Patent Publication Number: US-11639637-B2

Title: System and method for centralizing a tool in a wellbore

Description:
BACKGROUND 
     Downhole tools are conveyed into wellbores to perform various tasks. In some instances, gravity may cause the downhole tool to become decentralized in deviated and/or horizontal wells. Portions of certain downhole tools, such as perforating guns, may be less effective in a decentralized position. For example, perforating charges of perforating guns lose energy and penetrate less effectively when the perforating charges are further from a surface of a tubular in the wellbore, which occurs in some directions when perforating guns are not centralized. However, including a system that centralizes a downhole tool may increase the diameter of the downhole tool, thereby restricting access of the downhole tool in certain sections of the wellbore may include a reduced diameter. Increasing the diameter of a downhole tool may cause the downhole tool to be unable to access and/or pass the sections of the wellbore that have a reduced diameter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the system and method for centralizing a tool in a wellbore are described with reference to the following figures. The same numbers are used throughout the figures to reference like features and components. The features depicted in the figures are not necessarily shown to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form, and some details of elements may not be shown in the interest of clarity and conciseness. 
         FIG.  1    illustrates a wellbore system that includes downhole tools positioned within a wellbore that extends into a formation, according to one or more embodiments; 
         FIG.  2 A  illustrates a downhole tool that includes a centralizing system in a retracted position, according to one or more embodiments; 
         FIG.  2 B  illustrates the downhole tool that includes the centralizing system of  FIG.  2 A  with an ignited power charge, according to one or more embodiments; 
         FIG.  3    illustrates a downhole tool that includes a centralizing system in an extended position, according to one or more embodiments; 
         FIG.  4    illustrates a downhole tool that includes a centralizing system as a bladder extending over a portion of the downhole tool, according to one or more embodiments; 
         FIG.  5    illustrates a downhole tool that includes a centralizing system as a bladder extending over a portion of the downhole tool, according to one or more embodiments; 
         FIG.  6 A  illustrates a downhole tool that includes a centralizing system as an arm extendable into engagement with a surface of a wellbore, according to one or more embodiments; 
         FIG.  6 B  illustrates a downhole tool that includes multiple centralizing systems illustrated in  FIG.  6 A , according to one or more embodiments; 
         FIG.  7    is a flow chart for centralizing a downhole tool in a wellbore, according to one or more embodiments; and 
         FIGS.  8 A and  8 B  illustrate results of a perforating gun in a centralized position versus a decentralized position. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure provides systems and methods for centralizing a downhole tool in a wellbore. 
       FIG.  1    illustrates a wellbore system  10  that includes a rig  12  that is positioned over a wellbore  14  that extends into a formation  16 . The wellbore  14  is an opening in the formation  16  and may include a tubular such as a casing or a lining or the wellbore  14  may be an open hole. The wellbore  14  is used to extract fluids or store fluids, such as hydrocarbons or water. Further, while the wellbore  14  is shown as extending vertically and horizontally into the formation  16 , the wellbore  14 , or portions of the wellbore  14 , may extend at any angle between vertical and horizontal. In some embodiments, the wellbore  14  may extend only vertically into the formation  16 . 
     The rig  12  is utilized to aid in operations that include the use of the wellbore  14 . For example, the rig  12  includes a drilling rig, a completion rig, a workover rig, or a servicing rig. The rig  12  supports the wireline  18 , which conveys one or more downhole tools  20  into the wellbore  14 . The position of the downhole tools  20  in the wellbore  14  may be monitored, such as by sensors positioned on the downhole tools  20  or by measuring a length of wireline  18  conveyed into the wellbore  14 . In one or more embodiments, the rig  12  supports a slickline unit, a tubular string, a hoisting apparatus, a servicing vehicle, or a coiled tubing unit. Further, the wellbore system  10  may be positioned at an offshore location. For example, the rig  12  may be supported by piers extending into the seabed or by a floating structure. 
     The wireline  18  supports one or multiple downhole tools  20 . One or more of the downhole tools  20  includes a centralizing system  22  that centralizes one or more downhole tools  20  within the wellbore  14  or within a tubular  23  within the wellbore, e.g., a casing or liner. For example, the centralizing system  22  may be included on a portion of one of the downhole tools  20 , the centralizing system  22  may surround one of the downhole tools  20 , or the centralizing system  22  may be positioned proximate to one of the downhole tools  20 . As described in detail below, the centralizing system  22  includes an extendable member  52  that engages a tubular wall or a casing wall  24  to bias the associated downhole tool  20  into a centralized position within the tubular or wellbore. Further, in one example, the downhole tools  20  include perforating tools, which each include one or more explosive charges to perforate the tubular wall  23 . Perforation of the tubular  23  enables extraction of fluids from the formation  16 . 
     Further, the centralizing system  22  includes an extendable member that extends into engagement with the tubular  23  to centralize the downhole tool  20 . As discussed in greater detail below, the extendable member may include any structure that extends in response to an increase in pressure. For example, the extendable member may be inflatable or a solid member that is pushed outwardly. For example, the extendable member may be positioned within the downhole tool  20  and extend from the downhole tool  20 . The extendable member may extend over the downhole tool  20  to surround at least a portion of the downhole tool  20  and inflate into engagement with the tubular  23  to centralize the downhole tool  20 . Further, the extendable member may be an arm that rotates about a pivot into engagement with the tubular  23  to centralize the downhole tool  20 . 
     In addition, the extendable member may be actuated by a power charge. For example, a power charge may ignite, releasing gas and thereby increasing pressure. This gas and increase in pressure can be used to directly inflate the extendable member and/or the gas and increase in pressure can be used to operate a mechanism that extends the extendable member, as described in further detail below. The gas produced by the power charge may be contained in a chamber that is pressure isolated from the rest of the downhole tool such that other components of the downhole tool are not exposed to the increase in pressure. Further, the power charge may be a part of a ballistic sequence that includes perforating charges. For example, a detonator may initiate a ballistic sequence that initiates the power charge and perforating charges. 
       FIG.  2 A  illustrates the downhole tool  20  with the centralizing system  22  in a retracted position and located within a casing  23  with the casing wall  24 . As the downhole tool  20  travels through the wellbore  14 , the downhole tool  20  may become positioned closer to one portion of the casing wall  24  than another portion of the casing wall  24 , which may be considered a decentralized position. For example, the downhole tool  20  is illustrated in contact with an interior diameter  40  of the casing wall  24 , thereby leaving an uneven gap  42  on one side of the downhole tool  20 . The downhole tool  20  may become decentralized by gravity when in an angled or horizontal portion of the wellbore  14  or there may be obstructions (e.g., uneven distribution of fluids) that bias the downhole tool  20  toward the casing wall  24 . 
     The efficiency of certain downhole tools  20  may be enhanced by centralizing the downhole tool  20 . For example, as illustrated in  FIG.  2 A , the downhole tool  20  may be a perforating gun that includes a tool housing  44 , a charge loading tube  46 , and explosive charges  48 . Further, an interior  54  of the downhole tool  20  is enclosed by the tool housing  44 . The tool housing  44  has an outer diameter that determines the minimum diameter casing through which the downhole tool  20  may pass. As illustrated, the extendable member  52  comprises an inflatable member that, when in the retracted position, does not extend further than the outer diameter of the tool housing  44 , which, in turn, does not affect the minimum diameter through which the downhole tool  20  may pass. 
     As the downhole tool  20  reaches a desired location, the explosive charges  48  may be detonated to perforate the casing wall  24  to enable and/or enhance the extraction of fluids from the formation  16 . A power charge  50  is included to initiate the detonation of the explosive charge  48 . The power charge  50  may be actuated hydraulically, pneumatically, or electrically. Further, the power charge  50  produces a fluid upon actuation via either ignition or a chemical reaction. The power charge  50  may be initiated separately from a charge that detonates the explosive charge  48 . For example, the power charge  50  may be attached to a separate igniter, which may be controlled by a separate switch (e.g., hydraulic, pneumatic, or electric). In this configuration, the initiation of the power charge  50  is not linked to the initiation of the explosive charge  48 , enabling the power charge  50  to be further isolated from the explosive charge  48 . 
     In one or more embodiments, initiation of the power charge  50  is linked to the initiation of the explosive charge  48 . For example, the power charge  50  and the explosive charge  48  may be linked on a timed chain and/or ignition circuit such that the power charge  50  is initiated before the explosive charge  48  is initiated. In this configuration, the initiation of the power charge  50  and the explosive charge  48  are linked which may improve reliability of the timing of the initiation. 
     Further, the power charge  50  may be utilized to activate the centralizing system  22  to extend an extendable member  52  from the retracted position to an extended position show in  FIG.  2 B . For example, actuation of the power charge  50  actuates the extendable member  52  prior to detonating the explosive charges  48  to centralize the downhole tool  20  prior to initiation of the explosive charges  48 . Centralization of the downhole tool  20  prior to initiation of the explosive charges  48  provides a more uniform perforation of the casing wall  24 . 
     Turning to  FIG.  2 B , the power charge  50  has ignited, thereby generating a fluid that increases the pressure within the interior  54  of the downhole tool  20  to extend the extendable member  52  into the extended position. An extendable member  52  is included on both longitudinal sides of the downhole tool  20  to balance the centralization of the downhole tool  20 . In some embodiments, more extendable members  52  may be included on one longitudinal side of the downhole tool  20  to accommodate, for example, for uneven weight distribution. Further, extendable members  52  may also only be included on one side of the downhole tool  20  to produce a desired positioning. 
     After the extendable members  52  are in the extended position, the downhole tool  20  is pushed away from the casing wall  24  and into a centralized position within the casing. Once the downhole tool  20  is in the centralized position, the explosive charges  48  are detonated to perforate the casing wall  24 . 
     Detonation of the explosive charges  48  also introduces holes into the tool housing  44  that equalize the pressure between the interior  54  and the wellbore  14 . Equalization of the pressure may cause the extendable member  52  to retract from the extended position of  FIG.  2 B  to the retracted position of  FIG.  2 A , thereby releasing the downhole tool  20  from the casing wall  24  and allowing the downhole tool  20  to be moved within or removed from the wellbore  14 . 
       FIG.  3    illustrates the downhole tool  120  that includes the centralizing system  122  in the extended position. The power charge  150  is included in a chamber  160  that is fluidly separate from the interior  154 . For example, the fluid produced by the power charge  150  will not enter the interior  154  to increase the pressure within the interior  154 . By not increasing the pressure within the interior  154 , the explosive charges  148  are not introduced to an elevated pressure prior to their detonation which prevents movement of the explosive charges  148  prior to detonation of the explosive charges  148 . 
     Further, a power charge  150  is included for each of the extendable members  152  because one power charge  150  is not fluidly coupled to multiple extendable members  152  via the interior  154 . Passageways may alternatively be included to fluidly couple multiple extendable members  152  to one power charge  150 . The downhole tool  120  may also include additional structure to reduce the pressure that extends the extendable members  152  to enable the extendable members  152  to retract after the explosive charges  148  are initiated, thereby enabling the downhole tool  120  to be moved within or removed from the wellbore  14 . For example, a rupture disk may be included that, when ruptured, enables fluid to escape from the chamber  160 , thereby lowering the pressure acting on the extendable member  152 . The rupture disk may be included in proximity to a detonating cord or a booster (e.g., an explosive capsule) that ruptures the rupture disk in response to the explosive charges  148  detonating. Further, a valve may be included that releases fluid from the chamber  160  in response to a threshold pressure. For example, the threshold pressure, measured as a differential with respect to pressure within the wellbore  14 , may be 250 pounds per square inch (psi), 500 psi, 750 psi, 1000 psi, 2500 psi, 5000 psi, or more. Further, the downhole tool  120  may include a valve to release fluids when the pressure within the chamber  160  is higher than the pressure in the wellbore  14  or the interior  154 . Release of fluid from the chamber  160  causes the pressure between the chamber  160  and the interior  154  or wellbore  14  to equalize, which, in turn, causes the extendable members  152  to retract and disengage from the casing wall  24 . 
     Further, the extendable members  152  may retract in response to certain directional forces. For example, if the downhole tool  120  is pulled in a longitudinal direction, a shear force may be introduced on the extendable member  152  that causes the extendable member  152  to either become unsealed or tear open, thereby equalizing pressure between the chamber  160  and the wellbore  14 . Further, the amount of pressure created by the power charge  150  may cause the extendable member  152  to continue extending past the extended position until the extendable member  152  fails, thereby equalizing the pressure between the chamber  160  and the wellbore  14 . Reduction of the pressure within the chamber  160  enables the extendable member  152  to retract and disengage from the casing wall  24 , which, in turn, enable the downhole tool  120  to be moved within or removed from the wellbore  14 . 
       FIG.  4    illustrates the extendable member  252  as a bladder that extends over a portion of the downhole tool  220 . The extendable member  252  is fluidly coupled to the interior  254  such that when the power charge  250  releases a fluid, the fluid fills both the interior  254  and the extendable member  252 , thereby extending the extendable member  252  into the illustrated extended position. Thus, when the extendable member  252  is in the extended position, the explosive charges  48  do not penetrate fluids contained within the wellbore  14 . Rather, the explosive charges penetrate the tool housing  244 , the fluid within the tool housing  244 , the extendable member  252 , and the casing wall  24 . Avoiding penetration of fluids within the wellbore  14  may increase the depth and diameter of the perforations in the formation. Further, after the explosive charges  248  penetrate the extendable member  252 , the pressure within the extendable member  252  equalizes with the pressure within the wellbore  14 , thereby causing the extendable member  252  to retract and enable the downhole tool  220  to be moved within or removed from the wellbore  14 . 
       FIG.  5    illustrates the extendable member  352  as a bladder that extends over a portion of the downhole tool  320  and is fluidly separate from the interior  354 . The power charge  350  is included in a chamber  380  that is fluidly separate from the interior  354 . For example, the fluid produced by the power charge  350  will not enter the interior  354  to increase the pressure within the interior  354 . By not increasing the pressure within the interior  354 , the explosive charges  348  are not introduced to an elevated pressure prior to their detonation which may prevent movement or a change in orientation of the explosive charges  348  prior to initiation of the explosive charges  348 . When the extendable member  352  is in the extended position, the explosive charges  348  do not penetrate fluids contained within the wellbore  14 . Rather, the explosive charges penetrate the tool housing  344 , the fluid within the extendable member  352 , the extendable member  352 , and the casing wall  24 . Avoiding penetration of fluids within the wellbore  14  may increase the depth and diameter of the perforations in the formation. Further, after the explosive charges  348  penetrate the extendable member  352 , the pressure within the extendable member  352  equalizes with the pressure within the wellbore  14 , thereby causing the extendable member  352  to retract, thereby enabling the downhole tool  320  to be moved within or removed from the wellbore  14 . 
       FIG.  6 A  illustrates the extendable member  421  as an arm  400  that rotates about a pin  402  to extend into contact with the casing wall  24 , thereby biasing the downhole tool  419  into a centralized position. The arm  400  is rotated by an axial displacement system  410  that includes a piston system  412  and a bias member  414  (e.g., a spring, a compressible fluid, etc.). 
     The piston system  412  includes a power charge  416  (e.g., an explosive or combustible member), a piston  418 , and a cylinder  420  with a first chamber  422  and a second chamber  424 . Further, the piston  418  is coupled to an arm retainer  426  that retains an end  428  of the arm  400  in a slot  430  of the arm retainer  426 . When the power charge  416  ignites, the power charge  416  creates an increase in pressure within the first chamber  422 , thereby biasing the piston  418  away from the power charge  416 . As the piston  418  moves away from the power charge  416 , the arm retainer  426  also moves away from the power charge  416 . Further, the movement of the arm retainer  426  causes the arm  400  to rotate about the pin  402  and extend into contact with the casing wall  24 . As the arm  400  contact the casing wall  24 , the arm  400  biases the downhole tool  419  into a centralized position. 
     The downhole tool  419  also includes structure that enables the arm  400  to automatically retract after extension, thereby enabling the downhole tool  419  to be moved within or removed from the wellbore  14 . The piston  418  includes a slot  432  that fluidly couples the first chamber  422  and the second chamber  424  which allows the pressures within the first chamber  422  and the second chamber  424  to equalize over time. As the pressures within the first chamber  422  and the second chamber  424  equalize, the biasing force provided by the bias member  414  overcomes the pressure differential between the first chamber  422  and second chamber  424  to push the arm retainer  426  and the piston  418  back toward the power charge  416 , thereby retracting the arm  400 . 
     The piston system  412  may include additional slots to fluidly couple the first chamber  422  and/or the second chamber  424  to areas surrounding the cylinder  420 . Further, the piston system  412  includes a first seal  434  that blocks fluid from flowing between an edge of the piston  418  and a wall of the cylinder  420 . The piston system  412  also includes a second seal  436  that blocks fluid from flowing between an edge of the piston  418  and out of the cylinder  420 . The first seal  434  and the second seal  436  provide a more consistent motion of the piston  418  and increase the control of fluid flowing between different areas. 
     The downhole tool  419  may also include multiple arms  400  positioned at different axial and circumferential positions, as illustrated in  FIG.  6 B . The arms  400  are illustrated as being in two distinct axial positions, each axial position having two arms  400  equally circumferentially distributed. Further, the arms  400  are positioned upstream of a perforating gun  460 . In some embodiments, the arms  400  may be positioned in more than two axial positions. Further, each axial position may include more than two arms  400 , and the arms  400  may not be equally circumferentially distributed. Having arms  400  in at least two distinct axial positions increases the centralization of the perforating gun  460 . 
       FIG.  7    illustrates a flow chart  500  for centralizing a downhole tool in a wellbore. A downhole tool having an extendable member is conveyed downhole into a wellbore in step  502 . The position of the downhole tool is monitored as the downhole tool travels through the wellbore. The functionality of the downhole tool may be desired at a particular position downhole. Thus, the position of the downhole tool is determined in step  504 . 
     Once the downhole tool is in the desired position, centralization of the downhole tool may begin. As described above, the downhole tool may become decentralized as it travels through the wellbore. For deviated and/or horizontal wells, gravity may bias the downhole tool into a decentralized position. In some instances, there may be obstructions that bias the downhole tool into a decentralized position. To begin the centralization of the downhole tool, a power charge is actuated in step  506  to provide the energy to centralize the downhole tool. 
     The actuation of the power charge in step  506  causes an extendable member to extend in step  508 . As the extendable member extends, the extendable member engages a surface of the casing, which biases the downhole tool away from the surface of the casing and into a centralized position. 
     In embodiments in which the downhole tool is a perforating gun, perforating charges are actuated to perforate the wellbore in step  510  after the downhole tool is in the centralized position. Actuation of the perforating charges when the downhole tool is in the centralized position provides a more even perforation of the wellbore. As described in more detail below, a more even perforation of the wellbore enhances the extraction of formation fluids. 
     After the extendable member has centralized the downhole tool and/or the perforating charges have been actuated, the extendable members are retracted in step  512  to disengage the extendable member from the surface of the wellbore, thereby enabling the downhole tool to be moved within or removed from the wellbore. As described above, the extendable member may also disengage from the surface of the wellbore via a shear force. For example, the extendable member may not retract, and a shear force may be applied to the extendable member (e.g., via pulling the downhole tool in an uphole direction). In response to the shear force, the extendable member may shear and retract from the surface of the wellbore. After the extendable member retracts, the downhole tool is free to be moved to another position within the wellbore or pulled out of the wellbore. Those skilled in the art will see that the described method and apparatus is not limited to positioning perforating tools but may be used to centralize other downhole equipment. It may also be appreciated by those skilled in the art that adaptations of the methods and apparatus described here may be used to position tools in a wellbore in a non-centralized location. 
       FIG.  8 A  illustrates a sample result of a perforating gun  600  operating from a centralized position, and  FIG.  8 B  illustrates a sample result of the perforating gun  600  operating from a decentralized position. In the illustrated results, the perforating gun  600  includes six perforating charges equally circumferentially positioned, and each producing a penetration visualization  602 . The perforating gun  600  operating from the centralized position in  FIG.  8 A  increases the total penetration as well as the flow area of the hole produced by each of the perforation charges, thereby increasing the production of formation fluid. 
     Further examples may include: 
     Example 1 is a centralizing perforating gun for perforating a tubular in a wellbore comprising a gun housing, perforating charges positioned within the gun housing and detonatable to perforate the tubular, and a centralizing system. The centralizing system includes an extendable member configured to move between a retracted position and an extended position. The extendable member is configured to engage a surface of the tubular in the extended position, thereby biasing the centralizing perforating gun away from the surface of the tubular. 
     In Example 2, the subject matter of Example 1 can further include a power charge ignitable to extend the extendable member from the retracted position to the extended position. 
     In Example 3, the subject matter of Examples 1-2 can further include wherein the power charge is configured to extend the extendable member prior to detonation of the perforating charges. 
     In Example 4, the subject matter of Examples 1-3 can further include a detonator detonatable separately from the power charge to initiate a ballistic sequence that detonates the perforating charges. 
     In Example 5, the subject matter of Examples 1-4 can further include wherein the extendable member is positioned in an isolated chamber that is pressure isolated from the perforating charges. 
     In Example 6, the subject matter of Examples 1-5 can further include a second extendable member configured to move between the retracted position and the extended position, wherein the second extendable member is configured to engage the surface of the tubular in the second extended position, thereby biasing the centralizing perforating gun away from the surface of and centralized within the tubular, and wherein the extendable member and second extendable member are positioned on opposite longitudinal sides of the perforating charges. 
     In Example 7, the subject matter of Examples 1-6 can further include a first power charge ignitable to extend the extendable member from the retracted position to the extended position. In addition, the subject matter of Examples 1-6 can further include a second power charge ignitable to extend the second extendable member from the second retracted position to the second extended position. 
     In Example 8, the subject matter of Examples 1-7 can further include wherein the extendable member is positioned within the gun housing. 
     In Example 9, the subject matter of Examples 1-8 can further include wherein the extendable member is a bladder positioned around at least a portion of the gun housing. 
     In Example 10, the subject matter of Examples 1-9 can further include wherein detonation of the perforating charges is configured to puncture the bladder. 
     In Example 11, the subject matter of Examples 1-10 can further include wherein the bladder is pressure isolated from the perforating charges. 
     In Example 12, the subject matter of Examples 1-8 can further include wherein the extendable member includes an arm rotatable about a pin to move the arm between the retracted position and the extended position. 
     In Example 13, the subject matter of Examples 1-8 and Example 12 can further include a piston coupled to a portion of the arm such that axial motion of the piston causes rotation of the arm. 
     Example 14 is a method for centralizing a perforating gun comprising conveying the perforating gun that includes a gun housing downhole into a wellbore. The method further includes igniting a power charge to extend an extendable member from a retracted position to engage a surface of a tubular within a wellbore in an extended position, thereby biasing the perforating gun away from the surface of the tubular. Moreover, the method includes detonating a perforating charge positioned within the gun housing to perforate a wellbore. 
     In Example 15, the subject matter of Example 14 can further include extending the extendable member before detonating the perforating charges. 
     In Example 16, the subject matter of Examples 14-15 can further include retracting the extendable member after detonating the perforating charges. 
     In Example 17, the subject matter of Examples 14-16 can further include retracting the extendable member in response to rupturing a rupture disc. 
     In Example 18, the subject matter of Examples 14-17 can further include wherein the extendable member is positioned in a chamber that is pressure isolated from the perforating charges. 
     In Example 19, the subject matter of Examples 14-18 can further include wherein the extendable member is a bladder positioned around at least a portion of the gun housing, and detonating the perforating charges punctures the bladder. 
     Example 20 is a system for perforating a wellbore, the system comprising a wireline and perforating guns positioned along the wireline. Each of the perforating guns includes a gun housing, perforating charges positioned within the gun housing and detonatable to perforate the tubular, and a centralizing system. The centralizing system includes an extendable member configured to move between a retracted position and an extended position. The extendable member is configured to engage a surface of the tubular in the extended position, thereby biasing the centralizing perforating gun away from the surface of the tubular. 
     One or more specific embodiments of the system and method for centralizing a tool in a wellbore have been described. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     Certain terms are used throughout the description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. 
     Reference throughout this specification to “one embodiment,” “an embodiment,” “embodiments,” “some embodiments,” “certain embodiments,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, these phrases or similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     The embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.