20  (including through the passage  104 ), such that the key  122  registers with the key profile  120 , the key profile  120  effects the deployment of the seat  118 , and the deployment is effected downhole of the key profile  120  and within sufficient time such that the seat  118  is deployed prior to the plug  116  (having the matching key  122 ) having reached the position within the passage  104  at which the seat  118  becomes deployed. In this respect, the deployed seat  118  catches the plug  116  such that the seat  116  becomes seated on the seat  118 . When the key profile  120  does not match a key  122  of a plug  116 , then the actuation is not effected, and the plug  116  continues passing downhole, and, in some embodiments, to the next downhole tool, disposed further downhole, relative to the downhole tool  100  (where matching of the key profile  120  to the key  122  of the plug  116  was not successful). 
     Referring to  FIG. 3 , in some embodiments, for example, the seat  118  is retained in an undeployed position (in a position of non-interference with respect to the passage  104 , such that a plug  116 , being conducted downhole, is permitted to pass the seat  118 , in the undeployed position, and proceed downhole relative to the seat  118 ), and the actuation of the seat  118  to the plug-receiving position includes releasing of the seat  118  from such retention. In this respect, in some embodiments, for example, the seat  118  is retained in the undeployed position by a tie pin  134  (see  FIG. 9 ). In some embodiments, for example, the seat  118  is in the form of a plurality of seat pins  118   a  that are extendible to the plug-receiving position through corresponding apertures  108   a  provided in the flow control member  108 , and the tie pin  134  extends through each one of the seat pins  118   a  and encircles the flow control member  108 . In some embodiments, retention of the seat  118  in the undeployed position is also maintained by positioning the seat  118 , in the undeployed position, immediately next to an internal surface of the housing  102 , thereby maintaining the seat pins  118   a  in position for being actuated into deployment by the seat actuator  124  (see below), which, in concert, effects the shearing of the tie pin  134 . 
     Referring to  FIG. 4 , in some embodiments, for example, the downhole tool  100  further includes a seat actuator  124  and a seat actuator retainer  126 . The seat actuator  124  functions to effect deployment of the seat  118 . In the illustrated embodiment, the seat actuator  124  is in the form of a sleeve. The seat actuator retainer  126  functions to retain the seat actuator  124  until the key profile  120  matches the key  122  of a plug  116  that is passing by the key profile  120  while being conducted downhole through the wellbore string  20 . In the illustrated embodiment, the flow control member  108  also functions as the seat actuator retainer  126 . In response to the matching of the key  122  with the key profile  120 , the seat actuator  124  is released from retention by the seat actuator retainer  126 , such that the seat actuator  124  effects the deployment of the seat  118 . 
     In some embodiments, for example, the seat actuator  124  is biased towards a seat actuation position for urging the deployment of the seat  118 . In this respect, upon the releasing of the seat actuator  124  from retention by the seat actuator retainer  126 , the biasing effects the displacement of the seat actuator  124  to the seat actuation position such that the deployment of the seat  118  is effected. In some embodiments, for example, the biasing is effected by a biasing member  162 , such as a compressed spring stack that is housed within a space  127  between the flow control member  108  (in region  108   b , see  FIG. 9 ) and an internal surface of the housing  102 , and is pressing against the seat actuator  124 . 
     Referring to  FIGS. 4 and 9 , in some embodiments, for example, the seat actuator  124  includes one or more retainable portions  124   a ,  124   b ,  124   c .  124   d  (four are shown). The registration of the matching key  122  with the key profile  120  effects relative displacement between: (i) all of the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d , and (ii) the seat actuator retainer  126 . The relative displacement is such that the releasing of the seat actuator  124  from retention by the seat actuator retainer  126  is effected, such that the seat actuator  124  becomes displaceable to the seat actuation position for effecting the deployment of the seat  118  to the plug-receiving position for receiving a plug  116  being deployed through the passage  104 . In some embodiments, for example, the releasing of all of the retainable portions  124   a ,  124   b ,  124   c .  124   d  is effected simultaneously or substantially simultaneously. 
     In some embodiments, for example, each one of the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d  independently, is displaceable between a retained position and a released position. For each one of the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d , in the retained position, the retainable portion is retained by the seat actuator retainer  126 . In the released position, the retainable portion is released from the seat actuator retainer  126 . 
     In this respect, the deployment of the seat  118  is prevented by the retention of at least one of the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d  by the seat actuator retainer  126 . In other words, retention of only one of the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d  is sufficient for the seat actuator  124  to be prevented from effecting deployment of the seat  118 . In this respect also, the seat actuator  124  becomes released from retention by the seat actuator retainer  126 , and becomes displaceable to effect the deployment of the seat  118  once all of the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d  become disposed in their respective released positions. 
     In some embodiments, for example, each one of the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d , independently, is biased towards its respective retained position. In some embodiments, for example, each one of the retainable portions  124   a ,  124   b ,  124   c .  124   d , independently, is integral to corresponding leaf spring portions  130   a ,  130   b ,  130   c ,  130   d  that have been formed from the cutting of a portion of the seat actuator  124 . In the illustrated embodiments, for example, each one of retainable portions  124   a ,  124   b .  124   c ,  124   d  is in the form of a pin that is attached to the top surface of the seat actuator  124 . In order for all of the retainable portions  124   a ,  124   b ,  124   c .  124   d  to be displaced to their respective released positions, it is necessary to apply sufficient force to the retainable portions  124   a ,  124   b ,  124   c .  124   d  to effect displacement to their respective released positions. In this respect, the key profile  120  is configured to transmit, to the one or more retainable portions  124   a ,  124   b ,  124   c .  124   d , a force applied by the plug  116  while the registration of the matching key  122  with the key profile  120  is being effected, where such force is sufficient to effect displacement of the retainable portions  124   a ,  124   b ,  124   c .  124   d  to their respective released positions. In order to maintain the key profile  120  in a position for registering with a matching key  122  of a plug  116  being deployed through the wellbore string  20 , the key profile  120  is biased towards this position. In this respect, in some embodiments, for example, the biasing of the retainable portions  124   a ,  124   b ,  124   c .  124   d  also effects the biasing of the key profile  120  into a position for registering with a matching key  122  of a plug  116  being deployed through the wellbore string  20 . 
     In some embodiments, for example, the downhole tool  100  includes a releasing actuator  132 . The releasing actuator  132  including a plurality of releasing actuator members  132   a ,  132   b ,  132   c ,  132   d . In the illustrated embodiments, each one of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d  is in the form of pins. Each one of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d , independently, corresponds to a respective one of the retainable portions  124   a ,  124   b ,  124   c .  124   d . As discussed above, each one of the retainable portions  124   a ,  124   b ,  124   c .  124   d , independently, is displaceable between the retained position and the released position. Each one of the retainable portions  124   a ,  124   b ,  124   c .  124   d , independently, is displaceable from its respective retained position to its respective released position, in response to transmission, by the respective releasing actuator member  132   a ,  132   b ,  132   c ,  132   d , of a force being applied from within the passage to the respective releasing actuator member. Registration of all of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d , with a matching key  122  of a plug  116  being deployed through the wellbore string  20 , results in the receiving of a force, applied by the plug  116 , by each one of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d . Such received force is transmitted by each one of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d  to a respective one of the retainable portions  124   a ,  124   b ,  124   c .  124   d , such that displacement of the respective retainable portion is effected, and such that each one of retainable portions  124   a ,  124   b ,  124   c .  124   d , independently, becomes disposed in its respective released position. In this respect, in some embodiments, for example, the key profile  120  is defined by the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d . In some embodiments, for example, the key profile  120  is defined by the relative spacing between the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d . In this respect, the matching key  122  of the plug  122  includes ribs  122   a ,  122   b ,  122   c ,  122   d  that match with the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d , such that as the plug  122  is conducted past the key profile  120 , the ribs  122   a ,  122   b ,  122   c ,  122   d  register with (such as by engaging) the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d , such that all of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d  are displaced to effect the releasing of all of the retainable portions  124   a ,  124   b ,  124   c .  124   d . In some embodiments, for example, the releasing of all of the retainable portions  124   a ,  124   b ,  124   c .  124   d  is effected simultaneously or substantially simultaneously. This releasing is with effect that the seat actuator  124  becomes released from retention by the seat actuator retainer  126 , such that the seat actuator  124  becomes displaceable to the seat actuation position for effecting the deployment of the seat  118  to the plug-receiving position for receiving a plug  116  being deployed through the passage  104 . In some embodiments, for example, the displacing of all of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d  is effected simultaneously or substantially simultaneously. 
     In some embodiments, for example, and as discussed above with respect to the key profile  120 , the biasing of the retainable portions  124   a ,  124   b ,  124   c .  124   d  also effects the biasing of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d  (the biasing of the retainable portion  124   a  also effects the biasing of the respective releasing actuator member  132   a , etc.) into positions for registering with a matching key  122  of a plug  116  being deployed through the wellbore string  20 . In some embodiments, for example, for each one of the releasing actuator members  132   a ,  132   b ,  132   c ,  132   d , one end extends through passages  108   a ,  108   b ,  108   c ,  108   d  of the flow control member  108 , such that such ends define the key profile  120  and are positioned for registering with a matching key  122  of a plug  116  being deployed through the wellbore string  20 . Similarly, in some embodiments, for example, in their retained positions, the retainable portions  124   a ,  124   b ,  124   c .  124   d  are also disposed within the passages  108   a ,  108   b ,  108   c ,  108   d , such that, in such embodiments, the flow control member  108  functions also as the seat actuator retainer  126 . 
     Referring to  FIGS. 1 and 10 to 12 , a second downhole tool  200  may be incorporated within the wellbore string  20  with the downhole tool  100  (or, the “first downhole tool  100 ”), and disposed uphole relative to the first downhole tool  100 . The second downhole tool  200  includes a seat  218  that is deployable to a plug-receiving position for receiving a second plug  216  being deployed through the wellbore string  20 , which corresponds to the configuration of the first downhole tool  100 . In this respect, parts of the second downhole tool  200  that are alike with parts of the first downhole tool  100  are labelled using the same reference numeral incremented by “100”. With the exception of the key profile, the second downhole tool  200  is identical, or substantially identical, to the first downhole tool  100 . The first key profile  120  of the first downhole tool  100  is co-operatively configured with the second key profile  220  of the second downhole tool  200  such that the key  122  of the first plug  116  matches the first key profile  120  but does not match the second key profile  220  such that the first plug  120  is deployable past the second downhole tool  200  without effecting deployment of the second seat  218 . The first plug is, therefore, conductible further downhole, to the first downhole tool  100 , such that the key  122  of the first plug  116  becomes registered with the first key profile  120 , and thereby effects deployment of the first seat  118  such that the first seat  118  becomes positioned for receiving the first plug  116 , and the first plug  116  becomes seated on the first seat  118  once the first plug  116  reaches the first seat  118 . 
     It is understood that additional downhole tools may be incorporated within the wellbore string  20 , and that such additional downhole tools may be identical, or substantially identical, to the first or second downhole tools  100 ,  200 , with the exception that the key profile of each one of the downhole tools is different. 
     In another aspect, a kit may also be provided, and include the first and second downhole tools  100 ,  200 , and also include the first and second plugs  116 ,  216 . For at least one of the first and second plugs  116 ,  216 , the key  122  ( 222 ) of one plug  116  ( 216 ) does not match the key profile  220  ( 120 ) to which the other plug  216  ( 116 ) is registerable with, such that, for at least one of the first and second plugs  116 ,  216 , the plug  116  ( 216 ) is deployable through the passage  204  ( 104 ) of the downhole tool  200  ( 100 ) with the non-matching key profile  220  ( 120 ) without effecting deployment of the seat  218  ( 118 ) of the downhole tool  200  ( 100 ) with the non-matching key profile  220  ( 120 ). It is understood that additional downhole tools may be incorporated within the kit, and that such additional downhole tools may be identical, or substantially identical, to the first or second downhole tools  100 ,  200 , with the exception that the key profile of each one of the downhole tools is different. 
     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 downhole tool apparatus  100 , will now be described. 
     The first plug  116  is conducted downhole (such as being pumped with flowing fluid) through the wellbore string  20  including the first and second downhole tools  100 ,  200 , as described above (see  FIG. 13 ). The plug  116  passes the downhole tool  200 , and, eventually, the plug  116  reaches a position such that the plug key  122  matches the profile  120  (see  FIG. 14 ), thereby effecting deployment of the first seat  114  (see  FIG. 15 ). The plug  116  continues being conducted further downhole until it lands onto the deployed seat  118  (see  FIG. 16 ). Importantly, the first plug  116  has passed the downhole tool  200  without having effected deployment of the second seat  218 . Pressurized fluid is supplied uphole of the seated first plug  116  such that the first flow control member  108  becomes displaced to the open position (see  FIG. 17 ). Treatment fluid is then supplied to the subterranean formation through the first port  106 . The second plug  216  is then conducted downhole (such as being pumped with flowing fluid) through the wellbore string  20 , such that the second seat  218  becomes deployed and the second plug  216  becomes seated on the second seat  218 . Pressurized fluid is then supplied uphole of the seated second plug  216  such that the second flow control member  208  becomes displaced to the open position. Treatment fluid is then supplied to the subterranean formation through the second port  206 . 
     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  116 ,  216  may be drilled out, thereby creating fluid communication between the open ports  106 ,  206  and the wellhead. In other embodiments, for example, the plug  116  may be suitable designed to enable flowback. In this respect, in some embodiments, for example, the plug  116  includes a selectively openable fluid passage  144  for effecting fluid flow within the first passage, across the first plug, in an uphole direction, in response to a downhole fluid pressure, acting on the plug  116 , sufficiently exceeding an uphole fluid pressure, acting on the plug. In some embodiments, for example, the selectively openable fluid passage  144  includes a one-way valve  146 . In the illustrated embodiment, the one-way valve  146  includes a ball that is trapped between a valve seat  148  (upon which the ball is configured to seat as pressurized fluid is being supplied hole of the valve seat  148 ), and a perforated retainer  150 , and is moveable between these two features during flowback. In this respect, such plug  116  enables fluid pressurization, to effect opening of the port  106 , by blocking downhole flow of supplied pressurized fluid, while also enabling flowback of produced hydrocarbon material after the subterranean formation has been treated by the treatment fluid. 
     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.