Abstract:
Specialized tools and methods are presented for use on blowout preventers on oil and gas rigs. The specialized tools releseably attach to a threaded, blowout-preventer head to remove the same. In one instance, the tool has a longitudinal shaft, a lifting eye member at one end and a head-mounting member at the other. The head-mounting member attaches to the threaded, blowout-preventer head. In some instances, one or more torque arms may be included to add additional torque. Other embodiments and methods are also included.

Description:
RELATED APPLICATION 
       [0001]    The present application claims the benefit, under 35 U.S.C. §119(e), of the filing of U.S. Provisional Patent Application Ser. No. 61/511,832, entitled “Annular Seal Removing Tool Using Top Drive or Kelly,” filed Jul. 26, 2011, and which incorporated herein by reference for all purposes. 
     
    
     FIELD 
       [0002]    The disclosure herein relates to blowout preventers for use on oil rigs, and more particularly, but not by way of limitation, to blowout preventer head removal tools and methods. 
       BACKGROUND 
       [0003]    In the early years of oil production it was not uncommon for a blowout on an oil well being drilled to occur. A blowout is an uncontrolled release of oil from an oil well or gas from a gas well. One may think of the classic picture of a gusher at Spindletop, Tex. throwing oil out of the top. Blowouts are both dangerous and wasteful. Blowouts would often push the drill string out of the well and injure or kill workers. 
         [0004]    With the advent of rotary drilling techniques, which use the density of the drilling fluid, or “mud,” to overcome the downhole pressure of a penetrated zone, gushers became less frequent. At times, however, the fluid density was not adequate and a blowout would still occur. In the 1920s, blowout preventers (BOP) were developed to regulate the pressure at or near the wellhead and they soon became standard equipment. In recent times, blowout preventers have entered the news because of the alleged failure of the 300-ton blowout preventer on the Deepwater Horizon well off the coast of Louisiana. Three main manufacturers of blowout preventers today are Hydril, Cameron, and Shaffer. 
         [0005]    In modern drilling operations, drill strings are placed through a blowout preventer stack before running toward the oil and gas reservoir. The drilling fluid (mud) is pumped through the drill string down to the drill bit and then returns up the space (annulus) between the outside of the drill pipe and the casing. When an excessive influx of pressure enters from the reservoir, automated systems or an operator activates the blowout preventer and the blowout preventer seals the annulus and stops the flow of fluids. 
         [0006]    Because blowout preventers are so important to safety and protection of the environment, regulations and practices require that blowout preventers be inspected on a regular basis. For example, after drilling a well, the blowout preventer is typically tested to make sure that there are no leaks. Depending one wear and circumstances, the seals within the blowout preventer are replaced. To replace the seals, the blowout preventer is opened, and in particular the annular BOP head is removed. Conventionally, the studs in the annular head are turned manually using a pipe through the studs on the annular head and with the workers suspended in a basket. The process is more dangerous, difficult, and time consuming than desired. 
       SUMMARY 
       [0007]    According to an illustrative embodiment, a tool for removing a threaded, blowout-preventer head using a rotating device includes a longitudinal shaft having a first end and a second end, a lifting eye member coupled to the first end of the shaft, and a head-mounting member having a first side and a second side. The head-mounting member is coupled to the second end of the longitudinal shaft. The head-mounting member includes a plurality of apertures for receiving a plurality of studs on the threaded, blowout preventer head. The shaft and head-mounting member have a combined longitudinal length that allows a rotating device to be coupled to a portion of the shaft in order to rotate the shaft and remove the blowout preventer head. 
         [0008]    According to another illustrative embodiment, a method for removing a threaded, blowout-preventer head from a blowout preventer includes providing a tool for removing the threaded, blowout-preventer head using a rotating device. The tool includes a longitudinal shaft having a first end and a second end, a lifting eye member coupled to the first end of the shaft, and a head-mounting member having a first side and a second side. The head-mounting member is coupled to the second end of the longitudinal shaft. The head-mounting member includes a plurality of apertures for receiving a plurality of studs on the blowout preventer head. The method further includes positioning the second side of the head-mounting member proximate to a first side of the threaded, blowout-preventer head; bolting the head-mounting member to the threaded, blowout-preventer head; providing a rotating device, wherein the shaft and head-mounting member have a combined longitudinal length that allows the rotating device to be coupled to a portion of the shaft in order to rotate the shaft and remove the blowout preventer head; coupling the rotating device to a portion of the shaft; and using the rotating device to rotate the shaft to cause the threaded, blowout-preventer head to be unscrewed from a mating portion of the blowout preventer. 
         [0009]    According to another illustrative embodiment, a tool for removing a threaded, blowout-preventer head using a rotating device includes: a longitudinal shaft having a first end and a second end, wherein the shaft is at least 8 feet (2.4 meters) long and is less than 25 feet (7.62 meters) long, wherein the shaft is a pipe having an outside diameter greater than four inches (10.2 centimeters) and less than 10 inches (25.4 centimeters) and a wall thickness greater than ½ inch (1.3 inches) and less than three inches (7.6 centimeters); a lifting eye member coupled to the first end of the shaft, wherein the lifting eye member comprises a lifting eye plate coupled to a base plate; a head-mounting member having a first side and a second side, wherein the head-mounting member is coupled to the second end of the longitudinal shaft, wherein the head-mounting member includes a plurality of apertures for receiving a plurality of studs on the blowout preventer head; wherein the shaft and head-mounting member have a combined longitudinal length that allows a rotating device to be coupled to a portion of the shaft in order to rotate the shaft and remove the blowout preventer head; wherein the head-mounting member comprises: a mounting plate having the plurality of apertures and having a first side and a second side, a plurality of gussets having a first edge and a second edge, wherein the second edges of the plurality of gussets are coupled to the first side of the mounting plate, and a torque plate having a first side and a second side, wherein the first edges of the plurality of gussets are coupled to the second side of the torque plate; a first torque arm pivotally coupled to the first side of the head-mounting member, the first torque arm having a first end and a second end; a second torque arm pivotally coupled to the first side of the head-mounting member and spaced approximately 180 degrees from the first torque arm, the second torque arm having a first end and a second end; an anchor bar coupled to a medial portion of the shaft on an exterior, the anchor bar having a first extension with an aperture and as second extension with an aperture; wherein the first end of the first torque arm has an aperture and a first anchor shackle in the aperture, wherein the first send of the second torque arm has an aperture and a second anchor shackle in the aperture; wherein the second end of the first torque arm is coupled to a first hinge that is coupled to the first side of the head-mounting member; wherein the second end of the second torque arm is coupled to a second hinge that is coupled to the first side of the head-mounting member; wherein the anchor bar is positioned and configured such that the aperture in the first extension mates with the first anchor shackle on the first torque arm to hold the first torque arm in a stored position and configured so that the aperture in the second extension mates with the second anchor shackle on the second torque arm to hold the second torque arm in a stored position; wherein a first plurality of apertures is formed proximate the second end of the first torque arm for aligning with a first plurality of apertures formed in the torque plate when the tool is in the torque position; wherein a second plurality of apertures is formed proximate the second end of the second torque arm for aligning with a second plurality of apertures formed in the torque plate when the tool is in the torque position; a first plurality of brace members coupled to the first side of the head-mounting member to form a first torque-arm-receiving channel for receiving a portion of the first torque arm when the tool is in a torque position; and a second plurality of brace members coupled to the first side of the head-mounting member to form a second torque-arm-receiving channel for receiving a portion of the second torque arm when the tool is in a torque position. 
         [0010]    Other features and advantages of the illustrative embodiments will become apparent with reference to the drawings and the detailed description that follow. 
     
    
     
       BRIEF DESCRIPTION 
         [0011]    Illustrative embodiments are described in detail below with reference to the attached drawing figures, which are incorporated by reference herein and wherein: 
           [0012]      FIG. 1  is a schematic, perspective view of an illustrative embodiment of a tool for removing a threaded, blowout-preventer head using a rotating device and showing an illustrative blowout preventer; 
           [0013]      FIG. 2  is a schematic, perspective view of the tool of  FIG. 1  shown in a torque position; 
           [0014]      FIG. 3  is a schematic, exploded, perspective view of a portion of an illustrative embodiment of a tool for removing a threaded, blowout-preventer head using a rotating device; 
           [0015]      FIG. 4  is a schematic, exploded, perspective view of a portion of an illustrative embodiment of a tool for removing a threaded, blowout-preventer head using a rotating device showing an illustrative embodiment of a head-mounting member; 
           [0016]      FIG. 5  is a schematic, perspective view of a portion of an illustrative embodiment of a tool for removing a threaded, blowout-preventer head using a rotating device showing an illustrative embodiment of a head-mounting member; and 
           [0017]      FIG. 6  is a schematic, perspective view of a portion of an illustrative embodiment of a tool for removing a threaded, blowout-preventer head using a rotating device showing an illustrative embodiment of a head-mounting member. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
         [0019]    Referring now to the drawings and initially to  FIG. 1 , an illustrative embodiment of a tool  10  for removing a threaded, blowout-preventer head  12 , or annular head, of a blowout preventer  14  using a rotating device on a rig, e.g., a top drive, kelly, or rotary table is presented. The tool  10  allows the threaded, blowout-preventer head  12  to be removed from the blowout preventer  14  quickly and easily. 
         [0020]    In a typical oil rig, the casing extends from the wellhead into the ground and the drill string  16  with a drill bit is placed through the casing and into the ground. Usually on top of the wellhead is at least one blowout preventer  14  as previously discussed. The drilling platform is over that with the derrick extending vertically to facilitate the addition of the drill string  16 . 
         [0021]    There are a number of manufacturers of blowout preventers. For illustration purposes, a HYDRIL blowout preventer, e.g., a GK or GX Series blowout preventer, is presented. It should be understood that the tool  10  could be used with any blowout preventer  14  having a threaded, blowout preventer head  12  that is removed for gaining access to an interior portion and some BOP without threads. The blowout preventer  14  has a body  18 . In  FIG. 1 , the tool  10  is shown aligned with a first side  20  of the threaded, blowout preventer head  12 . A plurality of studs  22  extends from the threaded, blowout preventer head  12 . In  FIG. 1 , four studs  22  are shown but more or less may involved at the time the threaded, blowout preventer head  12  is to be removed. 
         [0022]    The tool  10  includes a longitudinal shaft  24  having a first end  26  and a second end  28 . The longitudinal shaft  24  may be a pipe shaft or could be a solid shaft. The shaft  24  may take any appropriate size, but in one embodiment is between five feet (1.52 meters) and 20 feet (6.1 meters) in length. A lifting eye member  30  is coupled, e.g., welded or drilled and tapped with a bolt, to the first end  26  of the shaft  24 . The lifting eye member  30  may be any device to facilitate lifting of the tool  10  using an air hoist line, main hoist, elevator, or other lifting device. For example, as shown in  FIG. 3 , the lifting eye member  30  may be formed by coupling a base plate  32  to the first end  26  of the shaft  24  and perpendicularly coupling a lifting eye plate  34  to the base plate  32 . The lifting eye plate  34  includes an aperture  36  for receiving a lifting hook or other device. The tool  10  also includes a head-mounting member  38 . 
         [0023]    The head-mounting member  38  has a first side  40  and a second side  42 . The first side  40  of the head-mounting member  38  is coupled to the second end  28  of the longitudinal shaft  24  in some embodiments ( FIG. 5 ) or as shown in  FIGS. 1-2 , the shaft  24  may extend into the head-mounting member  38  and be coupled to a mounting plate  46 . The head-mounting member  38  includes a plurality of apertures  44  for receiving the plurality of studs  22  on the threaded, blowout preventer head  12 . The apertures  44  may have the same spacing and be the same number as possible studs  22  on the threaded, blowout preventer head  12  or a lesser number in some embodiments. The head-mounting member  38  may take numerous configurations and three illustrative embodiments are shown in  FIGS. 4 ,  5 , and  6  as will be described. 
         [0024]    Referring now primarily to  FIGS. 1-2  and  4 , one illustrative embodiment of the head-mounting member  38  is now presented. In this embodiment, the head-mounting member  38  includes a mounting plate  46  having the plurality of apertures  48  and having a first side  50  and a second side  52 . The head-mounting member  38  also includes a plurality of gussets  54  having a first edge  56  and a second edge  58 . The second edges  58  of the plurality of gussets  54  are coupled to the first side  50  of the mounting plate  46 . The head-mounting member  38  also includes a torque plate  60  having a first side  62  and a second side  64 . The first edges  56  of the plurality of gussets  54  are coupled to the second side  64  of the torque plate  60 . The shaft  24  extends through a central aperture  65  in the torque plate  60  and is coupled to the first side  50  of the mounting plate  46 . In one illustrative embodiment, the mounting plate  46  is separated from the torque plate  60  by at least 10 inches (25.4 centimeters) and less than 30 inches (76.2 centimeters) and may take any dimension there between, e.g., 16 inches. 
         [0025]    Referring now primarily to  FIG. 5 , another illustrative embodiment of the head-mounting member  38  is presented. The head-mounting member  38  includes a solid disc member  62  having a first side  64  and a second side  66  and a plurality of apertures  68  extending through the solid disc member  62 . The second end  28  of the shaft  24  is coupled to the first side  64  of the solid disc member  62 . 
         [0026]    Referring now primarily to  FIG. 6 , another illustrative embodiment of the head-mounting member  38  is presented. The head-mounting member  38  includes a base mounting plate  70  having a first side  72 , a second side  74 , and apertures  75 . The second end  28  of the shaft  24  is welded to the first side  72  of the base mounting plate  70 . A plurality of triangular gussets  76  are coupled to the base mounting plate  70  and to an exterior of the shaft  24 . The gussets  76  could take other shapes, such as, an arcuate member. 
         [0027]    Regardless of the specific embodiment of the head-mounting member  38 , the shaft  24  and head-mounting member  38  have a combined longitudinal length that allows a rotating device, e.g., top drive, kelly, or rotary table, to be coupled to a portion of the shaft  24  in order to rotate the shaft  24  and remove the blowout preventer head  12 . 
         [0028]    Referring again to  FIGS. 1-2 , one or more torque arms, e.g., a first torque arm  78  and a second torque arm  84 , may be pivotally coupled to the head-mounting member  38 . In this embodiment, the first torque arm  78  is spaced approximately 180 degrees away from the second torque arm  84 . More arms might be used and spaced equally or in patterns. The first torque arm  78  has a first end  80  and a second end  82 , and the second torque arm  84  has first end  86  and a second end  88 . The second end  82  of the first torque arm  78  is pivotally coupled to the head-mounting member  38  by a first hinge  90 . Likewise, the second end  88  of the second torque arm  84  is pivotally coupled to the head-mounting member  38  by a second hinge  92 . 
         [0029]    For the embodiment of  FIGS. 1-2 , a plurality of apertures  94  are formed proximate the second end  82  of the first torque arm  78  and are aligned with a plurality of apertures  96  in the torque plate  60 . When in the torque position, the first torque arm  78  is pivoted to be substantially perpendicular to the shaft  24  as shown in  FIG. 2  and bolts (not explicitly shown) may be placed through the apertures  94 ,  96  and secured. Likewise, a plurality of apertures  98  are formed proximate the second end  88  of the second torque arm  84  and are aligned with a plurality of apertures  100  in the torque plate  60 . When in the torque position, the second torque arm  84  is pivoted to be substantially perpendicular to the shaft  24  as shown in  FIG. 2  and bolts (not explicitly shown) may be placed through the apertures  98 ,  100  and secured. Operators may then apply a turning force on the torque arms  78 ,  84  to provide additional torque on the threaded, blowout preventer head  12  to break the initial engagement of the threads. A come along winch may also be attached to the torque arm to provide additional torque still. 
         [0030]    The tool  10  may include one or more devices for holding the torque arms  78 ,  84  in a stored position when the tool  10  is being positioned or is not being used. For example, the first end  80  of the first torque arm  78  may be formed with an aperture  102  and a first anchor shackle  104  may be placed in the aperture  102 . Then, when in the stored position, the first anchor shackle  104  may be used in conjunction with an anchor bar  106  (or anchor plate) on a medial portion  108  of the shaft  24  to secure the first torque arm  78  in a stored position as shown in  FIG. 1 . The anchor plate bar  106  may be formed with a first extension  109  having a first aperture  110  for receiving the first anchor shackle  104 . Likewise, the second torque arm  84  may be formed with an aperture  112  and a second anchor shackle  114  disposed in part through the aperture  112 . The second anchor shackle  114  is sized and configured to releasably couple to the anchor bar  106 . For example, the second anchor shackle  114  may be coupled through an aperture  116  on a second extension  118  of the anchor bar  106 . As shown best in  FIG. 3 , the anchor bar  106  may be formed with a central aperture  120  that is slide on the shaft  24  before being coupled, e.g., welded. 
         [0031]    Referring to  FIGS. 1-2  and  4 , additional support for one or more torque arms may be supplied by forming a torque-arm-receiving channel for each torque arm. For example, a first plurality of brace members  122  may form a first torque-arm-receiving channel  124  for receiving a portion of the at least one torque arm when the tool  10  is in a torque position ( FIG. 2 ). The first plurality of brace members  122  are coupled to the first side  40  of the head-mounting member  38 . Thus, when the first torque arm  78  is in the torque position, the lateral edges of the first torque arm  78  substantially abut or otherwise engage a portion of the first plurality of brace members  122  and provide additional support for transferring of forces. Likewise, a second plurality of brace members  128  is coupled to the first side of the head-mounting member  38  to form a second torque-arm-receiving channel  130 . 
         [0032]    In operation according to one embodiment, an upper stack (not shown) is removed from the top of the blowout preventer  14  to expose the first side  20  of the threaded, blowout preventer head  12 . One of the tools  10  for removing the threaded, blowout-preventer head  12  using a rotating device previously discussed is provided. The tool  10  is raised to the driller floor by attaching an air hoist line to the lifting eye member  30  and raising the tool  10 . Once the tool  10  has been lifted to the driller floor, the air hoist line may be removed and then an elevator line or main hoist line may be attached to the tool  10  on the shaft  24  or lifting eye member  30 . 
         [0033]    The tool  10  is then moved through the turn table of the rig and positioned such that the second side  42  of the head-mounting member  38  is proximate the first side  20  of the threaded, blowout preventer head  12 . The tool  10  is then bolted to the threaded, blowout preventer head  12  using studs  22 . Then the rotating device, e.g., kelly or top drive, may be coupled to a portion of the shaft  24  to provide a rotating force to the tool  10 . Supplemental torque may be provided by using tongs and a winch line or automatic rough neck (e.g., ST-80 Iron Roughneck from National Oilwell Varco of Houston, Tex.). The turning motion loosens the threaded, blowout preventer head  12  and allows the threaded, blowout preventer head  12  to be unscrewed and removed. 
         [0034]    If the threaded, blowout preventer head  12  is too difficult to remove as describe, the initial turn of the threaded, blowout preventer head  12  may be accomplished with additional torque. In such a case, one or more torque arms  78 ,  84  may be rotated into the torque position, bolted down using apertures  94 ,  98  in the torque arms  94 ,  98  and apertures  96 ,  100  in the torque plate  60 , and then force may be applied to provide additional torque. The additional force applied to the torque arms  78 ,  84  may be applied directly by human operators or may be applied using a pulling device, e.g., a come along winch, air or electric tugger hoist, air or electric winch, or other pulling device. As an alternative, a separate torque arm may be simply placed over apertures  96  or  100  and bolted into to position before having a force applied. As another alternative, a cable may be bolted to one of the apertures  44  not be occupied by a stud  22  or through an aperture in the torque plate (e.g., aperture  100 ) and then a force applied to the cable by a pulling device. 
         [0035]    Once the threaded, blowout preventer head  12  is unscrewed from the mating threads of the blowout preventer  14 , the threaded, blowout preventer head  12  may be lifted through the turn table of the rig and placed on the driller floor. The threaded, blowout preventer head  12  may remain attached to the tool  10  until the seals are replaced or other maintenance on the blowout preventer is complete. The threaded, blowout preventer head  12  may be set on the driller floor. After this, the tool  10  is used to lower the threaded, blowout preventer head  12  through the turn table and back onto the blowout preventer body  18 . The rotating device may then be used to rotate the threaded, blowout preventer head  12  back onto the mating threads of the blowout preventer  14 . The tool  10  is then unbolted and removed. The stack can then be attached to the threaded, blowout preventer head  12  and any lines attached. 
         [0036]    Although the present invention and its advantages have been disclosed in the context of certain illustrative, non-limiting embodiments, it should be understood that various changes, substitutions, permutations, and alterations can be made without departing from the scope of the invention as defined by the appended claims. It will be appreciated that any feature that is described in a connection to any one embodiment may also be applicable to any other embodiment.