Abstract:
The present invention relates to a boltless bonnet assembly for use in a blowout preventer (BOP). In some embodiments, the boltless bonnet assembly includes a bonnet having a forward end facing a ram body of the BOP stack, and a bonnet latch disposed within the bonnet, the bonnet latch attached to the forward end of the bonnet. The boltless bonnet assembly further includes a bonnet positioning mechanism in communication with the bonnet latch to move the bonnet latch into and out of engagement with the ram body.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This technology relates to oil and gas wells, and in particular to a boltless bonnet assembly for a blowout preventer (BOP) for use in wellbore operations. 
         [0003]    2. Brief Description of Related Art 
         [0004]    The existing technologies for extracting fossil fuels use components such as a blowout preventer (BOP) for preventing well blowouts. A typical BOP includes a bore that runs through the BOP and connects to a wellbore. Due to the physical and mechanical demands placed on BOPs in the field, the components of a BOP assembly, such as the BOP rams, need to be examined, adjusted, machined and/or replaced periodically. The BOP bonnet assembly typically must be separated from the ram body of the BOP to allow access to serviceable components such as the ram block. 
         [0005]    The operation of disengaging the BOP bonnets from the ram body can be very laborious, typically requiring specialized tools designed to accommodate connectors such as the large diameter bolts employed in these systems, and therefore requires appreciable time, effort and cost for the technicians and engineers charged with separating the bonnets. In addition, there is a significant concern related to the amount of down time for the rig, which requires the BOP for operation, and the potential millions of dollars that may be lost while the wellbore equipment is idle. Moreover, a wellbore may be located in an environment that may be difficult to access, such as a deep water wellbore, where even greater costs, time, and associated operator safety concerns must be addressed. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention relates to a boltless bonnet assembly for use in a BOP stack. In some embodiments, the boltless bonnet assembly can include a bonnet having a forward end facing a ram body of the BOP stack, a bonnet latch disposed within the bonnet, the bonnet latch attached to the forward end of the bonnet, and a bonnet positioning mechanism in communication with the bonnet latch to move the bonnet latch into and out of engagement with the ram body. 
         [0007]    Alternate embodiments of the boltless bonnet assembly can include a bonnet having a forward end facing a ram body of the BOP stack, a bonnet latch disposed within the bonnet, the bonnet latch attached to the forward end of the bonnet, and a screw operably attached to the bonnet and bonnet latch for driving the bonnet latch into and out of engagement with the ram body. 
         [0008]    Some embodiments of the present invention can further include a method for attaching a bonnet to a ram body of a BOP. The method can include the steps of positioning the bonnet adjacent the ram body, and rotating an engagement/disengagement screw attached to a bonnet latch in a first direction in the bonnet to drive a bonnet latch into engagement with the ram body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    So that the manner in which the features, advantages and objects of the invention, as well as others which will become apparent, are attained, and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof which are illustrated in the appended drawings that form a part of this specification. It is to be noted, however, that the drawings illustrate only a preferred embodiment of the invention and are therefore not to be considered limiting of its scope as the invention may admit to other equally effective embodiments. The present technology will be better understood on reading the following detailed description of nonlimiting embodiments thereof, and on examining the accompanying drawings, in which: 
           [0010]      FIG. 1  is a top view of a BOP assembly according to an embodiment of the present technology; 
           [0011]      FIG. 2  is a top view of the BOP assembly of  FIG. 1  with the bonnet disengaged from a ram body; 
           [0012]      FIG. 3  is an enlarged top cross-sectional view of a boltless bonnet assembly according to an embodiment of the present technology; 
           [0013]      FIG. 4  is an enlarged top cross-sectional view of the boltless bonnet assembly of  FIG. 3  with the bonnet latch disengaged from the body latch; and 
           [0014]      FIG. 5  is a perspective cutaway view of the BOP assembly according to an embodiment of the present technology. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    The foregoing aspects, features, and advantages of the present technology will be further appreciated when considered with reference to the following description of preferred embodiments and accompanying drawings, wherein like reference numerals represent like elements. In describing the preferred embodiments of the technology illustrated in the appended drawings, specific terminology will be used for the sake of clarity. However, the technology is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose. 
         [0016]    A “connector”, in accordance with the present invention, refers to a composition or device capable of adjoining two or more components through one or more machined perforations, insertions, latches and/or welds, including but not limited to threading, perforation, wedge connection and key connection. 
         [0017]    As used herein, the term “boltless” refers to a type of connection or engagement using a connector that lacks or does not require a torqeable bolt, fastener, a hinge, a wedge including a multiple wedge, a lockable key connector or key plate or any other connector capable of reversibly engaging two or more components where at least one of the connectable components possesses a machined perforation or insertion. For instance, a boltless connector does not require the machining of threads or one or more wedge connectors or key plates for adjoining one or more connectable components such as a boltless ram blowout preventer bonnet assembly and/or an operator body. In a preferred embodiment, a boltless connection may be exemplified by a bonnet latch comprising a series of toothed latches for engaging or attaching a boltless ram blowout preventer bonnet assembly to an operator body. 
         [0018]    Referring to  FIG. 1 , there is shown a top view of a BOP assembly, including a ram body  10  and a bonnet  12 . The ram body  10  is attached to the bonnet  12  by a boltless bonnet assembly  14 . The bonnet  12  is in turn attached to additional components of the BOP assembly, such as the BOP rams  16  (shown in  FIG. 2 ).  FIG. 2  depicts an alternate top view of the BOP assembly wherein the bonnet  12  on one side of the ram body  10  is separated from the ram body  10  to provide access to the BOP rams  16 . 
         [0019]    As shown in  FIG. 2 , the bonnet  12  and BOP rams  16  can slide on rollers  17  engaged with rails  18  attached to the ram body  10 . The bonnet  12  can be attached to a swiveling yoke (not shown) that is mechanically connected to the rollers  17  and the rails  18 , but that is free to swivel relative to the rails  18 . Thus, the bonnet  12  can be pulled away from the ram body  10  until the BOP rams  16  are clear of the ram body  10 . Then, the bonnet  12  can swivel to orient the BOP rams  16  in a direction away from the ram body  10 . This provides access to the BOP rams  16  for servicing, replacement, etc. As further shown in  FIG. 2 , some embodiments allow one bonnet  12  and BOP ram  16  to swivel, while other bonnets  12 ′ and BOP rams  16 ′ do not swivel. Thus, an operator can access discrete BOP rams as necessary, without rotating all of the rams associated with a particular BOP assembly. 
         [0020]    Although the ability to remove the bonnet  12  and BOP rams  16  from the ram body  10  may be desirable for purposes of servicing the BOP rams  16 , during normal operations, the bonnet  12  must be fixed relative to the ram body  10  so that the BOP rams can close across the bore  20  of the ram body  10 , as needed. Accordingly, the present technology provides a boltless bonnet assembly  14  that allows for easy attachment and release of the bonnet  12  to and from the ram body  10 . 
         [0021]    Referring now to  FIG. 3 , there is shown an enlarged top cross-sectional view of the boltless bonnet assembly  14 , including a body latch  22 , a bonnet latch  24 , and an engagement/disengagement positioning mechanism, which can optionally be a screw  26 . In some embodiments, the body latch  22  can be bolted to the ram body  10 , although this is not required. The body latch  22  could be attached to the ram body  10  by other appropriate means, or could be integral to the ram body  10 . The engagement/disengagement positioning screw  26  can, in some embodiments, be attached to the bonnet latch  24  by a fastener  25 . The fastener  25  can be inserted through the engagement/disengagement screw  26  and into threaded engagement with the bonnet latch  24 . In the embodiment shown, the fastener  25  is not fixed relative to the engagement/disengagement screw  26  so that the engagement/disengagement screw  26  can rotate independently of the fastener  25 . 
         [0022]    The bonnet latch  24  is contained with a bonnet recess  27  in the bonnet  12 , and may have a length substantially equal to the thickness of the bonnet  12 . The bonnet recess  27  can be shaped to receive the bonnet latch  24  when in a retracted position (discussed below). The bonnet latch  24  includes bonnet latch teeth  28  that engage corresponding body latch teeth  30  on the body latch  22 . Although the bonnet latch teeth  28  and the body latch teeth  30  are shown to be a particular shape in the figures, it is to be understood that the teeth can be any appropriate shape or configuration. In addition, the cross-sectional areas of the individual bonnet latch teeth  28  and body latch teeth  30  can vary from tooth to tooth. 
         [0023]    The engagement/disengagement screw  26  is attached to the bonnet latch  24  by the fastener  25  and extends through the bonnet  12  to an outside surface  29  of the bonnet  12 . The engagement/disengagement screw  26  can be moved axially along axis A x  relative to the bonnet  12  to move the bonnet latch  24  from an engaged position (as shown in  FIG. 3 , wherein the bonnet latch teeth  28  are engaged with the body latch teeth  30 ) and a disengaged position (as shown in  FIG. 4 , wherein the bonnet latch teeth  28  are disengaged from the body latch teeth  30 ). In some embodiments, the engagement/disengagement screw  26  may have external threads that correspond to internal threads in the bonnet  12  so that by rotating the engagement/disengagement screw  26 , the threads drive the engagement/disengagement screw  26  axially toward or away from the ram body  10 . As will be appreciated by the skilled artisan, the use of toothed latches  22 ,  24  to attach the bonnet  12  to the ram body  10  advantageously eliminates the need to attach the bonnet  12  to the ram body  10  using bolts or similar connectors, and reduces the number of parts required for the assembly. 
         [0024]    Referring to  FIG. 4 , and as briefly described above, there is shown the boltless bonnet assembly  14 , including the bonnet latch  24 , the engagement/disengagement screw  26 , and the bonnet  12 . In  FIG. 4 , the bonnet latch  24  is disengaged from the body latch  22  attached to the ram body  10 . 
         [0025]    The toothed bonnet latch  24  and body latch  22 , in addition to reducing the requisite number of parts associated with the boltless bonnet assembly  14  and the ram body  10 , advantageously decrease the human operator time and effort required for disengagement of the boltless bonnet assembly  14  from the ram body  10 . For example, a traditional bonnet assembly, where the bonnet is bolted directly to the ram body  10 , may require 30-50 minutes or more to disassemble from a ram body  10 . This is because each individual bolt must be removed before the bonnet can be separated from the ram body. The boltless bonnet assembly  14  of the present invention, however, may be removed from a ram body  10  in approximately 10 minutes. This is because all that is required is to rotate the engagement/disengagement screw  26  until the bonnet latch teeth  28  disengage from the body latch teeth  30 . Rotation of the engagement/disengagement screw  26  can be accomplished by any method, including, for example, using a remotely operated device (ROV). 
         [0026]    Referring to  FIG. 5 , to better understand the spatial arrangement of the components, there is shown a perspective cutaway view of a boltless ram blowout preventer according to an embodiment of the present technology. As shown, the bonnet latch  24  is engaged with the body latch  22  of the ram body  10  of a blowout preventer assembly. More specifically, the boltless bonnet assembly  14  is shown engaged with a ram body  10  as would occur during normal operations (i.e., when the BOP rams (not shown in  FIG. 5 ) are operably positioned in the ram body  10 ). In  FIG. 5 , a ram cavity  32  is shown in the ram body  10 . The ram cavity  32  is configured to accept the BOP rams  16  (shown in  FIGS. 1 and 2 ). 
         [0027]    Each of the features of the present technology, as described and shown in various combinations in the above-described embodiments, increase the ease with which a bonnet assembly may be operably attached to a ram body for assembling a BOP for wellbore applications. In fact, the boltless ram assembly shown and described herein significantly decreases the time and effort required to assemble and disassemble commonly used, bolt jointed ram BOP bonnets. 
         [0028]    The present technology advantageously reduces the servicing time of the ram block as well as the physical demands associated with the servicing. In addition, the external latching associated with the boltless bonnet assembly of the present invention beneficially allows for easier visual inspection of the engagement of the locking components of the BOP. The elimination of bolts and other connectors further allows the boltless bonnet assembly to exhibit an improved tolerance towards debris and related components that may adversely affect BOP function. 
         [0029]    While the technology has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention. Furthermore, it is to be understood that the above disclosed embodiments are merely illustrative of the principles and applications of the present invention. Accordingly, numerous modifications may be made to the illustrative embodiments and other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. 
         [0030]    The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise. 
         [0031]    “Optional” or “optionally” means that the subsequently described component may or may not be present or the event or circumstances may or may not occur. The description includes instances where the component is present and instances where it is not present, and event or circumstance occurs and instances where it does not occur.