Patent Publication Number: US-9428999-B2

Title: Multiple zone integrated intelligent well completion

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 13/950,674 filed on 25 Jul. 2013, which is a continuation under 35 USC 120 of International Application No. PCT/US12/57215, filed on 26 Sep. 2012. The entire disclosures of these prior applications are incorporated herein by this reference. 
    
    
     BACKGROUND 
     This disclosure relates generally to equipment utilized and operations performed in conjunction with subterranean wells and, in one example described below, more particularly provides a multiple zone integrated intelligent well completion. 
     Where multiple zones are to be produced (or injected) in a subterranean well, it can be difficult to determine how fluids communicate between an earth formation and a completion string in the well. This can be particularly difficult where the fluids produced from the multiple zones are commingled in the completion string, or where the same fluid is injected from the well into the multiple zones. 
     Therefore, it will be appreciated that improvements are continually needed in the arts of constructing and operating well completion systems. 
     SUMMARY 
     In this disclosure, systems and methods are provided which bring improvements to the arts of constructing and operating well completion systems. One example is described below in which a variable flow restricting device is configured to receive fluid which flows through a well screen. Another example is described below in which an optical waveguide is positioned external to a completion string, and one or more pressure sensors sense pressure internal and/or external to the completion string. 
     A system for use with a subterranean well having multiple earth formation zones is provided to the art by the disclosure below. In one example, the system can include multiple well screens which filter fluid flowing between a completion string in the well and respective ones of the multiple zones, at least one optical waveguide which senses at least one property of the fluid as it flows between the completion string and at least one of the zones, multiple flow control devices which variably restrict flow of the fluid through respective ones of the multiple well screens, and multiple pressure sensors which sense pressure of the fluid which flows through respective ones of the multiple well screens. 
     A completion string for use in a subterranean well is also described below. In one example, the completion string can include at least one well screen, at least one flow control device which selectively prevents and permits substantially unrestricted flow through the well screen, and at least one other flow control device which is remotely operable, and which variably restricts flow through the well screen. 
     Also described below is a method of operating a completion string in a subterranean well. In one example, the method comprises: a) closing all of multiple flow control devices connected in the completion string, the completion string including multiple well screens which filter fluid flowing between the completion string and respective ones of multiple earth formation zones, at least one optical waveguide which senses at least one property of the fluid as it flows between the completion string and at least one of the zones, the multiple flow control devices which variably restrict flow of the fluid through respective ones of the multiple well screens, and multiple pressure sensors which sense pressure of the fluid which flows through respective ones of the multiple well screens; b) at least partially opening a selected one of the flow control devices; and c) measuring a change in the property sensed by the optical waveguide and a change in the pressure of the fluid as a result of the opening of the selected one of the flow control devices. 
     These and other features, advantages and benefits will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the disclosure hereinbelow and the accompanying drawings, in which similar elements are indicated in the various figures using the same reference numbers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a representative partially cross-sectional view of a well system and associated method which can embody principles of this disclosure. 
         FIGS. 2A-C  are representative cross-sectional views of successive longitudinal sections of a completion string which may be used in the well system and method of  FIG. 1 , and which can embody principles of this disclosure. 
         FIG. 3  is a representative cross-sectional view of a section of the completion string, with fluid flowing from an earth formation into the completion string. 
         FIG. 4  is a representative elevational view of another section of the completion string. 
         FIG. 5  is a representative cross-sectional view of another example of the well system and method. 
         FIG. 6  is a representative cross-sectional view of a flow control device which may be used in the well system and method. 
         FIG. 7  is a representative cross-sectional view of a wet connection which may be used in the well system and method. 
         FIG. 8  is a representative cross-sectional view of an expansion joint which may be used in the well system and method. 
     
    
    
     DETAILED DESCRIPTION 
     Representatively illustrated in  FIG. 1  is a well completion system  10  and associated method which can embody principles of this disclosure. However, it should be clearly understood that the system  10  and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible. Therefore, the scope of this disclosure is not limited at all to the details of the system  10  and method described herein and/or depicted in the drawings. 
     In the  FIG. 1  example, a completion string  12  has been installed in a wellbore  14  lined with casing  16  and cement  18 . In other examples, the wellbore  14  could be at least partially uncased or open hole. 
     The completion string  12  includes multiple sets  20  of completion equipment. In some examples, all of the sets  20  of completion equipment can be conveyed into the well at the same time, and gravel  22  can be placed about well screens  24  included in the completion equipment, all in a single trip into the wellbore  14 . 
     For example, a system and technique which can be used for installing multiple sets of completion equipment and gravel packing about well screens of the completion equipment is marketed by Halliburton Energy Services, Inc. of Houston, Tex. USA as the ENHANCED SINGLE TRIP MULTI-ZONE™ system, or ESTMZ™. However, other systems and techniques may be used, without departing from the principles of this disclosure. 
     Packers  26  are used to isolate multiple earth formation zones  28  from each other in the wellbore  14 . The packers  26  seal off an annulus  30  formed radially between the completion string  12  and the wellbore  14 . 
     Also included in each set  20  of completion equipment is a flow control device  32  and a hydraulic control device  34  which controls hydraulic actuation of the flow control device. A suitable flow control device, which can variably restrict flow into or out of the completion string  12 , is the infinitely variable interval control valve IV-ICV™ marketed by Halliburton Energy Services, Inc. A suitable hydraulic control device for controlling hydraulic actuation of the IV-ICV™ is the surface controlled reservoir analysis and management system, or SCRAMS™, which is also marketed by Halliburton Energy Services. 
     In each completion equipment set  20 , a pressure sensor  36  is included for sensing pressure internal and/or external to the completion string  12 . The pressure sensor  36  could be provided as part of the hydraulic control device  34  (such as, part of the SCRAMS™ device), or a separate pressure sensor may be used. If a separate pressure sensor  36  is used, a suitable sensor is the ROC™ pressure sensor marketed by Halliburton Energy Services, Inc. 
     After the gravel packing operation is completed, a gravel packing work string and service tool (not shown) used to convey the completion string  12  into the well is retrieved, and a production string  38  is lowered into the wellbore  14  and stabbed into the completion string  12 . The production string  38  in this example includes seals  40  for sealingly engaging a seal bore  42  in an uppermost one of the packers  26 , an expansion joint  44  for convenient spacing out to a tubing hanger in a wellhead (not shown), and a packer  46 . 
     The expansion joint  44  may be similar to a Long Space Out Travel Joint, or LSOTJ™, marketed by Halliburton Energy Services, Inc., except that provision is made for extending the lines  48  across the expansion joint. Preferably, the seals  40  are stabbed into the seal bore  42 , and then the expansion joint  44  is actuated to allow it to compress, so that proper spacing out is achieved for landing a wellhead above. The packer  46  is then set, for example, by applying pressure to one of the hydraulic lines  48 . 
     When the production string  38  is landed in the completion string  12 , a wet connection is made between lines  48  carried on the production string and lines  50  carried on the completion string. Preferably, the lines  48 ,  50  each include one or more electrical, hydraulic and optical lines (e.g., at least one optical waveguide, such as, an optical fiber, optical ribbon, etc.). An example of such a wet connection is depicted in  FIG. 7 , and is described more fully below. 
     In the  FIG. 1  example, the lines  48 ,  50  are depicted as being external to the production string  38  and completion string  12 , respectively, but in other examples all or part of the lines could be positioned internal to the production and/or completion string, or in a wall of the production and/or completion string. The scope of this disclosure is not limited to any particular locations of the lines  48 ,  50 . 
     Preferably, the optical waveguide(s) is/are external to the completion string  12  (for example, between the well screens  24  and the wellbore  14 ), so that properties of fluid  52  which flows between the zones  28  and the interior of the completion string  12  can be readily detected by the optical waveguide(s). In other examples, the optical waveguide could be positioned in a wall of the casing  16 , external to the casing, in the cement  18 , etc. 
     Preferably, the optical waveguide is capable of sensing temperature and/or pressure of the fluid  52 . For example, the optical waveguide may be part of a distributed temperature sensing (DTS) system which detects Rayleigh backscattering in the optical waveguide as an indication of temperature along the waveguide. For pressure sensing, the optical waveguide could be equipped with fiber Bragg gratings and/or Brillouin backscattering in the optical waveguide could be detected as an indication of strain (resulting from pressure) along the optical waveguide. However, the scope of this disclosure is not limited to any particular technique for sensing any particular property of the fluid  52 . 
     The fluid  52  is depicted in  FIG. 1  as flowing from the zones  28  into the completion string  12 , as in a production operation. However, the principles of this disclosure are also applicable to situations (such as, acidizing, fracturing, other stimulation operations, conformance or other injection operations, etc.), in which the fluid  52  is injected from the completion string  12  into one or more of the zones  28 . 
     In one method, all of the flow control devices  32  can be closed, to thereby prevent flow of the fluid  52  through all of the screens  24 , and then one of the flow control devices can be opened to allow the fluid to flow through a corresponding one of the screens. In this manner, the properties of the fluid  52  which flows between the respective zone  28  and through the respective well screen  24  can be individually detected by the optical waveguide. The pressure sensors  36  can meanwhile detect internal and/or external pressures longitudinally distributed along the completion string  12 , and this will provide an operator with significant information on how and where the fluid  52  flows between the zones  28  and the interior of the completion string. 
     This process can be repeated for each of the zones  28  and/or each of the sets  20  of completion equipment, so that the fluid  52  characteristics and flow paths can be accurately modeled along the completion string  12 . Water or gas encroachment, water or steam flood fronts, etc., in individual zones  28  can also be detected using this process. 
     Referring additionally now to  FIGS. 2A-C , an example of one longitudinal section of the completion string  12  is representatively illustrated. The illustrated section depicts how flow through the well screens  24  can be controlled effectively using the flow control devices  32 . The section shown in  FIGS. 2A-C  may be used in the system  10  and completion string  12  of  FIG. 1 , or it may be used in other systems and/or completion strings. 
     In the  FIGS. 2A-C  example, three of the flow control devices  32  are used to variably restrict flow through six of the well screens  24 . This demonstrates that any number of flow control devices  32  and any number of well screens  24  may be used to control flow of the fluid  52  between a corresponding one of the zones  28  and the completion string  12 . The scope of this disclosure is not limited to any particular number or combination of the various components of the completion string  12 . 
     Another flow control device  54  (such as, a mechanically actuated sliding sleeve-type valve, etc.) may be used to selectively permit and prevent substantially unrestricted flow through the well screens  24 . For example, during gravel packing operations, it may be desired to allow unrestricted flow through the well screens  24 , for circulation of slurry fluid back to the earth&#39;s surface. In fracturing or other stimulation operations, the flow control device  54  can be closed to thereby prevent flow through the screens  24 , so that sufficient pressure can be applied external to the screens to force fluid outward into the corresponding zone  28 . 
     An upper one of the hydraulic control devices  34  is used to control operation of an upper one of the flow control devices  32  ( FIG. 2A ), and to control an intermediate one of the flow control devices ( FIG. 2B ). A lower one of the hydraulic control devices  34  is used to control actuation of a lower one of the flow control devices  32  ( FIG. 2C ). 
     If the SCRAMS™ device mentioned above is used for the hydraulic control devices  34 , signals transmitted via the electrical lines  50  are used to control application of hydraulic pressure from the hydraulic lines to a selected one of the flow control devices  32 . Thus, the flow control devices  32  can be individually actuated using the hydraulic control devices  34 . 
     In  FIG. 2A , it may be seen that an inner tubular  60  is secured to an outer tubular  94  (for example, by means of threads, etc.), so that the inner tubular  60  can be used to support a weight of a remainder of the completion string  12  below. 
     Referring additionally now to  FIG. 3 , an example of how the flow control device  32  can be used to control flow of the fluid  52  through the well screen  24  is representatively illustrated. In this view, it may be seen that the fluid  52  enters the well screen  24  and flows into an annular area  56  formed radially between a perforated base pipe  58  of the well screen and an inner tubular  60 . The fluid  52  flows through the annular area  56  to the flow control device  32 , which is contained within an outer tubular shroud  62 . 
     The flow control device  32  variably restricts the flow of the fluid  52  from the annular area  56  to a flow passage  64  extending longitudinally through the completion string  12 . Such variable restriction may be used to balance production from the multiple zones  28 , to prevent water or gas coning, etc. Of course, if the fluid  52  is injected into the zones  28 , the variable restriction may be used to control a shape or extent of a water or steam flood front in the various zones, etc. 
     Referring additionally now to  FIG. 4 , a manner in which the lines  50  may be routed through the completion string  12  is representatively illustrated. In this view, the shroud  62  is removed, so that the lines  50  extending from one of the flow control devices  32  (such as, the intermediate flow control device depicted in  FIG. 2B ) to a well screen  24  below the flow control device may be seen. 
     The lines  50  extend from a connector  66  on the flow control device  32  to an end connection  68  of the well screen  24 , wherein the lines are routed to another connector  70  for extending the lines further down the completion string  12 . The end connection  68  may be provided with flow passages (not shown) to allow the fluid  52  to flow longitudinally through the end connection from the well screen  24  to the flow control device  32  via the annular area  56 . Casting the end connection  68  can allow for forming complex flow passage and conduit shapes in the end connection, but other means of fabricating the end connection may be used, if desired. 
     Referring additionally now to  FIG. 5 , another example of the completion system  10  and completion string  12  is representatively illustrated. In this example, the set  20  of completion equipment includes only one each of the well screen  24 , flow control device  32 , hydraulic control device  34  and flow control device  54 . However, as mentioned above, any number or combination of components may be used, in keeping with the scope of this disclosure. 
     One difference in the  FIG. 5  example is that the flow control device  54  and at least a portion of the flow control device  32  are positioned within the well screen  24 . This can provide a more longitudinally compact configuration, and eliminate use of the shroud  62 . Thus, it will be appreciated that the scope of this disclosure is not limited to any particular configuration or arrangement of the components of the completion string  12 . 
     In addition, it can be seen in  FIG. 5  that the hydraulic control device  34  can include the pressure sensor  36 , which can be ported to the interior flow passage  64  and/or to the annulus  30  external to the completion string  12 . Multiple pressure sensors  36  may be provided in the hydraulic control device  34  to separately sense pressures internal to, or external to, the completion string  12 . 
     Referring additionally now to  FIG. 6 , another example of how the flow control device  32  may be connected to the hydraulic control device  34  is representatively illustrated. In this example, the hydraulic control device  34  includes electronics  72  (such as, one or more processors, memory, batteries, etc.) responsive to signals transmitted from a remote location (for example, a control station at the earth&#39;s surface, a sea floor installation, a floating rig, etc.) via the lines  50  to direct hydraulic pressure (via a hydraulic manifold, not shown) to an actuator  74  of the flow control device  32 . 
     The  FIG. 6  flow control device  32  includes a sleeve  76  which is displaced by the actuator  74  relative to an opening  78  in an outer housing  80 , in order to variably restrict flow through the opening. Preferably, the flow control device  32  also includes a position indicator  82 , so that the electronics  72  can verify whether the sleeve  76  is properly positioned to obtain a desired flow restriction. The pressure sensor(s)  36  may be used to verify that a desired pressure differential is achieved across the flow control device  32 . 
     Referring additionally now to  FIG. 7 , a manner in which a wet connection  84  can be made between the lines  48  on the production string  38  and the lines  50  on the completion string  12  is representatively illustrated. In this example, the wet connection  84  is made above the uppermost packer  26 , but in other examples the wet connection could be made within the packer, below the packer, or in another location. 
     As depicted in  FIG. 7 , a wet connector  86  on the production string  38  is axially engaged with a wet connector  88  on the completion string  12  when the seals  40  are stabbed into the seal bore  42 . Although only one set is visible in  FIG. 7 , the wet connection  84  preferably includes connectors  86 ,  88  for each of electrical, hydraulic and optical connections between the lines  48 ,  50 . 
     However, it is not necessary for all of the electrical, hydraulic and optical wet connections to be made by axial engagement of connectors  86 ,  88 . For example, radially oriented hydraulic connections can be made by use of longitudinally spaced apart seals and ports on the production string  38  and completion string  12 . As another example, an electrical wet connection could be made with an inductive coupling. Thus, the scope of this disclosure is not limited to use of any particular type of wet connectors. 
     Referring additionally now to  FIG. 8 , a manner in which the lines  48  may be extended through the expansion joint  44  in the system  10  is representatively illustrated. In this view, it may be seen that the lines  48  (preferably including electrical, hydraulic and optical lines) are coiled between an inner mandrel  90  and an outer housing  92  of the expansion joint  44 . 
     However, note that use of the expansion joint  44  is not necessary in the system  10 . For example, a spacing between the uppermost packer  26  and a tubing hanger seat in the wellhead (not shown) could be accurately measured, and the production string  38  could be configured correspondingly, in which case the packer  46  may not be used on the production string. 
     Although the flow control device  32  in the above examples is described as being a remotely hydraulically actuated variable choke, any type of flow control device which provides a variable resistance to flow may be used, in keeping with the scope of this disclosure. For example, a remotely actuated inflow control device may be used. An inflow control device may be actuated using the hydraulic control device  34  described above, or relatively straightforward hydraulic control lines may be used to actuate an inflow control device. 
     Alternatively, an autonomous inflow control device (one which varies a resistance to flow without commands or actuation signals transmitted from a remote location), such as those described in US Publication Nos. 2011/0042091, 2011/0297385, 2012/0048563 and others, may be used. 
     Use of an inflow control device (autonomous or remotely actuated) may be preferable for injection operations, for example, if precise regulation of flow resistance is not required. However, it should be appreciated that the scope of this disclosure is not limited to use of any particular type of flow control device, or use of a particular type of flow control device in a particular type of operation. 
     Alternatively, a remotely operable sliding sleeve valve which opens on command from the surface could be utilized. An opening signal could be conveyed by electric control line, or the signal could be sent from the surface down the tubing, e.g., via HALSONICS™ pressure pulse telemetry, an ATS™ acoustic telemetry system, DYNALINK™ mud pulse telemetry system, an electromagnetic telemetry system, etc. The sliding sleeve valve could have a battery, a sensor, a computer (or at least a processor and memory), and an actuation system to open on command. 
     Instead of, or in addition to, the pressure sensors  36 , separate pressure and/or temperature sensors may be conveyed into the completion string  12  during the method described above, in which characteristics and flow paths of the fluid  52  flowing between the completion string and the individual zones  28  are determined. For example, a wireline or coiled tubing conveyed perforated dip tube could be conveyed into the completion string during or prior to performance of the method. 
     It may now be fully appreciated that the above disclosure provides significant advancements to the art of constructing and operating well completion systems. In examples described above, enhanced well diagnostics are made possible by use of a selectively variable flow control device  32  integrated with an optical sensor (e.g., an optical waveguide as part of the lines  50 ) external to the completion string  12 , and pressure sensors  36  ported to an interior and/or exterior of the completion string. 
     A system  10  for use with a subterranean well having multiple earth formation zones  28  is provided to the art by the above disclosure. In one example, the system  10  can include: multiple well screens  24  which filter fluid  52  flowing between a completion string  12  in the well and respective ones of the multiple zones  28 ; at least one optical waveguide  50  which senses at least one property of the fluid  52  as it flows between the completion string  12  and at least one of the zones  28 ; multiple flow control devices  32  which variably restrict flow of the fluid  52  through respective ones of the multiple well screens  24 ; and multiple pressure sensors  36  which sense pressure of the fluid  52  which flows through respective ones of the multiple well screens  24 . 
     The multiple well screens  24 , the optical waveguide  50 , the multiple flow control devices  32 , and the multiple pressure sensors  36  can be installed in the well in a single trip into the well. 
     The system  10  can also include multiple hydraulic control devices  34  which control application of hydraulic actuation pressure to respective ones of the multiple flow control devices  32 . 
     A single one of the hydraulic control devices  34  may control application of hydraulic actuation pressure to multiple ones of the flow control devices  32 . 
     The pressure sensors  36  may sense pressure of the fluid  52  external and/or internal to the completion string  12 . 
     The flow control devices  32  may comprise remotely hydraulically actuated variable chokes. The flow control devices  32  may comprise autonomous variable flow restrictors. 
     The flow control devices  32 , in some examples, receive the fluid  52  from the respective ones of the multiple well screens  24 . 
     The system  10  may include a combined hydraulic, electrical and optical wet connection  84 . 
     The system  10  may include an expansion joint  44  with hydraulic, electrical and optical lines  48  traversing the expansion joint  44 . 
     The optical waveguide  50  can be positioned external to the well screens  24 . The optical waveguide  50  can be positioned between the well screens  24  and the zones  28 . 
     Also described above is a completion string  12  for use in a subterranean well. In one example, the completion string  12  can include at least one well screen  24 ; at least one first flow control device  54 ; and at least one second flow control device  32 , the second flow control device  32  being remotely operable. The first flow control device  54  selectively prevents and permits substantially unrestricted flow through the well screen  24 . The second flow control device  32  variably restricts flow through the well screen  24 . 
     The completion string  12  can include a hydraulic control device  34  which controls application of hydraulic actuation pressure to the second flow control device  32 . 
     The second flow control device  32  may comprise multiple second flow control devices  32 , and the hydraulic control device  34  may control application of hydraulic actuation pressure to the multiple second flow control devices  32 . 
     The completion string  12  can include at least one optical waveguide  50  which is operative to sense at least one property of a fluid  52  which flows through the well screen  24 . 
     A method of operating a completion string  12  in a subterranean well is also described above. In one example, the method can comprise: closing all of multiple flow control devices  32  connected in the completion string  12 , the completion string  12  including multiple well screens  24  which filter fluid  52  flowing between the completion string  12  and respective ones of multiple earth formation zones  28 , at least one optical waveguide  50  which senses at least one property of the fluid  52  as it flows between the completion string  12  and at least one of the zones  28 , the multiple flow control devices  32  which variably restrict flow of the fluid  52  through respective ones of the multiple well screens  24 , and multiple pressure sensors  36  which sense pressure of the fluid  52  which flows through respective ones of the multiple well screens  24 ; at least partially opening a first selected one of the flow control devices  32 ; and measuring a first change in the property sensed by the optical waveguide  50  and a first change in the pressure of the fluid  52  as a result of the opening of the first selected one of the flow control devices  32 . 
     The method can also include: closing all of the multiple flow control devices  32  after the step of at least partially opening the first selected one of the flow control devices  32 ; at least partially opening a second selected one of the flow control devices  32 ; and measuring a second change in the property sensed by the optical waveguide  50  and a second change in the pressure of the fluid  52  as a result of the opening of the second selected one of the flow control devices  32 . 
     The method can include installing the multiple well screens  24 , the optical waveguide  50 , the multiple flow control devices  32 , and the multiple pressure sensors  36  in the well in a single trip into the well. 
     The method can include closing all of the flow control devices  32 , thereby preventing inadvertent flow of the fluid  52  into the completion string  12 . This step can be useful in a well control situation. 
     The method can include closing all of the flow control devices  32 , thereby preventing inadvertent flow of the fluid  52  out of the completion string  12 . This step can be useful in preventing loss of the fluid  52  to the surrounding zones  28 . 
     Although various examples have been described above, with each example having certain features, it should be understood that it is not necessary for a particular feature of one example to be used exclusively with that example. Instead, any of the features described above and/or depicted in the drawings can be combined with any of the examples, in addition to or in substitution for any of the other features of those examples. One example&#39;s features are not mutually exclusive to another example&#39;s features. Instead, the scope of this disclosure encompasses any combination of any of the features. 
     Although each example described above includes a certain combination of features, it should be understood that it is not necessary for all features of an example to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used. 
     It should be understood that the various embodiments described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of this disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments. 
     In the above description of the representative examples, directional terms (such as “above,” “below,” “upper,” “lower,” etc.) are used for convenience in referring to the accompanying drawings. However, it should be clearly understood that the scope of this disclosure is not limited to any particular directions described herein. 
     The terms “including,” “includes,” “comprising,” “comprises,” and similar terms are used in a non-limiting sense in this specification. For example, if a system, method, apparatus, device, etc., is described as “including” a certain feature or element, the system, method, apparatus, device, etc., can include that feature or element, and can also include other features or elements. Similarly, the term “comprises” is considered to mean “comprises, but is not limited to.” 
     Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the disclosure, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of this disclosure. For example, structures disclosed as being separately formed can, in other examples, be integrally formed and vice versa. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the invention being limited solely by the appended claims and their equivalents.