Patent Publication Number: US-2007114069-A1

Title: Apparatus for positioning and stabbing pipe in a drilling rig derrick

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
      NONE  
     STATEMENTS AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT  
      NONE  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to an apparatus for positioning and stabbing tubular goods, including large diameter pipe such as casing, within a drilling rig derrick. More particularly, the present invention pertains to an apparatus which can be mounted within a drilling rig derrick, and which can grip a section of pipe, such as large diameter casing, suspended within said derrick. More particularly still, the present invention pertains to a remotely operated apparatus which can grip a section of pipe suspended within a drilling rig derrick and align such pipe so that threads at the lower end thereof can be joined with mating threads of a section of pipe situated therebelow.  
      2. Brief Description of the Prior Art  
      Standard rotary drilling rigs are typically comprised of a supportive rig floor, a roughly vertical derrick extending above said rig floor, and a traveling block which can be raised and lowered within said derrick. Such rig equipment is often used to insert and remove tubular goods, such as pipe, from a wellbore which is being drilled or serviced.  
      Drill bits and other equipment used in connection with the drilling and/or servicing of wells are typically conveyed into and out of such wells on tubular pipe known as drill pipe or “drill string”. At a point that a well has been drilled to a desired depth, large diameter pipe called casing is often installed in said well and cemented in place. Such casing, which provides structural integrity to the wellbore and helps keep geologic formations isolated from one another, is also installed in wells using the above described drilling rig equipment.  
      Casing, drill pipe or other similar tubular goods are typically installed in wells in a number of different sections of roughly equal length. These sections, often called “joints,” are typically screwed together or otherwise joined end-to-end at the earth&#39;s surface in order to form a roughly continuous “string” of pipe. As the bottom or distal end of the pipe string penetrates further into a well, additional joints of pipe are added is to the ever lengthening pipe string in the rig derrick. Conversely, when pipe is being removed from a wellbore, the pipe string is pulled from the well and joints are unscrewed in the rig derrick, one or more at a time, until all of the pipe has been retrieved from said well.  
      The process of inserting a string of pipe in a well is typically commenced by lowering a first section of pipe into a wellbore at the rig floor, and suspending said section of pipe in place using a set of “lower slips.” In this position, the uppermost end of said first section of pipe is generally situated a few feet above the rig floor. Thereafter, a second section of pipe is lifted within the drilling rig derrick and suspended vertically in said derrick from the rig&#39;s traveling block. This second section of pipe is then positioned in linear alignment above the first section of pipe which was previously run into the well. The lower end of said second section is then connected to the upper end of said first section. Once joined, the two sections of pipe are lowered further into the well and hung in place using lower slips. This process is repeated until the desired length of pipe is run into the well.  
      In many cases, individual sections of pipe are joined together using threaded connections. In such instances, the upper end of one section of pipe has threads which engage with mating threads on the lower end of an adjacent section of pipe. It is the custom of the oil and gas industry to insert sections of pipe into a wellbore so that male or “pin” end threaded connections face downward, while female or “box” end connections face upward. Thus, when individual joints of pipe are added to a string of pipe in a well in the manner described above, the pin end of the upper joint of pipe (which is suspended within a derrick) is typically “stabbed” into the box end of the lower joint (which is suspended in the well bore). The upper joint is then rotated so that the mating threads of the two joints join together.  
      Numerous devices have been developed to assist in the alignment and interconnection of joints of elongated pipe and other tubular goods used in the drilling and completion of oil and gas wells. Many of these devices employ means for gripping a joint of pipe while it is suspended within a derrick. Force is then applied to said suspended pipe joint until it is oriented in linear alignment with one or more joints of pipe which have already been inserted in such wellbore.  
      Because drill pipe usually has a smaller diameter than casing, it is often much lighter on a per-foot basis than casing. As a result, a suspended section of drill pipe can generally be manually aligned within a derrick by roughnecks and/or other rig workers. Perhaps more significantly, drill pipe threads are typically very coarse compared to casing threads. Accordingly, drill pipe threads are relatively difficult to misalign when joints of drill pipe are brought into end-to-end abutting relationship for threaded interconnection.  
      By contrast, because casing is generally much heavier than drill pipe and other similar tubular goods, it is often difficult, if not impossible, for rig workers to manually position such casing within a derrick. Furthermore, casing joints typically employ connections having relatively fine threads. As a result, it is critical that joints of casing which are to be threadably connected must be in close linear alignment with one another. If not, the threaded pin end of one casing joint can become cross threaded with the box end of the next adjacent casing joint. Such cross-threading can occur even when there is very slight misalignment between two adjacent joints of casing.  
      Thus, it is generally advantageous to provide means for positioning heavy tubular goods, such as casing, while it is suspended within a drilling rig derrick. Moreover, such positioning means must promote relatively precise alignment of adjacent joints of casing to ensure proper threaded connection of such casing.  
      Thus, there is a need for a pipe stabbing apparatus which can be mounted within a drilling rig derrick, and which can be used to grip and position a section of pipe suspended within such derrick. Specifically, there is a need for a pipe stabbing apparatus having a versatile range of motion in multiple planes of movement. There is further a need for a pipe stabbing apparatus capable of gripping different sizes of pipe having a wide range of different diameters, without having to shut down operations in order to manually adjust or reconfigure such stabbing apparatus.  
     BRIEF DESCRIPTION OF THE PRESENT INVENTION  
      The present invention is a pipe stabbing apparatus which can be easily lifted into a drilling rig derrick and secured to one or more members of such derrick. The apparatus of the present invention is fully automated, and can be remotely controlled from a control panel that can be positioned at virtually any desired location on a rig, including the rig floor. By virtue of such adjustable remote control panel, an operator of the apparatus can position himself so as to view a pipe section which is engaged by the apparatus. Using such direct visual input, an operator can control the movement of the apparatus in order to manipulate the positioning of a first joint of pipe which is suspended in a derrick as it is brought into linear alignment with a second section of pipe suspended within a wellbore.  
      The present invention is significantly less bulky than other known devices utilized for this purpose. The apparatus of the present invention employs a jointed boom which can be mounted at virtually any location within a derrick, and thus affords little interference with other operations taking place within said derrick. The apparatus is movable in virtually every plane of motion, and the boom can be easily extended or retracted in order to grip and position a section of pipe suspended from a traveling block in a derrick. The present invention can even grip a suspended section of pipe below the vertical position at which said boom is mounted within said derrick. Moreover, the apparatus of the present invention is especially well adapted for gripping many different sizes of pipe, including very large diameter casing, without requiring operations to cease for adjustment or reconfiguration of the apparatus.  
      The pipe stabbing apparatus of the present invention includes a jointed, extensible boom. One end of said boom can be quickly secured to a structural member or cross beam of a drilling rig derrick using a bracket assembly or other similar mechanism. Further, the end of the boom which is secured to the derrick can pivot about both vertical and horizontal axes. A pipe gripper is attached to the opposite (free) end of said extensible boom.  
      A primary remote control panel serves as the distribution point or manifold from which hydraulic fluid can be directed to one or more hydraulic piston and cylinder assemblies used to move the boom in several different planes of movement, and to open and/or close said pipe gripper. Said primary remote control panel includes a plurality of solenoid-type valves which can be selectively opened in order to direct such hydraulic fluid and, ultimately, to control movement of the extensible boom and pipe gripper. A secondary remote control panel is also included, in close proximity to said extensible boom, to facilitate manipulation of said boom during the mounting process.  
      The primary remote control panel includes lines which can extend to the derrick floor or other desired location on the rig. Certain of these lines are hydraulic lines which function, respectively, to deliver power fluid from a pump to the hydraulic cylinders of the extensible boom mounted in the derrick, and to return such hydraulic fluid to a reservoir. One or more power source cables also extend from the derrick-mounted boom to the electrically operated valves. Additionally, a control cable runs to the primary remote control panel which is positioned at a desired location on the rig which, in most cases, is on the rig floor.  
      A secondary control panel is located in relatively close proximity with the jointed extensible boom of the present invention. The secondary control panel is particularly useful when the casing stabber of the present invention is being mounted within a drilling rig derrick, or when said casing stabber is being removed from said derrick. Said jointed extensible boom can be extended and/or retracted as desired in order to facilitate handling and mounting/removal of said casing stabber.  
      The jointed, extensible boom can be hydraulically actuated to extend and retract as desired. The end of the boom which is mounted to the derrick can pivot about vertical and horizontal axes, thereby permitting both side-to-side as well as up-and-down movement. A pipe gripper is mounted to the outer or “free” end of said boom. The pipe gripper is comprised of a pair of opposing arcuate jaws that are pivotally supported on the free end of the boom and are hydraulically actuated for opening or closing. Such jaws can be engaged around many different sizes of pipe, and do not impair or restrict the ability of a gripped pipe joint to be rotated or turned about its longitudinal axis. Such opposing arcuate jaws can also be pivoted about a horizontal axis.  
      An important object of the present invention is to provide a pipe stabbing apparatus which can be easily taken apart to facilitate transport, storage and operative mounting of the entire apparatus at a selected position within a drilling rig derrick and above the rig floor.  
      A further object of the invention is to provide a pipe stabbing apparatus which includes an extensible boom, as well as a pipe gripping assembly at one end, which is hydraulically movable in several planes of motion.  
      A further object of the invention is to provide a pipe stabbing apparatus which can grip and steer tubular goods, including large diameter pipe such as casing, and which allows such pipe to be spun or rotated about its longitudinal axis, even while such pipe is engaged by said pipe stabbing apparatus.  
      A further object of the present invention is to provide a pipe stabbing apparatus utilizing pipe gripping jaws which can permit many different sizes of pipe to be gripped and moved without the need to adjust or re-size such pipe gripping jaws.  
      Additional objects and advantages of the invention will become apparent as the following detailed description of the invention is read in conjunction with the accompanying drawings which illustrate a preferred embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view depicting the pipe stabbing apparatus of the present invention mounted within the derrick of a drilling rig and used for gripping, engaging and aligning a section of casing suspended from a traveling block within said derrick.  
       FIG. 2  is a perspective view of the pipe stabbing apparatus of the present invention gripping a section of large diameter casing.  
       FIG. 3  is a perspective view of the opposing arcuate pipe gripping jaws of the present invention in the open position.  
       FIG. 4  is a perspective view of the opposing arcuate pipe gripping jaws of the present invention in the closed position.  
       FIG. 5  is a systemic view of the pipe stabbing apparatus of the present invention wherein the pipe gripping jaws are gripping a section of large diameter casing.  
       FIG. 6  is a perspective view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing.  
       FIG. 7  is a side view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing.  
       FIG. 8  depicts a side view of an alternative embodiment of the pipe stabbing apparatus of the present invention. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION  
      Referring initially to  FIG. 1  of the drawings, drilling rig  10  is depicted during operations for the installation of casing into a well. Vertically extending derrick  11  and rig floor  12  are supported on drilling platform  13 . Rotary  14 , which is positioned on rig floor  12  at the surface of well  15 , supports, by means of suitable lower slips  16 , an elongated section of casing  17 . The upper portion of casing section  17  protrudes out of rotary  14  and is situated above rig floor  12 , while the remainder of casing section  17  projects downwardly from the rig floor and, ultimately, into the well  15  being drilled or serviced.  
      When installing casing into well  15 , it is necessary to serially interconnect multiple sections of casing at a point of joinder a short distance above rig floor  12 . The process is commenced by installing a first section of casing  17  into well  15 , and hanging or suspending same in place using lower slips  16 . As succeeding sections of casing are added to the casing string being installed, the entire string is lowered into well  15  and suspended in place using lower slips  16 . This process is repeated until a desired length of casing is installed into wellbore  15 .  
      Still referring to  FIG. 1 , casing section  18  is shown suspended from upper slips  19  attached to traveling block  20 . Traveling block  20  is capable of vertical movement within derrick  11 . Once casing section  18  is placed in linear alignment with casing section  17 , roughneck  21  can turn or rotate said casing section  18 , thereby causing mating threaded connections at the uppermost end of casing section  17  and the lowermost end of casing section  18  to interconnect.  
      The present invention is primarily used to guide or position a suspended first section of large diameter pipe into linear alignment with a second section of pipe in order to facilitate threaded interconnection of said first and second sections of pipe. Referring to  FIG. 1 , the pipe stabbing apparatus of the present invention, denoted generally as  100 , is used to move suspended casing section  18  so as to more precisely align said suspended casing section  18 , and more particularly the lowermost threaded end thereof, with the uppermost threaded end of casing section  17 , which is suspended in wellbore  15 . By aligning said casing sections  17  and  18 , said pipe sections can be threadably connected with less chance of cross-threading.  
      Still referring to  FIG. 1 , pipe stabbing apparatus  100  of the present invention is mounted within vertical drilling rig derrick  11 . The specific placement of pipe stabbing apparatus  100  within derrick  11  is generally dictated by the layout of the particular drilling rig and derrick on which it is employed. However, said pipe stabbing apparatus  100  is generally mounted at a vertical level which permits maximum functionality and range of motion with respect to sections of pipe suspended within derrick  11 , such as casing section  18 . Further, while pipe stabbing apparatus  100  can be mounted on any side of derrick  11 , said pipe stabbing apparatus  100  is typically positioned so as to permit maximum visibility for personnel located on rig floor  12 , and to avoid interference with operation of other equipment within derrick  11 .  
       FIG. 2  depicts a side perspective view of pipe stabbing apparatus  100  of the present invention. Said pipe stabbing apparatus  100  is mounted to derrick  11  using brackets or similar devices so that said pipe stabbing apparatus projects generally in the direction of well  15  as illustrated in  FIG. 1 . Depending on the configuration of the particular drilling rig being used, the optimum position for mounting of pipe stabbing apparatus  100  is frequently in direct lateral alignment with the centerline of casing section  18 , and near the mid-point of one side of derrick  11 .  
      Still referring to  FIG. 2 , pipe stabbing apparatus  100  includes jointed, articulating boom  110 . Jointed articulating boom  110  is comprised of boom base member  111  and boom arm member  112 , which are pivotably joined with one another using boom pivot joint  113 . In the preferred embodiment, said articulating boom is comprised of two structural members, with a single joint therebetween. However, it can be envisioned that other combinations of structural members and pivoting joints could be employed to yield similar results and/or functionality. Also in the preferred embodiment, boom base member  111  includes obtuse angle  111   a,  while arm member  112  is substantially straight.  
      Jointed articulating boom  110  is attached to base assembly  114 , which is used to mount pipe stabbing apparatus  100  to structural members of derrick  11 . Although mounting of pipe stabbing apparatus  100  within derrick  11  can be accomplished any number of ways, in the preferred embodiment base assembly is attached to vertical runners  114   a  and  114   b.  Said vertical runners  114   a  and  114   b  are in turn bracketed to horizontal cross members or other structural components of rig derrick  11 .  
      Boom base member  111  is attached to eccentric base plate  119 , which is in turn pivotably anchored to vertical base shaft  115 . Eccentric base plate  119  rotates about pivot pin  116 , thereby permitting boom base member  111  (and thus all of jointed articulating boom  110 ) to rotate about a vertical axis passing through vertical base shaft  115  and pivot pin  116 . In the preferred embodiment of the invention, the range of motion of said eccentric base plate  119  and jointed articulating boom is roughly 180 degrees.  
      Rotation of boom base member  110  about pivot pin  116  is powered by hydraulic cylinder  117 . One end of hydraulic cylinder  117  is anchored to base assembly  114  with anchor means  118 , such as a suitable pin and bracket. Hydraulic cylinder  117  further includes piston rod  120  (substantially obscured from view in  FIG. 2 ). One end of said piston rod  120  is anchored to eccentric plate  119 . As piston rod  120  of hydraulic cylinder  117  is extended and retracted, eccentric plate  119  is made to rotate about pivot pin  116 , which in turn causes boom base member  111  (and, ultimately, all of jointed articulating boom  110 ) to rotate about said pivot pin  116 .  
      Jointed articulating boom  110  extends and retracts by cooperative motion between boom base member  111  and boom arm member  112 . Boom base member  111  is pivotably mounted to eccentric plate  119  using horizontal pivot pin  121 . As a result, boom base member  111  can pivot about a horizontal axis passing through said horizontal pivot pin  121 , thereby permitting boom base member  111  to tilt forward. As such, when mounted within derrick  11 , jointed articulating boom can tilt forward in the general direction of well  15 .  
      The movement of boom base member  111  about the horizontal axis passing through pivot pin  121  is powered by hydraulic cylinder  122 . One end of hydraulic cylinder  122  is anchored to vertical base shaft  115 . Anchor bracket  123  is pinned to anchor plate  124  by means of a suitable anchor pin  125 . Hydraulic cylinder  122  further includes piston rod  126 , which can be extended and retracted with respect to hydraulic cylinder  122 . The outer end of piston rod  126  is anchored to clevis plate  127  using clevis bracket  128  and clevis pin  129 . The movement of piston rod  126  is controlled from a remote control panel subassembly, hereinafter explained, through hydraulic lines or conduits to said hydraulic cylinder and to other hydraulic cylinders used in the casing stabbing apparatus of the invention, and hereinafter described.  
      Similarly, movement of boom arm member  112  relative to boom base member  111  is powered by hydraulic cylinder  130 . Hydraulic cylinder  130  is anchored at one end to boom base member  111 ; anchor bracket  131  is pinned to anchor plate  132  by means of suitable anchor pin  133 . Hydraulic cylinder  130  further includes piston rod  134 . One end of piston rod  134  is anchored to boom arm member  112  with anchor pin  135 . Piston rod  134  can be extended and retracted with respect to hydraulic cylinder  130 , thereby permitting boom arm member  112  to swing about a horizontal axis passing through boom pivot joint  113 .  
      Pipe gripper assembly  200  is mounted at the outer extent of boom arm member  112 . Pipe gripper assembly  200  includes opposing arcuate jaws  201   a  and  201   b.  Pipe gripper assembly  200  is mounted to mounting plate  208 , which is in turn pivotably mounted to the end of boom arm member  112  with pivot pin  202 , thereby permitting said pipe gripper assembly  200  to pivot about a horizontal axis passing through said pivot pin  202 .  
      Pivoting of said pipe gripper assembly  200  about said horizontal axis passing through pivot pin  202  is powered by hydraulic cylinder  203 . One end of hydraulic cylinder  203  is anchored to boom arm member  112  using anchor bracket  204  and anchor pin  205 . Hydraulic cylinder  203  further includes piston rod  206 . The outer end of piston rod  206  is pinned to mounting plate  208  using anchor pin  207 . As piston rod  206  of hydraulic cylinder  203  extends and retracts, pipe gripper assembly  200  can swivel about pivot pin  202 , and can tilt up or down about a horizontal axis passing through pivot pin  202 , as desired.  
      Derrick control panel subassembly  300  includes a bank of valves which are electrically opened and closed using controls  301 . Further, said valves are shiftable to provide hydraulic power fluid to a selected one or more of the hydraulic cylinders used to power jointed articulating boom  110  and pipe gripper assembly  200  as may be required during the operation of the apparatus for stabbing and positioning a section of casing. Derrick control panel subassembly  300  is in close proximity to jointed articulating boom  110 , and is used primarily to manipulate and/or position jointed articulating boom  110  while said assembly is being mounted to, or removed from, derrick  11 .  
      Hydraulic power fluid supply conduits  136  extend from one end of each of the valves downwardly to the drilling platform and are there connected to a suitable hydraulic pump (not shown in  FIG. 2 ) for the purpose of supplying hydraulic power fluid necessary to operate the several hydraulic cylinder and piston assemblies hereinbefore described. Return conduits  137  also project from each of the valves to the drilling platform to allow exhausted hydraulic fluid to return to a reservoir or sump in the course of recirculation in a conventional fashion.  
      In its standard configuration, a remote control panel subassembly is used to control the movement of jointed articulating boom  110  and pipe gripper assembly  200 . Referring to  FIG. 1 , said remote control panel subassembly  400  is depicted as being positioned on rig floor  12 . Remote control panel  400  includes a bank of electrically actuated valves and valve controls  401  similar to derrick control panel subassembly  300 . Hydraulic power fluid supply conduits  136  and  137  extend out of derrick  11  to pump  402 . Operator  403  operates pipe stabbing apparatus  100 .  
      In order to shift valves controlled by valve controls  401 , electrical solenoids are included in remote control panel subassembly  400 , and are actuated by power signals delivered via conductors extended through a control cable  404  which extends from the drilling platform upwardly to the remote control panel subassembly  400 . Said control cable can be plugged into remote control panel subassembly  400  using a suitable jack.  
       FIG. 3  depicts a perspective view of pipe gripper assembly  200  of the present invention in the substantially open position. Pipe gripper  200  is comprised of opposing arcuate jaws  201   a  and  201   b.  Said opposing arcuate jaws  201   a  and  201   b  are pivotably attached to back member  210  using pivot pins  211   a  and  211   b,  and can swing to permit opening and closing of pipe gripper assembly  200 . In the preferred embodiment, opposing arcuate jaws  201   a  and  201   b  operate in synchronized fashion, such that said opposing arcuate jaws open and close together.  
      Hydraulic cylinder  212  powers the synchronized opening and closing of opposing arcuate jaws  201   a  and  201   b.  Hydraulic cylinder  212  has piston rod  213 , which can be extended and retracted. One end of hydraulic cylinder  212  is anchored to extension fingers  214  using anchor bolt  215 . Similarly, the outer end of piston rod  213  is anchored to extension fingers  216  using anchor bolt  217 . By actuating hydraulic cylinder  212 , and thereby extending or retracting piston rod  213 , opposing arcuate jaws  201   a  and  201   b  can pivot about pivot pins  211   a  and  211   b,  respectively. Mounting bracket  218  is attached to back member  210 , and facilitates mounting of pipe gripper assembly  200  to mounting plate  208  (not shown in  FIG. 3 ).  
       FIG. 4  depicts a perspective view of pipe gripper assembly  200  in a substantially closed position. Opposing arcuate jaws  201   a  and  201   b  are depicted as gripping a section of cylindrical pipe, such as a joint of large diameter casing, around the outer peripheral surface of said pipe. For purposes of illustration, said cylindrical pipe could be identical to casing section  18 . As piston rod  213  extends relative to hydraulic cylinder  212 , opposing arcuate jaws  201   a  and  201   b  close together in synchronized manner and grip around the outer peripheral surface of casing section  18 .  
       FIG. 5  depicts a systemic view of the pipe stabbing apparatus  100  of the present invention. Pipe stabbing apparatus  100  includes jointed articulating boom  110 ; said boom is comprised of boom base member  111  and boom arm member  112 , which are pivotably joined with boom pivot joint  113 . In the preferred embodiment, said articulating boom is comprised of two structural members, with a single joint between said two structural members. Also in the preferred embodiment, boom base member is formed with obtuse angle  11  la, while arm member  112  is substantially straight.  
      Boom base member  111  is pivotably attached to eccentric base plate  119 , which is in turn pivotably anchored to vertical base shaft  115 . Eccentric base plate  119  pivots about pivot pin  116 , thereby permitting boom base member  111 , and ultimately all of jointed articulating boom  110 , to rotate about a vertical axis passing through said vertical base shaft  115  and pivot pin  116 .  
      Rotation of boom base member  110  about pivot pin  116  is powered by hydraulic cylinder  117 . One end of hydraulic cylinder  117  is anchored to mounting assembly  114  with anchor means  118 , such as a suitable pin. Hydraulic cylinder  117  further includes piston rod  120 ; the outer end of piston rod  120  is in turn pinned to eccentric plate  119 . As piston rod  120  of hydraulic cylinder  117  is extended and retracted, eccentric plate  119  rotates about pivot pin  116  which in turn causes boom base member  111  (and, ultimately, all of jointed articulating boom  110 ) to rotate about a vertical axis passing through and parallel to said pivot pin  116 .  
      Jointed articulating boom  110  extends and retracts by cooperative motion between boom base member  111  and boom arm member  112 . Boom base member  111  is pivotably mounted to eccentric plate  119  using pivot pin  121 . As a result, boom base member  111  can pivot about a horizontal axis passing through said pivot pin  121 , thereby permitting boom base member  111  to tilt or lean forward and backward into an upright position.  
      Tilting of boom base member  111  is powered by hydraulic cylinder  122 . Hydraulic cylinder  122  is anchored to vertical base shaft  115 . Anchor bracket  123  is pinned to anchor plate  124  by means of a suitable anchor pin  125 . Hydraulic cylinder  122  further includes piston rod  126 , which can be extended and retracted with respect to hydraulic cylinder  122 . Piston rod  126  is anchored to clevis plate  127  using clevis bracket  128  and clevis pin  129 .  
      Similarly, movement of boom arm member  112  relative to boom base member  111  is powered by hydraulic cylinder  130 . Hydraulic cylinder  130  is anchored at one end to boom base member  111 . Anchor bracket  131  is pinned to anchor plate  132  by means of suitable anchor pin  133 . Hydraulic cylinder  130  further includes piston rod  134 , which is anchored to boom arm member  112  with anchor pin  135 . Piston rod  134  can be extended and retracted with respect to hydraulic cylinder  130 , thereby permitting boom arm member  112  to swing by pivoting about boom pivot joint  113 .  
      Pipe gripper  200  is mounted at the outer extent of boom arm member  112 . Pipe gripper  200  is comprised of opposing arcuate jaws  201   a  and  201   b.  Pipe gripper  200  is pivotably mounted to the end of boom arm member  112  with pivot pin  202 , thereby permitting said pipe gripper to pivot about a horizontal axis passing through said pivot pin  202 .  
      Pipe gripper  200  can pivot about said horizontal axis passing through pivot pin  202 , and is powered by hydraulic cylinder  203 . One end of hydraulic cylinder  203  is anchored to boom arm member  112  with anchor bracket  204  and anchor pin  205 . Hydraulic cylinder  203  further includes piston rod  206 , which is in turn pinned to mounting plate  208  using anchor pin  207 . As piston rod  206  of hydraulic cylinder  203  extends or retracts, pipe gripper  200  can pivot about pivot pin  202  and can tilt about a horizontal axis passing through pivot pin  202 .  
      Hydraulic power fluid supply conduits  136  extend from one end of each of the valves downwardly to the drilling platform and is there connected to a suitable hydraulic pump for the purpose of supplying the hydraulic power fluid necessary to operate the several hydraulic cylinder and piston assemblies hereinbefore described. Return conduits  137  also project from each of the valves downwardly to the drilling platform to allow exhausted hydraulic fluid to return to a reservoir or sump in the course of recirculation in a conventional fashion.  
      In its standard configuration, a remote control panel subassembly is used to control the movement of jointed articulating boom  110  and pipe gripper  200 . In order to shift valves  401 , electrical solenoids are included in remote control panel subassembly  400 , and are actuated by power signals delivered via conductors extended through a control cable  404  which extends from the drilling platform upwardly to the remote control panel subassembly  400 . Said control cable can be plugged into remote control panel subassembly  400  using a suitable jack.  
       FIG. 6  is a perspective view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing.  FIG. 7  is a side view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing.  
       FIG. 8  depicts a side view of an alternate embodiment of the pipe stabbing apparatus  100  of the present invention. Pipe stabbing apparatus  100  includes jointed articulating boom  110 ; said boom is comprised of boom base member  111  and boom arm member  112 , which are pivotally joined with boom pivot joint  113 . Jointed articulating boom  110  extends and retracts by cooperative motion between boom base member  111  and boom arm member  112 . In this embodiment, boom arm member  112  is actually comprised of upper boom arm member  112   a  and lower boom arm member  112   b.    
      Extension member  500  can be received within lower boom arm member  112   b,  and can be used to selectively extend or contract the overall length of lower boom arm member  112 . In this embodiment, one end of hydraulic cylinder  501  is anchored to upper boom arm member  112   a  with anchor bracket  502  and anchor pin  503 . Hydraulic cylinder  501  further includes piston rod  504 , which is in turn pinned to mounting plate  505  using anchor pin  506 . As piston rod  504  of hydraulic cylinder  501  extends or retracts, the overall length of boom arm member  112  can be selectively controlled. Frequently, it is desirable to adjust the length of boom arm member  112  for purposes of stabbing a section of pipe within a derrick.  
      In operation, the casing stabbing apparatus  110  of the invention will be mounted at some intermediate location within derrick  11 , such as on a cross member thereof as illustrated in  FIG. 1 , using mounting assembly  114 . With the casing stabbing apparatus  110  thus mounted and positioned within derrick  11 , the various hydraulic piston and cylinder assemblies are then used to engage upper casing section  18  hung from upper slips  19  on traveling block  20 .  
      The opposing arcuate jaws  201   a  and  201   b  are opened apart from each other by pivotation of each of the jaws about the respective pivot pins  211   a  and  211   b . With the arcuate casing jaws  201   a  and  201   b  thus opened apart from each other, said jaws are then moved to a position where they surround the suspended upper casing section  18 . This is accomplished by means of the piston and cylinder subassembly previously described.  
      When upper casing section  18  has been thus engaged by opposing arcuate jaws  201   a  and  201   b,  operator  403 , by appropriate manipulation of the control valves on remote control assembly  400 , can cause casing section  18  to be moved in small increments in any direction. Thus, by remote control, operator  403  can move casing section  18  to a position directly above lower casing section  17  held by lower slips  16  in rotary  14 . Then, as traveling block  20  is lowered, the threads at the lower end of suspended upper casing section  18  can be made to precisely align with the mating threads in lower casing section  17  in the vicinity of the rotary table. Suspended upper casing section  18  can be rotated to tighten such mating threads into engagement with each other without damage to said threads, and with a minimum amount of manual manipulation required by personnel on the rig floor. Importantly, the dangerous procedure of having a crew member manually manipulating the heavy casing section from a position high in the derrick is totally eliminated. With the present invention it is not even necessary for the operator of the hydraulically powered casing stabbing apparatus to be in the derrick. When upper casing section  18  has been joined with lower casing section  17 , opposing arcuate jaws  201   a  and  201   b  are opened apart from each other.  
      In many instances, it will be desired, at times when the casing stabbing apparatus  100  is not in use, to move jointed articulating boom  110  to a position where it does not project out over the rig floor  12 , and does not interfere with other pipe or tubular member handling operations.  
      The pipe stabbing apparatus of the invention is particularly efficient and effective in use because it eliminates the need to have one and frequently two persons in the rig derrick who try to manipulate the casing manually, or even to control the hydraulically controlled apparatus of this invention. With the present invention, this control can be entirely from a remote location, such as the rig floor. By the use of the remote control assembly  400 , operator  403  can set up at the optimum location. As such, operator  403  can detect the direction of lean, if any, of the suspended elongated casing section.  
      Although the pipe stabbing apparatus of the present invention has been depicted in a particular form constituting a preferred embodiment, it will be understood that various changes and modifications in the illustrated and described structure can be effected without departure from the basic principles which underlie the invention. Changes and innovations of this type are deemed to be circumscribed by the spirit and scope of the invention except as such spirit and scope may be necessarily limited by the appended claims, or reasonable equivalents thereof.