Patent Publication Number: US-2021172277-A1

Title: Systems and methods for retraction of a packer assembly of an annular blowout preventer

Description:
BACKGROUND 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     An annular blowout preventer (BOP) is installed on a wellhead to seal and control an oil and gas well during drilling operations. A drill string may be suspended inside the oil and gas well from a rig through the annular BOP into the wellbore. During drilling operations, a drilling fluid is delivered through the drill string and returned up through an annulus between the drill string and a casing that lines the wellbore. In the event of a rapid invasion of formation fluid in the annulus, commonly known as a “kick,” the annular BOP may be actuated to seal the annulus and to control fluid pressure in the wellbore. In this way, the annular BOP may protect well equipment disposed above the annular BOP. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein: 
         FIG. 1  is a block diagram of a mineral extraction system, in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a cross-sectional side view of an embodiment of an annular BOP that may be used in the mineral extraction system of  FIG. 1 , wherein the annular BOP includes multiple cables coupled to a packer, and the annular BOP is in an open position; 
         FIG. 3  is a cross-sectional side view of the annular BOP of  FIG. 2 , wherein the annular BOP is in a closed position; 
         FIG. 4  is a cross-sectional side view of an embodiment of the annular BOP that may be used in the mineral extraction system of  FIG. 1 , wherein the annular BOP includes the multiple cables coupled to multiple inserts, and the annular BOP is in the open position; 
         FIG. 5  is a cross-sectional side view of the annular BOP of  FIG. 3 , wherein the annular BOP is in the closed position; 
         FIG. 6  is a cross-sectional side view of an embodiment of the annular BOP that may be used in the mineral extraction system of  FIG. 1 , wherein the annular BOP includes multiple rods coupled to the multiple inserts, and the annular BOP is in the open position; 
         FIG. 7  is a cross-sectional side view of the annular BOP of  FIG. 4 , wherein the annular BOP is in the closed position; 
         FIG. 8  is a side view of an embodiment of one of the multiple inserts of  FIGS. 6 and 7 ; 
         FIG. 9  is a cross-sectional side view of an embodiment of the annular BOP that may be used in the mineral extraction system of  FIG. 1 , wherein the annular BOP includes a normally-closed packer assembly, and the annular BOP is in the closed position; 
         FIG. 10  is a cross-sectional side view of the annular BOP of  FIG. 9 , wherein the annular BOP is in the open position; 
         FIG. 11  is a cross-sectional side view of an embodiment of the annular BOP that may be used in the mineral extraction system of  FIG. 1 , wherein the annular BOP includes multiple rods coupled to respective radially-outer surfaces of multiple inserts, and the annular BOP is in the open position; and 
         FIG. 12  is a cross-sectional side view of the annular BOP of  FIG. 11 , wherein the annular BOP is in the closed position. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments of the present disclosure will be described below. These described embodiments are only exemplary of the present disclosure. Additionally, in an effort to provide a concise description of these exemplary 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. 
     The present embodiments are generally related to annular blowout preventers (BOPs). In particular, the present embodiments are generally directed to a retraction system for annular BOPs. The retraction system may include a connector assembly with a linkage that extends between and couples a piston of the annular BOP to at least one of a packer of the packer assembly of the annular BOP or an insert of the packer assembly of the annular BOP. For example, the retraction system may include at least one cable (e.g., wire; bendable or flexible cable) that extends between and couples the piston to the packer. In some embodiments, the retraction system may include at least one cable that extends between and couples the piston to at least one of the inserts. In some embodiments, the retraction system may include at least one rod (e.g., rigid rod or bar) that extends between and couples the piston to at least one of the inserts. 
     The retraction system may facilitate retraction (e.g., withdrawal) of the packer assembly from a central bore of the annular BOP to thereby facilitate transition of the annular BOP from a closed position to an open position. In some embodiments, the retraction system may be used with a normally-closed packer assembly that is configured to seal the central bore of the annular BOP as a default position (e.g., default configuration; resting position or configuration). Then, the retraction system may be operated to retract the packer assembly from the central bore to thereby cause the annular BOP to transition from the closed position to the open position. Such a configuration may enable the annular BOP to be in the closed position as the default position to protect equipment positioned above the annular BOP and to be in the open position at certain times and/or during certain operations. 
     While the disclosed embodiments are described in the context of a drilling system and drilling operations to facilitate discussion, it should be appreciated that the annular BOP may be adapted for use in other contexts and other operations. For example, the annular BOP may be used in a pressure control equipment (PCE) stack that is coupled to and/or positioned vertically above a wellhead during various intervention operations (e.g., inspection or service operations), such as wireline operations in which a tool supported on a wireline is lowered through the PCE stack to enable inspection and/or maintenance of a well. In such cases, the annular BOP may be in the closed position (e.g., to seal about the wireline extending through the PCE stack) to isolate the environment, as well as other surface equipment, from pressurized fluid within the well. In the present disclosure, a conduit may be any of a variety of tubular or cylindrical structures, such as a drill string, wireline, Streamline™, slickline, coiled tubing, or other spoolable rod. 
     With the foregoing in mind,  FIG. 1  is a block diagram of an embodiment of a mineral extraction system  10 . The mineral extraction system  10  may be configured to extract various minerals and natural resources, including hydrocarbons (e.g., oil and/or natural gas), from the earth, or to inject substances into the earth. The mineral extraction system  10  may be a land-based system (e.g., a surface system) or an offshore system (e.g., an offshore platform system). A BOP assembly  16  is mounted to a wellhead  18 , which is coupled to a mineral deposit  25  via a wellbore  26 . The wellhead  18  may include any of a variety of other components such as a spool, a hanger, and a “Christmas” tree. The wellhead  18  may return drilling fluid or mud to the surface  12  during drilling operations, for example. Downhole operations are carried out by a conduit  24  that extends through the BOP assembly  16 , through the wellhead  18 , and into the wellbore  26 . 
     To facilitate discussion, the BOP assembly  16  and its components may be described with reference to an axial axis or direction  30 , a radial axis or direction  32 , and a circumferential axis or direction  34 . The BOP assembly  16  may include one or more annular BOPs  42 . A central bore  44  (e.g., flow bore) extends through the one or more annular BOPs  42 . As discussed in more detail below, at least one of the annular BOPs  42  may include a retraction system that has a connector assembly that couples a piston to a packer assembly (e.g., to a packer and/or an insert of the packer assembly). The retraction system may facilitate retraction of the packer assembly from the central bore  44  of the annular BOP  42 . Thus, the retraction system may facilitate transition of the annular BOP  42  from a closed position in which the packer assembly blocks a fluid flow through the central bore  44  (e.g., seals an annulus about the conduit  24  disposed in the central bore  44 ; seals the central bore  44 ) to an open position in which the packer assembly is withdrawn from the central bore  44  (e.g., does not block the fluid flow through the central bore  44 ; does not seal the annular or the central bore  44 ). 
       FIGS. 2 and 3  each show a cross-sectional side view of an embodiment of the annular BOP  42  that may be used in the system  10  of  FIG. 1 . In  FIG. 2 , the annular BOP  42  is in an open position  50  (e.g., open configuration). In  FIG. 3 , the annular BOP  42  is in a closed position  52  (e.g., closed configuration). In the open position  50 , the annular BOP  42  may enable fluid flow through the central bore  44  of the annular BOP  42 . In the closed position  52 , the annular BOP  42  may block fluid flow through the central bore  44  of the annular BOP  42 . 
     As shown, the annular BOP  42  includes a housing  54  (e.g., annular housing) having a body  56  (e.g., body portion) and a top  58  (e.g., top portion) coupled to the body  56 . A packer assembly  62  (e.g., annular packer assembly) within the housing  54  may include a packer  64  (e.g., annular packer; packing element) and multiple inserts  66 . The packer  64  may be a flexible component (e.g., elastomer) and the multiple inserts  66  may be rigid components (e.g., metal or metal alloy). The multiple inserts  66  may extend axially through the packer  64  and may be positioned at discrete circumferential locations about the packer  64 . 
     The annular BOP  42  may also include a piston  68  (e.g., annular piston) within the housing  54 . An adapter  70  (e.g., annular adapter) may be positioned between the body  56  and the top  58 , and various seals  72  (e.g., annular seals) may be provided in the body  56 , the top  58 , the piston  68 , and/or the adapter  70  to seal spaces  74 ,  76  (e.g., annular spaces) from the central bore  44  and from one another. 
     The annular BOP  42  further includes a retraction system  80 . The retraction system  80  may include a connector assembly  82  that connects or couples the packer assembly  62  to the piston  68 . In the illustrated embodiment, the connector assembly  82  includes multiple cables  84  (e.g., wires; flexible or bendable cables; linkage). Each cable  84  includes a first end portion  86  that contacts and/or is coupled to the piston  68  and a second end portion  88  that contacts and/or is coupled to the packer  64 . For example, the first end portion  86  may be fastened to the piston  68  (e.g., via a bonding agent, a weld, and/or a mechanical fastener), and the second end portion  88  may be fastened to the packer  64  (e.g., via a bonding agent and/or a mechanical fastener) and/or embedded in the packer  64  (e.g., embedded in and surrounded by the elastomer of the packer  64 ). In some embodiments, the first end portion  86  may be pivotally coupled (e.g., via a pivot) to the piston  68 . 
     In operation, the piston  68  is configured to move relative to the housing  54  in the axial direction  30 . For example, a fluid (e.g., a liquid and/or gas) may be provided to the space  76  via a first fluid conduit  100  to drive the piston  68  upward in the axial direction  30 , as shown by arrow  102  in  FIG. 2 . As the piston  68  moves upward, the piston  68  drives the packer assembly  62  upward. For example, an axially-facing surface  104  (e.g., packer-contacting surface, top surface, upper surface, or annular surface) of the piston  68  may apply an upward force against an axially-facing surface  106  (e.g., piston-contacting surface, bottom surface, lower surface, or annular surface) of the packer assembly  62 , driving the packer assembly  62  upward. When driven upward by the piston  68 , the packer assembly  62  may move upward and inward within the top  60  until the packer  64  seals around the conduit  24  extending through the central bore  44  or closes off the central bore  44 , thereby causing the annular BOP  42  to be in the closed position  52 . 
     A second fluid conduit  108  is configured to provide a fluid (e.g., a liquid and/or gas) to the space  74  to drive the piston  68 , as well as the cable  84  and the packer assembly  62  coupled thereto, downward. Because the cable  84  is coupled to both the packer  64  and the piston  68 , the cable  84  may exert a force on the packer assembly  62  that drives and/or pulls the packer assembly  62  downward as the piston  68  moves downward (e.g., the packer assembly  62  and the piston  68  move downward together). As the packer assembly  62  moves downward, the packer assembly  62  may also expand and/or move outwardly within the top  60  (e.g., due to a curvature of the top  60 ). In this way, the packer assembly  62  may be retracted (e.g., withdrawn or pulled) from the central bore  44  and may cause the annular BOP  42  to move into the open position  50 . 
     Without the cable  84 , at least a portion of the packer assembly  62  (e.g., a larger portion as compared to the present embodiments that have the cable  84 ) may remain within the central bore  44 . It should be appreciated that the piston  68  and associated components (e.g., the spaces  74 ,  76 ; the fluid conduits  100 ,  108 ; an electronic controller having a processor and memory that coordinates the delivery of the fluid to the spaces  74 ,  76 ) that cause adjustment of the connector assembly  82  may be considered part of the retraction system  80 . 
     It should also be appreciated that the annular BOP  42  may include any number of cables  84 . For example, the annular BOP  42  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more cables  84  positioned at discrete circumferential locations of the packer assembly  62  and the piston  68  (e.g., evenly or unevenly spaced along the circumferential axis  34 ). As shown, each cable  84  may be coupled to a center portion  110  of the packer  64 . The center portion  110  may be approximately midway between a radially-inner surface (e.g., innermost surface; annular surface) and a radially-outer surface (e.g., outermost surface; annular surface) of the packer  64  and/or approximately midway between an axially-upper surface (e.g., uppermost surface; annular surface) and an axially-lower surface (e.g., lowermost surface; annular surface; the axially-facing surface  106 ) of the packer  64 . This may enable the cable  84  to exert the force at the center portion  110  of the packer  64 , which may in turn facilitate withdrawal of the packer assembly  62  from the central bore  44  (e.g., as opposed to coupling the cable  84  to the axially-facing surface  106  or to some other exterior surface or portion of the packer assembly  62 ). Furthermore, as shown, each cable  84  may be coupled to an axially-upper surface (e.g., uppermost surface; annular surface; the axially-facing surface  104 ) of the piston  68 , which may contact the packer assembly  62  in the open position  50 , the closed position  52 , or both. 
     It should be appreciated that the cables  84  may be coupled to the packer  64  at any suitable portion of the packer  64  and may be coupled to the piston  68  at any suitable portion of the piston  68 . For example, the cable  84  may be couple to the packer  64  at the axially-facing surface  106  of the packer assembly  62 , at the radially-outer surface of the packer assembly  62 , or at some other portion of the packer assembly  62  and/or the packer  64 . Furthermore, in some embodiments, the packer assembly  62  and/or the packer  64  may be coupled to the piston  68  without the cable  84 , such as via a linkage that includes a bonding agent (e.g., that bonds the surfaces  104 ,  106  together), a weld (e.g., that welds the surfaces  104 ,  106  together), and/or a mechanical fastener (e.g., that extends between and contacts the surfaces  104 ,  106  to join the packer assembly  62  to the piston  68 ). 
     Additionally or alternatively the connector assembly  82  may include one or more cables  84  coupled to the inserts  66 .  FIGS. 4 and 5  each show a cross-sectional side view of an embodiment of the annular BOP  42  that may be used in the system  10  of  FIG. 1 , wherein multiple cables  84  are coupled to the inserts  66  of the packer assembly  62 . In  FIG. 4 , the annular BOP  42  is in the open position  50 . In  FIG. 5 , the annular BOP  42  is in the closed position  52 . 
     As shown, each cable  84  may include the first end portion  86  that contacts and/or is coupled to the piston  68  and the second end portion  88  that contacts and/or is coupled to the insert  66 . For example, the first end portion  86  may be fastened to the piston  68 , and the second end portion  88  may be fastened to the insert  66  (e.g., via a bonding agent, a weld, and/or a mechanical fastener). In some embodiments, the first end portion  86  may be pivotally coupled (e.g., via a pivot) to the piston  68  and/or the second end portion  88  may be pivotally coupled to the insert  66 . 
     In response to the fluid being provided to the space  76  via the first fluid conduit  100 , the piston  68  and the packer assembly  62  may move upward in the axial direction  30 . When driven upward, the packer assembly  62  may move upward and inward within the top  60  until the packer  64  seals around the conduit  24  extending through the central bore  44  or closes off the central bore  44 , thereby causing the annular BOP  42  to be in the closed position  52 . In response to the fluid being provided to the space  74  via the second fluid conduit  108 , the piston  68  and the packer assembly  62  may move downward. In particular, the cable  84  may exert a force on the packer assembly  62  that drives and/or pulls the packer assembly  62  downward as the piston  68  moves downward (e.g., the packer assembly  62  and the piston  68  move downward together). As the packer assembly  62  moves downward, the packer assembly  62  may also expand and/or move outwardly within the top  60  (e.g., due to a curvature of the top  60 ). In this way, the packer assembly  62  may be retracted (e.g., withdrawn or pulled) from the central bore  44  and may cause the annular BOP  42  to move into the open position  50 . 
     Without the cable  84 , at least a portion of the packer assembly  62  (e.g., a larger portion as compared to the present embodiments that have the cable  84 ) may remain within the central bore  44 . It should be appreciated that the annular BOP  42  may include any number of cables  84 . For example, the annular BOP  42  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more cables  84  positioned at discrete circumferential locations of the packer assembly  62  and the piston  68  (e.g., evenly or unevenly spaced along the circumferential axis  34 ). 
     As shown, each cable  84  may be coupled to a radially-outer surface  112  (e.g., curved surface; annular surface) of the insert  66 . In some embodiments, each cable  84  may be coupled to the radially-outer surface  112  of the insert  66  that is exposed (e.g., uncovered by the packer  64 ) in the open position  50 , the closed position  52 , or both. Furthermore, the cable  84  may be coupled to a center portion  114  of the radially-outer surface  112  that is approximately midway between an axially-upper end (e.g., uppermost end portion) and an axially-lower surface (e.g., lowermost end portion) of the insert  66 . This may enable the cable  84  to exert the force at the radially-outer surface  112  and at the center portion  114  of the insert  66 , which may in turn facilitate withdrawal of the packer assembly  62  from the central bore  44  (e.g., as opposed to coupling the cable  84  to the axially-lower surface or to some other surface or portion of the insert  66 ). Furthermore, as shown, each cable  84  may be coupled to a radially-outer surface (e.g., radially-outermost surface; annular surface) and/or an axially-upper surface (e.g., uppermost surface; annular surface; the axially-facing surface  104 ) of the piston  68  that may contact the packer assembly  62  in the open position  50 , the closed position  52 , or both. Thus, in the illustrated embodiment, the cable  84  is positioned between a radially-inner surface of the housing  54  (e.g., a curved surface of the top  58 ) and a radially-outer surface of the packer assembly  62 , and the cable  84  generally wraps around a portion of the packer assembly  62 . 
     However, it should be appreciated that the cables  84  may be coupled to the insert  66  at any suitable portion of the insert  66  and may be coupled to the piston  68  at any suitable portion of the piston  68 . For example, the cable  84  may be couple to the insert  66  at a portion of the insert  66  that is embedded within the packer  64  or at some other portion of the insert  66 . Furthermore, the annular BOP  42  may have a structure in which the insert  66  and the piston  68  are in contact with one another. In some such cases, the insert  66  and the piston  68  may be coupled to one another without the cable  84 , such as via a linkage that includes a bonding agent (e.g., that bonds surfaces of the insert  66  and the piston  68  together), a weld (e.g., that welds the surfaces of the insert  66  and the piston  68  together), and/or a mechanical fastener (e.g., that extends between and contacts the surfaces of the insert  66  and the piston  68  to join the packer assembly  62  to the piston  68 ). 
     The connector assembly  82  may have any of a variety of other configurations. For example,  FIGS. 6 and 7  each show a cross-sectional side view of an embodiment of the annular BOP  42  that may be used in the system  10  of  FIG. 1 , wherein the connector assembly  82  includes multiple rods  150  (e.g., rigid rods; linkage) coupled to the inserts  66  of the packer assembly  62 . In  FIG. 6 , the annular BOP  42  is in the open position  50 . In  FIG. 7 , the annular BOP  42  is in the closed position  52 . 
     As shown, each rod  150  includes a first end portion  152  that contacts and/or is coupled to the piston  68  and a second end portion  154  that contacts and/or is coupled to the insert  66 . For example, the first end portion  152  may be fastened to the piston  68 , and the second end portion  154  may be fastened to the insert  66 . In response to the fluid being provided to the space  76  via the first fluid conduit  100 , the piston  68  and the packer assembly  62  may move upward in the axial direction  30 . When driven upward, the packer assembly  62  may move upward and inward within the top  60  until the packer  64  seals around the conduit  24  extending through the central bore  44  or closes off the central bore  44 , thereby causing the annular BOP  42  to be in the closed position  52 . In response to the fluid being provided to the space  74  via the second fluid conduit  108 , the piston  68  and the packer assembly  62  may move downward. In particular, the rod  150  may exert a force on the packer assembly  62  that drives and/or pulls the packer assembly  62  downward as the piston  68  moves downward (e.g., the packer assembly  62  and the piston  68  move downward together). As the packer assembly  62  moves downward, the packer assembly  62  may also expand and/or move outwardly within the top  60  (e.g., due to a curvature of the top  60 ). In this way, the packer assembly  62  may be retracted (e.g., withdrawn or pulled) from the central bore  44  and may cause the annular BOP  42  to move into the open position  50 . 
     Without the rod  150 , at least a portion of the packer assembly  62  (e.g., a larger portion as compared to the present embodiments that have the rod  150 ) may remain within the central bore  44 . It should be appreciated that the annular BOP  42  may include any number of rods  150 . For example, the annular BOP  42  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more rods  150  positioned at discrete circumferential locations of the packer assembly  62  and the piston  68  (e.g., evenly or unevenly spaced along the circumferential axis  34 ). As shown, each rod  150  may be coupled to a center portion  156  of the insert  66 . The center portion  156  may be approximately midway between a radially-inner surface (e.g., innermost surface; annular surface) and a radially-outer surface (e.g., outermost surface; annular surface) of the insert  66  and/or approximately midway between an axially-upper end (e.g., uppermost end portion) and an axially-lower end (e.g., lowermost end portion) of the insert  66 . The center portion  156  may be embedded within the packer  64 , and thus, the rod  150  may extend through the packer  64 . This may enable the rod  150  to exert the force at the center portion  156  of the insert  166 , which may in turn facilitate withdrawal of the packer assembly  62  from the central bore  44  (e.g., as opposed to coupling the rod  150  to some other surface or portion of the insert  66 ). Furthermore, as shown, each rod  150  may extend from an axially-upper surface (e.g., uppermost surface; annular surface; the axially-facing surface  104 ) of the piston  68 , which may contact the packer assembly  62  in the open position  50 , the closed position  52 , or both. However, it should be appreciated that the rod  150  may be coupled to the insert  66  at any suitable portion of the insert  66  and may be coupled to the piston  68  at any suitable portion of the piston  68 . 
     To enable the packer assembly  62  to move upward and inward into the central bore  44  (e.g., inward relative to the piston  68 ), at least the second end portion  154  of the rod  150  may be pivotally (e.g., rotatably) coupled to the insert  66  via a pivot  158  (e.g., pivot assembly; pin). Thus, as the piston  68  drives the packer assembly  62  upward, the insert  66  may rotate in a direction of arrow  160  about the pivot  158  (e.g., relative to the rod  150 , the piston  68 , and/or the housing  54 ). Similarly, as the piston  68  and the rod  150  pull the packer assembly  62  downward, the insert  66  may rotate in a direction opposite of the arrow  160  about the pivot  158 . This configuration enables the piston  68  to move along the axial axis  30  and enables the packer assembly  62  to move upward and inward into the central bore  44 , while the piston  68  and the packer assembly  62  are coupled to one another via the connector assembly  82 . 
     In some embodiments, at least the first end portion  152  of the rod  150  may be pivotally coupled to the piston  68  via a pivot  159  (e.g., pivot assembly; pin). In operation, as the piston  68  drives the packer assembly  62  upward, the rod  150  may rotate in a direction of arrow  161  about the pivot  159  (e.g., relative to the rod  150 , the piston  68 , and/or the housing  54 ). Similarly, as the piston  68  and the rod  150  pull the packer assembly  62  downward, the rod  150  may rotate in a direction opposite of the arrow  161  about the pivot  159 . In some embodiments, as shown, the second end portion  154  of the rod  150  may be pivotally coupled to the insert  66  via the pivot  158 , and the first end portion  152  of the rod  150  may be pivotally coupled to the piston  68  via the pivot  159 . However, in some embodiments, at least one of the pivots  158 ,  159  may be replaced by a fixed (e.g., non-rotatable) connection. For example, each rod  150  may be supported within (e.g., threaded into) a recess formed in the axially-upper surface of the piston  68 . 
     With reference to  FIG. 8 , the connector assembly  82  may be coupled to a side surface  162  (e.g., circumferentially-facing surface) of the insert  66 . For example, the pivot  158  may be a pin that extends into the insert  66  from the side surface  162  and that enables rotation of the insert  66  relative to the rod  150 . Thus, in operation, the insert  66  may rotate relative to the rod  150  in the direction of the arrow  160  and in the direction opposite of the arrow  160  as the piston  68  moves along the axial axis  30  to adjust the annular BOP  42  between the open position  50  and the closed position  52  ( FIGS. 6 and 7 ). The connector assembly  82  may also be coupled to the piston  68  via the pivot  159 , which may include a pin supported on a bracket, and which enables rotation of the rod  150  relative to the piston  68 . Thus, in operation, the rod  150  may rotate relative to the piston  68  in the direction of arrow  161  and in the direction opposite of the arrow  161  as the piston  68  moves along the axial axis  30  to adjust the annular BOP  42  between the open position  50  and the closed position  52  ( FIGS. 6 and 7 ). 
       FIG. 9  is a cross-sectional side view of an embodiment of the annular BOP  42  that may be used in the system  10  of  FIG. 1 , wherein the annular BOP  42  includes a normally-closed packer assembly  200  (e.g., annular packer assembly) and is in the closed position  52 .  FIG. 10  is a cross-sectional side view of the annular BOP  42  of  FIG. 9 , wherein the annular BOP  42  is in the open position  50 . 
     In some embodiments, the retraction system  80  may be used with the normally-closed packer assembly  200  that is configured (e.g., shaped; molded) to seal the central bore  44  of the annular BOP  42  as a default position (e.g., default configuration; a resting position or configuration). That is, in the absence of external downward forces from the retraction system  80 , a shape (e.g., a molded shape) of the normally-closed packer assembly  200  may cause the normally-closed packer assembly  200  to extend into the central bore  44 , block the fluid flow through the central bore  44 , seal against the conduit  24 , and/or otherwise seal the central bore  44  (e.g., in the absence of the conduit  24 ) to place the annular BOP  42  in the closed position  52 . Thus, while the retraction system  80  may include the piston  68 , the piston  68  may not drive the normally-closed packer assembly  200  to the position illustrated in  FIG. 9  to adjust the annular BOP  42  to the closed position  52 . Instead, the piston  68  may merely support the normally-closed packer assembly  200  while the normally-closed packer assembly  200  is in the default position. 
     In some such cases, the normally-closed packer assembly  200  may have a shape that does include a central opening at manufacture, but the central opening is closed upon installation within the annular BOP  42 , and/or in the default position. For example, opposing radially-inner walls of the normally-closed packer assembly  200  may contact one another and seal against one another at manufacture and/or upon installation within the annular BOP  42 . Then, the normally-closed packer assembly  200  may be selectively and/or temporarily driven or pulled by the retraction system  80  as disclosed herein, which may cause the radially-inner walls of the normally-closed packer assembly  200  to separate from one another to form the central opening (e.g., the normally-closed packer assembly  200  may become annular) that may align with the central bore  44  to enable passage of the conduit  24 . 
     In particular, the retraction system  80  may be operated to retract the normally-closed packer assembly  200  to thereby cause the annular BOP  42  to transition from the closed position  52  of  FIG. 9  to the open position  50  of  FIG. 10 . For example, a fluid conduit  202  is configured to provide a fluid (e.g., a liquid and/or gas) to a space  204  (e.g., annular space) to drive the piston  68 , as well as the rod  150  and the normally-closed packer assembly  200  coupled thereto, downward. Because the rod  150  coupled to both the insert  66  and the piston  68 , the rod  150  may exert a force on the normally-closed packer assembly  200  that drives and/or pulls the normally-closed packer assembly  200  downward as the piston  68  moves downward (e.g., the normally-closed packer assembly  200  and the piston  68  move downward together). As the normally-closed packer assembly  200  moves downward, the normally-closed packer assembly  200  may also expand and/or move outwardly within the top  60  (e.g., due to a curvature of the top  60 ). In this way, the normally-closed packer assembly  200  may be retracted (e.g., withdrawn or pulled) from the central bore  44  and may cause the annular BOP  42  to move into the open position  50 . Such a configuration may enable the annular BOP  42  to be in the closed position  52  as the default position to protect equipment positioned above the annular BOP  42  and to be in the open position  50  only at certain times and/or during certain operations (e.g., temporarily; upon an input by an operator; via an electronic controller that instructs the provision of the fluid to adjust the normally-closed packer assembly  200 , such as to enable the conduit  24  to extend through the central bore  44 ). In this way, the retraction system  80  may enable use of the normally-closed packer assembly  200  within the annular BOP  42 . 
     As shown, the normally-closed packer assembly  200  may include a packer  206  (e.g., annular packer) and multiple inserts  208 . It should be appreciated that the annular BOP  42  may include any number of rods  150 . For example, the annular BOP  42  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more rods  150  positioned at discrete circumferential locations of the normally-closed packer assembly  200  and the piston  68  (e.g., evenly or unevenly spaced along the circumferential axis  34 ). While the illustrated embodiment includes the rod  150  of  FIGS. 6-8  to facilitate discussion, it should be appreciated that the cable  84  of  FIGS. 2-5  may be utilized in addition to or as an alternative to the rod  150 . 
     Furthermore, the normally-closed packer assembly  200  may be driven out of the central bore  44  or may be adjusted to otherwise accommodate the conduit  24  in other ways. For example, the normally-closed packer assembly  200  may seal the central bore  44  in the absence of the conduit  24  and/or in the absence of the force from the retraction system  80 . Then, the conduit  24  may be driven or pushed into the central bore  44  (e.g., during stripping operations), and the conduit  24  may push the normally-closed packer assembly  200  radially-outwardly and/or downwardly (and, in some cases, the rod  150  and the piston  68  downwardly) so that the conduit  24  may pass through the normally-closed packer assembly  200 . In some embodiments, the normally-closed packer assembly  200  may not seal the central bore  44  in the absence of the conduit  24 , but instead may seal against the conduit  24  as the default position. In such cases, the normally-closed packer assembly  200  may then be driven away from the conduit  24  and out of the central bore  44  to adjust the annular BOP  42  to the open position  50 . 
     It is envisioned that the retraction system  80  disclosed herein may be adapted for use in any of a variety of annular BOPs  42  having any of a variety of structural features. For example,  FIGS. 11 and 12  each show a cross-sectional side view of an embodiment of the annular BOP  42  that may be used in the system  10  of  FIG. 1 , wherein the connector assembly  82  includes multiple rods  150  coupled to respective radially-outer surfaces  220  of inserts  222  of a normally-closed packer assembly  224 . In  FIG. 11 , the annular BOP  42  is in the open position  50 . In  FIG. 12 , the annular BOP  42  is in the closed position  52 . 
     The normally-closed packer assembly  224  may include the inserts  222  and a packer  226 , and the normally-closed packer assembly  224  may be configured (e.g., shaped; molded) to seal the central bore  44  of the annular BOP  42  as a default position (e.g., default configuration; a resting position or configuration). The normally-closed packer assembly  224  may include any of the features and operational characteristics of the normally-closed packer assembly  200  of  FIGS. 9 and 10 . Additionally, while the illustrated embodiment includes the rod  150  of  FIGS. 6-10  to facilitate discussion, it should be appreciated that the cable  84  of  FIGS. 2-5  may be utilized in addition to or as an alternative to the rod  150 . 
     The retraction system may also be adapted for use in annular BOPs having iris-style inserts (e.g., that rotate radially-inwardly as the annular BOP moves from the open position to the closed position). Accordingly, it should be understood that the annular BOP of  FIGS. 1-10  is merely exemplary and are not intended to be limiting. For example, the housing, the packer, and/or the multiple inserts may have various other shapes and configurations. 
     It should also be understood that any of the various components, features, or characteristics illustrated or described above with respect to  FIGS. 1-10  may be combined. For example, the annular BOP may include the cables and/or the rods. Furthermore, the annular BOP may include the cables coupled to the packer and/or to the inserts. Any of the disclosed embodiments may enable the annular BOP to be positively opened via the retraction system and/or to be normally closed to thereby protect components positioned above the annular BOP, among other advantages. For example, the annular BOP and the retraction system of  FIGS. 11 and 12  may be utilized without a normally-closed packer assembly (i.e., the packer assembly may not be molded to be normally-closed as a default position). Similarly, any of the annular BOPs in  FIGS. 2-8  may be utilized with a normally-closed packer assembly (i.e., the packer assembly may be molded to be normally-closed as a default position). 
     While the disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims. 
     The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).