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BACKGROUND 
       [0001]    This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, 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 invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
         [0002]    Blowout preventers (BOPs) are used extensively throughout the oil and gas industry. Typical blowout preventers are used as a large specialized valve or similar mechanical device that seal, control, and monitor oil and gas wells. The two categories of blowout preventers that are most prevalent are ram blowout preventers and annular blowout preventers. Blowout preventer stacks frequently utilize both types, typically with at least one annular blowout preventer stacked above several ram blowout preventers. The ram units in ram blowout preventers allow for both the shearing of the drill pipe and the sealing of the blowout preventer. A blowout preventer stack may be secured to a wellhead and may provide a safe means for sealing the well in the event of a system failure. 
         [0003]    In a typical ram blowout preventer, a ram bonnet assembly may be bolted to the main body using a number of high tensile bolts or studs. These bolts are required to hold the bonnet in position to enable the sealing arrangements to work effectively. During normal operation, the blowout preventers may be subject to pressures up to 20,000 psi, or even higher. To be able to operate against and to contain fluids at such pressures, blowout preventers are becoming larger and stronger. Blowout preventer stacks, including related devices, 30 feet or more in height are increasingly common. Further, ram-type blowout preventers may require interchangeable parts to be used with pipe having different sizes and strengths. Such requirements, if not impractical, may require the presence of personnel at locations that can be hazardous, and may be limited due to particular size or equipment restrictions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    For a detailed description of embodiments of the subject disclosure, reference will now be made to the accompanying drawings in which: 
           [0005]      FIG. 1  shows a sectional view of a blowout preventer; 
           [0006]      FIG. 2  shows a wire cutting apparatus for use within a blowout preventer in accordance with one or more embodiments of the present disclosure; 
           [0007]      FIG. 3  shows a side cross-sectional view of a wire cutting apparatus in a retracted position in a blowout preventer in accordance with one or more embodiments of the present disclosure; 
           [0008]      FIG. 4  shows an above schematic view of a wire cutting apparatus in a retracted position in a blowout preventer in accordance with one or more embodiments of the present disclosure; 
           [0009]      FIG. 5  shows a side cross-sectional view of a wire cutting apparatus in an extended position in a blowout preventer in accordance with one or more embodiments of the present disclosure; 
           [0010]      FIG. 6  shows an above schematic view of a wire cutting apparatus in an extended position in a blowout preventer in accordance with one or more embodiments of the present disclosure; 
           [0011]      FIG. 7  shows an above schematic view of a wire cutting apparatus in a push-type configuration to cut a tubular member in accordance with one or more embodiments of the present disclosure; and 
           [0012]      FIG. 8  shows an above schematic view of a wire cutting apparatus in a pull-type configuration to cut a tubular member in accordance with one or more embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The following discussion is directed to various embodiments of the invention. The drawing figures are not necessarily to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. 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 below may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be an illustration of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment. 
         [0014]    Certain terms are used throughout the following 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 are the same structure or function. 
         [0015]    In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. In addition, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. The use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components. 
         [0016]    Referring now to  FIG. 1 , a sectional view of a blowout preventer  10  is shown. The blowout preventer  10  includes a housing  12 , such as a hollow body, with a bore  14  that enables passage of fluid or a tubular member through the blowout preventer  10 . The housing  12  further includes one or more cavities  16 , such as cavities  16  opposed from each other with respect to the bore  14 , with a ram  18  movably positioned within each cavity  16 . The blowout preventer  10  may be coupled to other equipment that facilitates natural resource production. For instance, production equipment or other components may be attached to the top of the blowout preventer  10  using a connection  20  (which may be facilitated in the form of fasteners), and the blowout preventer  10  may be attached to a wellhead or spool using the flange  22  and additional fasteners. 
         [0017]    One or more bonnet assemblies  24  are secured to the housing  12  and include various components that facilitate control of the rams  18  positioned in the blowout preventer  10 . The bonnet assemblies  24  are coupled to the housing  12  by using one or more fasteners  26  to secure the bonnets  28  of the bonnet assemblies  24  to the housing  12 . The rams  18  are then actuated and moved through the cavities  16 , into and out of the bore  14 , by operating and moving a piston  30  and a rod  32  coupled thereto within a housing  34  of the bonnet assemblies  24 . In operation, a force (e.g., from hydraulic pressure) may be applied to the pistons  30  to drive the rods  32 , which in turn drives the rams  18  coupled thereto into the bore  14  of the blowout preventer  10 . The rams  18  cooperate with one another when driven together to seal the bore  14  and inhibit flow through the blowout preventer  10 . In another embodiment, the rams  18  may be shear rams such that, when driven towards each other, shear a tubular member present within the bore  14  of the housing  12  of the blowout preventer  10 . 
         [0018]    Referring now to  FIG. 2 , a wire cutting apparatus  220  for use within a blowout preventer in accordance with one or more embodiments of the present disclosure is shown. The wire cutting apparatus  220  may be included in a housing of a blowout preventer to cut and shear a tubular member that is positioned within the bore of the blowout preventer. This may involve moving, extending, and retracting the wire cutting apparatus  220  into and out of the bore of the blowout preventer such that the wire cutting apparatus  220  may cut an object (e.g., tubular member) present within the bore of the blowout preventer. The use of a wire cutting apparatus  220  within a blowout preventer may enable the blowout preventer to operating at lower pressures and forces, thereby reducing the size and equipment requirements. 
         [0019]    The wire cutting apparatus  220  in this embodiment includes a cutting wire  222  that is supported by pulleys  224 . An example of a cutting wire  222  may include a diamond impregnated wire, though other types of cutting wire may be used without departing from the scope of the present disclosure. A motor  226  may then be coupled to the pulleys  224  to drive the cutting wire  222 . The pulleys  224  may include a drive pulley  224 A and one or more support pulleys  224 B. The motor  226  may be operatively coupled to the drive pulley  224 A to drive the drive pulley  224 A and the cutting wire  222  supported by the pulleys  224 . 
         [0020]    The wire cutting apparatus  220  may have a frame  228  with the pulleys  224  supported by the frame  228 . In particular, one or more axles of the pulleys  224  may be connected to the frame  228  such that the pulleys  224  are rotatably coupled to the frame  228 . One or more gears may be used with the wire cutting apparatus  220 , such as to control a speed of the cutting wire  222 , as desired. For example, as shown, a gearbox  230  may be included with the wire cutting apparatus  220  with the gearbox  230  coupled between the motor  226  and the drive pulley  224 A. The gearbox  230  may enable the motor  226  to control the speed at which the drive pulley  224 A rotates, and hence, control the speed at which the cutting wire  222  rotates through the wire cutting apparatus  220 . 
         [0021]    As discussed above, the motor  226  may be used to drive the pulleys  224  and the cutting wire  222  though the cutting wire  222 , the pulleys  224 , and the frame  228  move with respect to the motor  226  (e.g., the cutting wire  222  may extend into and out of a bore of a blowout preventer while the motor  226  remains relatively stationary). The wire cutting apparatus  220  may include one or more components or mechanisms to enable this type of movement between the motor  226  and the cutting wire  222 . In this embodiment, a telescoping assembly  232  may be used to operatively couple the motor  226  to the pulleys  224 , and more specifically the drive pulley  224 A. The telescoping assembly  232  may include an inner shaft  234  and an outer shaft  236  (or more shafts as necessary), with the telescoping assembly  232  extending between the motor  226  and the gearbox  230 . This may enable the motor  226  to be operatively coupled to and drive the drive pulley  224 A through the telescoping assembly  232  and the gearbox  230  as the cutting wire  222 , pulleys  224 , and the frame  228  move with respect to the motor  226 . The present disclosure also contemplates other components, mechanisms, and assemblies included within the scope of the present disclosure that may also be used to enable such movement between the motor and the cutting wire, if necessary. 
         [0022]    The wire cutting apparatus  220 , or a blowout preventer including the wire cutting apparatus  220 , may include a drive assembly  240  to move, extend, and retract the wire cutting apparatus  220  into and out of the bore of the blowout preventer. In  FIG. 2 , the drive assembly  240  includes a housing  242  (e.g., such as a bonnet housing of a blowout preventer) with a piston  244  movably positioned within the housing  242 . A rod  246  may then be coupled and extend between the piston  244  and the wire cutting apparatus  220 , or more particularly the frame  228  of the wire cutting apparatus  220  in this embodiment, to enable the piston  244  to move the wire cutting apparatus  220  within a blowout preventer. For example, pressure (e.g., hydraulic pressure) may be selectively introduced on either side of the piston  244  to selectively move the piston  244 , and hence the wire cutting apparatus  220 . The present disclosure also contemplates other types of drive assemblies that may be used to move the wire cutting apparatus  220  within a blowout preventer that are included within the scope of the present disclosure. 
         [0023]    In accordance with one or more embodiments, as the wire cutting apparatus  220  may be included within a blowout preventer, and the blowout preventer may be used subsea, the wire cutting apparatus  220  may include multiple sources to power the wire cutting apparatus  220 . For example, as shown in  FIG. 2 , a remotely-operated vehicle (ROV) drive coupling  238  may be included with the wire cutting apparatus  220 . In this embodiment, the ROV drive coupling  238  may be operatively coupled to the motor  226  to enable an ROV to supplement or provide power to the motor  226 . This may enable additional or alternative power sources to drive the cutting wire  222  of the wire cutting apparatus  220 . Accordingly, in one or more embodiments, the wire cutting apparatus  220  may be able to operate independent of a blowout preventer control system, without power from the surface of the blowout preventer control system, and/or electrical power. In one or more such embodiments, the wire cutting apparatus  220  may not include electrical components or electronics. 
         [0024]    Referring now to  FIGS. 3-6 , a blowout preventer  300  including a wire cutting apparatus  320  in accordance with one or more embodiments of the present disclosure is shown.  FIG. 3  shows a side cross-sectional view of the blowout preventer  300  in a retracted position, and  FIG. 4  shows an above view of the blowout preventer  300  in the retracted position. Further,  FIG. 5  shows a side cross-sectional view of the blowout preventer  300  in an extended position, and  FIG. 6  shows an above view of the blowout preventer  300  in the extended position. 
         [0025]    The blowout preventer  300  includes a housing  302 , in which the housing  302  includes a bore  304  extending through the housing  302  and one or more cavities  306  in the housing  302  that intersect with the bore  304 . The wire cutting apparatus  320  may be movably positioned within the housing  302 , such as within the cavity  306 , of the blowout preventer  300 . The wire cutting apparatus  320  may then move (e.g., extend and retract) into and out of the bore  304  of the housing  302  of the blowout preventer  300 . As such, if an object, such as a tubular member  308 , is included within the bore  304  of the blowout preventer  300 , the wire cutting apparatus  320  may be used to cut or shear the tubular member  308 . 
         [0026]    As discussed above, the wire cutting apparatus  320  includes a wire  322  supported by pulleys  324  with a motor  326  to drive the cutting wire  322  using the pulleys  324 . The wire cutting apparatus  320  may have a frame  328  with the pulleys  324  supported by the frame  328 , and a gearbox  330  may be coupled between the motor  326  and the pulleys  324  to enable the motor  226  to control the speed at which the pulleys  324  (e.g., drive pulley  324 A) rotates, and hence, control the speed at which the cutting wire  322  rotate through the wire cutting apparatus  320 . 
         [0027]    To facilitate the cutting motion of the wire cutting apparatus  320  within the blowout preventer  300 , one or more components, such as a support block  350 , may be included to support the object (e.g., tubular member  308 ) included within the bore  304  of the blowout preventer  300 . The support block  350  is shown as positioned opposite the wire cutting apparatus  320  with respect to the bore  304  of the housing  302  of the blowout preventer  300 . In one or more embodiments, the support block  350  may be movably positioned within the housing  302 , such as within a cavity  306 , of the blowout preventer  300 . The support block  350  may then move (e.g., extend and retract) into and out of the bore  304  of the housing  302  of the blowout preventer  300 . In particular, the support block  350  may extend and retract into and out of the bore  304  along with the wire cutting apparatus  320 . 
         [0028]    As shown, the support block  350  may include in this embodiment a concave-profiled face to facilitate supporting the tubular member  308  by the support block  350 . In this embodiment, the support block  350  is shown as including a “V” profiled type face  352  such that this profile centralizes and/or stabilizes the tubular member  308  against the support block  350 . Further, the support block  350  may include an opening  354  or channel formed therein. This opening  354  may then enable the wire cutting apparatus  320  to be received, at least partially, within and correspond to the support block  350 , as shown particularly in  FIG. 5 , to enable the wire cutting apparatus  320  to fully cut across the tubular member  308 . 
         [0029]    As discussed above, the wire cutting apparatus  320 , or the blowout preventer  300  including the wire cutting apparatus  320 , may include a drive assembly  340  to move, extend, and retract the wire cutting apparatus  320  into and out of the bore  304  of the blowout preventer  300 . In this embodiment, the drive assembly  340  includes a housing  342  with a piston  344  movably positioned within the housing  342 , and a rod  346  coupled and extending between the piston  344  and the wire cutting apparatus  320 . 
         [0030]    Similarly, the support block  350 , or the blowout preventer  300  including the support block  350 , may include a drive assembly  360  to move, extend, and retract the support block  350  into and out of the bore  304  of the blowout preventer  300 . In  FIGS. 3-6 , the drive assembly  360  includes a housing  362  (e.g., such as a bonnet housing of the blowout preventer  300 ) with a piston  364  movably positioned within the housing  362 . A rod  366  may then be coupled and extend between the piston  364  and the support block  350  to enable the piston  364  to move the support block  350  within the blowout preventer  300 . 
         [0031]    In one embodiment, as the support block  350  may extend and retract into and out of the bore  304  along with the wire cutting apparatus  320 , the drive assembly  360  of the support block  350  and the drive assembly  340  of the wire cutting apparatus  320  may be linked to each other, in operation with each other, and/or on the same drive circuit to similarly control the movements of the support block  350  and the wire cutting apparatus  320 . For example, in the embodiment shown here, the hydraulic pressure used to drive the drive assembly  360  may also be used to drive the drive assembly  340 . Further, the present disclosure also contemplates other types of drive assemblies that may be used to move the support block  350  within a blowout preventer that are included within the scope of the present disclosure. 
         [0032]    In one or more embodiments, a wire cutting apparatus may include a tensioning mechanism, such as to maintain a predetermined tension upon the cutting wire. For example, a tensioning mechanism may involve selectively controlling movement of one or more pulleys with respect to each other to maintain a predetermined tension upon the cutting wire across the pulleys. This may facilitate keeping the cutting wire taut, particularly when cutting an object with the cutting wire. 
         [0033]    Further, in one or more embodiments, the wire cutting apparatus and/or the support block may be movable at or with a predetermined constant force within the blowout preventer. For example, when the wire cutting apparatus  320  and the support block  350  are extending into the bore  304  of the blowout preventer  300  to cut the tubular member  308 , the movement of the wire cutting apparatus  320  and/or the support block  350  may be controlled to apply a predetermined constant force upon the tubular member  308 . This may facilitate the cutting motion of the wire cutting apparatus  320  and prevent potential jamming or stalling of the wire cutting apparatus  320 . 
         [0034]    Furthermore, in one or more embodiments, the wire cutting apparatus and/or the support block may be protected, such as from contents included within the bore of the blowout preventer, when not in use and positioned within the bore of the blowout preventer. For example, a flap may be used to cover and/or seal the opening through which the wire cutting apparatus  320  and/or the support block  350  protrude when extending into the bore  304  of the blowout preventer  300 . The flap may enable the wire cutting apparatus  320  and/or the support block  350  to extend into the bore  304  of the blowout preventer  300 , such as by having the flap rotate out of the way. The flap may then rotate back to protect the openings and prevent content from the bore  304  flowing back into the cavities  306  of the blowout preventer  300 . The flap may be biased to close over the openings and then may move out of the way of the wire cutting apparatus  320  and/or the support block  350  when engaged. Alternatively, the flap may be separately controlled to move as the wire cutting apparatus  320  and/or the support block  350  move into and out of the bore  304  of the blowout preventer  300 . 
         [0035]    In one or more embodiments, the wire cutting apparatus and/or the support block may be used to seal the bore of the blowout preventer. For example, after the tubular member  308  is cut with the wire cutting apparatus  320 , the support block  350  may move and extend across the bore  304 . By extending out and across the bore  304 , the support block  350  may be able to seal the bore  304 , such as to prevent fluid from passing through the bore  304  after the tubular member  308  is cut. This may enable the blowout preventer  300  to not only be capable of shearing the tubular member  308  positioned therein, but also capable of sealing the bore  304  within the blowout preventer  300  after the tubular member  308  has been cut. 
         [0036]    Referring now to  FIGS. 7 and 8 , multiple schematic above views of a wire cutting apparatus  720  to cut a tubular member  708  in accordance with one or more embodiments of the present disclosure are shown. In particular,  FIG. 7  shows an embodiment of the wire cutting apparatus  720  in a push-type configuration to cut the tubular member  708 , and  FIG. 8  shows an embodiment of the wire cutting apparatus  720  in a pull-type configuration to cut the tubular member  708 . 
         [0037]    As with the above, the wire cutting apparatus  720  may include a wire  722  supported by pulleys  724  with a motor  726  to drive the cutting wire  722  using the pulleys  724 . A gearbox  730  may be coupled between the motor  726  and the drive pulley  724 A to control the speed at which the cutting wire  722  rotates through the wire cutting apparatus  720 . Further, a telescoping assembly  732  including an inner shaft  734  and an outer shaft  736  (or more shafts as necessary) may extend between the motor  726  and the gearbox  730 . 
         [0038]    In the above embodiments, and in  FIG. 7 , the wire cutting apparatus  720  may be used in the push-type configuration to cut the tubular member  708 , in which the wire cutting apparatus  720  is pushed (e.g., extended) into the bore of the blowout preventer to contact and cut the tubular member  708 . In another embodiment, and in  FIG. 8 , the wire cutting apparatus  720  may be used in the pull-type configuration to cut the tubular member  708 , in which the wire cutting apparatus  720  is pulled (e.g., retracted) from or out of the bore of the blowout preventer to contact and cut the tubular member  708 . In such an embodiment, the cutting wire  722  may be positioned within the bore of the blowout preventer to have the tubular member  708  received into a loop formed by the cutting wire  722 . Then, once desired, the wire cutting apparatus  720  may be retracted out of the bore of the blowout preventer to have the cutting wire  722  contact and cut the tubular member  708 . Accordingly, a blowout preventer in accordance with the present disclosure may employ either of these types of configurations without departing from the scope of the present disclosure. 
         [0039]    As mentioned above, a blowout preventer in accordance with the present disclosure may be able to operate at lower pressures and with lower forces, such as due to the use of a wire cutting apparatus. This may reduce the size and equipment requirements necessary for the use of a blowout preventer, in particular in a subsea environment where higher pressures and higher forces are often necessary for the shearing of tubular members. 
         [0040]    Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.

Summary:
An apparatus includes a blowout preventer housing comprising a bore extending therethrough and a cavity intersecting the bore and a wire cutting apparatus with a cutting wire. The wire cutting apparatus is movably positionable within the cavity of the blowout preventer housing and is extendable into the bore of the blowout preventer housing.