Patent Publication Number: US-2015075811-A1

Title: Modular apparatus for assembling tubular goods

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 13/597,429, filed Aug. 29, 2012, currently pending 
    
    
     STATEMENTS AS TO THE RIGHTS TO THE INVENTION MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     None 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to an apparatus for assembling and installing pipe in a well. More particularly, the present invention pertains to a pipe running tool that can rotate at high speed, and selectively grip pipe either internally or externally. More particularly still, the present invention pertains to a pipe running tool that can be quickly and easily converted between internal and external pipe gripping simply by changing out modular components. 
     2. Brief Description of the Prior Art 
     Efficiency in connection with oil and gas operations, especially in terms of drilling rate, has been addressed with great earnest for many years. However, drilling rate is not the only variable affecting operational costs; pipe string assembly and installation rate typically has about the same cost-effect as drilling rate. The present invention addresses an increase in efficiency of such pipe string assembly and installation operations (and a resulting decrease in costs associated with such operations) without sacrificing safety concerns. 
     Once a well has been drilled to a desired depth, large diameter and relatively heavy pipe known as “casing” is frequently installed in the well. During installation in a well, casing is typically inserted into the pre-drilled well bore in a number of separate sections of substantially equal length referred to as “joints.” The joints, which generally include threaded connections, are typically joined end-to-end at the earth&#39;s surface (typically from a drilling rig) in order to form a substantially continuous “string” of pipe that reaches downward into a well. After the casing is installed within the well bore, the pipe is usually cemented in place. 
     During the pipe installation process, additional sections of pipe are added to the upper end of the pipe string at the rig in order to increase the overall length of the pipe string and its penetration depth in a well bore. The addition of pipe sections at the surface is repeated until a desired length of pipe is inserted into the well. The rate of assembly and installation of the casing can amount to many hours of total work time which, in turn, equates to higher costs. As such, time reduction in pipe string assembly and installation operations can result in significant cost reduction. 
     Conventional casing installation operations typically involve specialized crews and equipment mobilized to a well site for the specific purpose of assembling casing and installing such casing into a well. Recently, a method of running casing using a rig&#39;s top drive system, together with specialized casing running tools (RT&#39;s), has become increasingly popular. In many cases, casing can be run more efficiently and for less cost using an RT, compared to conventional casing crews and equipment, because RT&#39;s can be used to pick up and stab joints of casing and to provide torque to make up threaded casing connections. As a result, specialized casing tongs are frequently not needed, and fewer personnel are required on and around the rig floor during the casing running operations. 
     In most cases, a RT is connected immediately below a rig&#39;s top drive unit prior to commencement of casing operations. A single-joint elevator, supported by a RT, is typically used to lift individual joints of casing from a V-door or pipe rack into a derrick in vertical alignment over a well. The top drive and attached RT are lowered until the RT is proximate to the top of the new joint being added. The slips of the RT are set on the new joint of casing, and the top drive is actuated to apply the required torque (through the RT) to make up the casing to the upper end of the casing string previously installed in a well. At times, during the lowering of the pipe string into the well, the pipe string can be rotated and/or reciprocated using the RT to facilitate installation in the well. 
     In certain circumstances, it is beneficial for an RT to grip a pipe section internally (i.e., within the internal bore of such pipe), while in other circumstances it may be better to grip such pipe externally (i.e., on the outer surface of such pipe). However, because such functions generally require very different RT equipment configurations, most RT systems are designed for either internal gripping of pipe or external gripping of pipe, but cannot be converted from one method to the other. Further, existing RT systems generally provide for relatively low rotational rate (rpm), primarily due to limitations associated with hydraulic swivel seals. 
     In economic interest, the feed rate during the lowering of a pipe string into a well should be maximized, within the limits of safety considerations. Thus, there is a need for an RT that can pick up, assemble, rotate, and reciprocate casing or other pipe during installation operations, while having the ability to fill up fluids and compensate such casing or pipe during critical make up or break out procedures. The RT should allow for quick and efficient conversion between internal and external pipe gripping methods, while also permitting high rotational rates. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention comprises a modular RT that can pick up, assemble, rotate, and reciprocate casing or other pipe during installation operations, while having the ability to fill up fluids and compensate such casing or pipe during critical make up or break out procedures. 
     In the preferred embodiment, the present invention comprises a modular RT that can be used in connection with top drive systems to quickly, efficiently and safely assemble and install tubular goods (including, without limitation, large diameter or heavy weight casing) into a well. The modular RT of the present invention can permit gripping of pipe either internally (i.e., within the internal bore of such pipe) or externally (i.e., on the outer surface of such pipe). By simply changing out certain modular components, the tool can be quickly modified between an internal and an external gripping tool that allows gripping of larger diameter pipe. 
     The RT of the present invention further comprises a dynamic fluid swivel that conveys control fluid (typically hydraulic oil) to different parts of the RT in order to facilitate actuation of said RT, while permitting rotation of said RT and the application of torque to pipe gripped by said RT. However, the RT of the present invention isolates elevated control fluid pressures from such swivel during rotation of the RT. As a result, the fluid seals of said fluid swivel last much longer than conventional swivel seal assemblies, while permitting rotation at much higher rates than conventional RT&#39;s. 
     Any dimensions set forth herein and in the attached drawings are illustrative only and are not intended to be, and should not be construed as, limiting in any way. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, the drawings show certain preferred embodiments. It is understood, however, that the invention is not limited to the specific methods and devices disclosed. Further, dimensions, materials and part names are provided for illustration purposes only and not limitation. 
         FIG. 1  depicts the modular pipe running assembly of the present invention configured for gripping against the external surface of a section of pipe. 
         FIG. 2  depicts the modular pipe running assembly of the present invention configured for gripping against the internal surface of a section of pipe. 
         FIG. 3  depicts a side partial sectional view of a modular actuator assembly of the present invention. 
         FIG. 4  depicts a side partial sectional view of a compensator piston and spline coupling of the present invention. 
         FIG. 5  depicts a bottom view of the compensator piston and spline coupling of the present invention depicted in  FIG. 4 . 
         FIG. 6  depicts a side perspective view of a spline coupling member of the present invention. 
         FIG. 7  depicts a side perspective view of a drive shaft of the present invention. 
         FIG. 8  depicts a side partial sectional view of a drive shaft and mandrel piston of the present invention. 
         FIG. 9  depicts a side perspective view of components of a swivel assembly of the present invention. 
         FIG. 10  depicts a detailed view of fluid channels and seals of the swivel assembly components of the present invention depicted in  FIG. 9 . 
         FIG. 11  depicts a side, partial sectional view of a control fluid manifold of the present invention. 
         FIG. 12  depicts a rear view of a control fluid manifold of the present invention. 
         FIG. 13  depicts a top view of a control fluid manifold of the present invention. 
         FIG. 14  depicts an overhead view of a control fluid manifold of the present invention. 
         FIG. 15  depicts a sectional view of a control fluid manifold of the present invention along line A-A of  FIG. 14 . 
         FIG. 16  depicts a sectional view of a control fluid manifold of the present invention along line B-B of  FIG. 14 . 
         FIG. 17  depicts a sectional view of a control manifold of the present invention along line C-C of  FIG. 14 . 
         FIG. 18  depicts a side partial sectional view of an external pipe gripping assembly of the present invention. 
         FIG. 19  depicts a side partial sectional view of an internal pipe gripping assembly of the present invention. 
         FIG. 20  depicts a side sectional view of actuator assembly of the present invention. 
         FIG. 21  depicts an alternate side sectional view of actuator assembly of the present invention depicted in  FIG. 20 . 
         FIG. 22  depicts a schematic view of certain control processes of an actuator assembly of the present invention. 
         FIG. 23  depicts side sectional view of an alternative embodiment actuator assembly that is not equipped with a weight compensator assembly. 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 
     Referring to the drawings,  FIG. 1  depicts modular pipe running assembly  100  of the present invention configured for gripping against the external surface of a length of pipe.  FIG. 2  depicts alternative embodiment modular pipe running assembly  110  of the present invention configured for gripping against the internal surface of a length of pipe. 
     As depicted in  FIG. 1 , modular pipe running assembly  100  can be connected beneath a rig&#39;s existing top drive assembly, and generally comprises axially aligned modular actuator assembly  10  and external pipe gripping assembly  130 . In the embodiment depicted in  FIG. 2 , modular pipe running assembly  110  comprises many of the same components as modular pipe running assembly  100  depicted in  FIG. 1 , except that internal pipe gripping assembly  150  is connected to actuator assembly  1 , rather than external pipe gripping assembly  130 . 
     Referring to  FIG. 1 , in the preferred embodiment modular pipe gripping assembly  100  has an adjustable mounting assembly for connecting an optional stabbing assembly to said modular pipe gripping assembly  100 . It is to be observed that the size, shape and specific configuration of said adjustable mounting assembly can vary depending upon a number of variables including, without limitation, top drive design; however, as depicted in  FIG. 1 , said adjustable mounting assembly generally comprises bilateral base members  201  surmounted on clevis bracket members  204  which are attached to modular pipe running assembly  100 . Adjustable bilateral arm members  202  are telescopically and adjustably disposed within said base members  201  and have angle members  205  that permit the angle of said arm members  202  to be adjusted, as well as bilateral interference plates  203  that can be beneficially positioned in proximity to a rig&#39;s top drive assembly. 
     Still referring to  FIG. 1 , optional stabbing assembly comprises bilateral cylinder barrels  211  pivotally connected to bracket members  204 . Piston rods  212  are telescopically disposed in said cylinder barrels  211 , and can be extended or retracted using hydraulic, pneumatic or other power source well known to those having skill in the art. Connecting cables  213  extend from said cylinder piston rods  212  to single-joint pipe elevators  214 . As depicted in  FIG. 1 , elevators  214  are used to grip pipe section  300  having upper connection collar, which can be a joint of casing or other tubular good, in a manner well known to those having skill in the art. 
     Referring to  FIG. 2 , in the preferred embodiment modular pipe gripping assembly  110  is also equipped with an adjustable mounting assembly for connecting an optional stabbing assembly to said modular pipe gripping assembly  110 . Said adjustable mounting assembly and stabbing assembly have substantially the same components as depicted in  FIG. 1 , and can likewise be used to grip a length of pipe, such as pipe section  310  having upper connection collar  311 . 
       FIG. 3  depicts a side sectional view of an actuator assembly  10  of the present invention equipped with a weight compensator assembly to provide weight compensation as described more fully herein. As noted above, said actuator assembly  10  can be used as a component of either modular pipe running assembly  100  depicted in  FIG. 1 , or alternative embodiment modular pipe running assembly  110  depicted in  FIG. 2 . Further, as depicted in  FIG. 3 , said actuator assembly  10  is equipped with a weight compensator which is frequently beneficial during pipe assembly and installation operations. Generally, said weight compensator assembly is used to compensate for the weight of a top drive unit, pipe running assembly and/or pipe weight, particularly during pipe connection (make-up) operations; it is generally beneficial to remove excessive weight from a section of pipe during the thread run when such pipe is being threadedly connected to another section or string of pipe. 
     Still referring to  FIG. 3 , crossover  2  has upper threaded connection  1  that provides an interface for connecting actuator assembly  10  of a modular pipe running assembly to a top drive quill. If required, crossover  2  can be easily changed so that upper threaded connection  1  can mate with virtually any top drive quill or other configuration. Torque locking tabs  3  permit crossover  2  to be easily made up, while allowing for transmission of torque from a top drive to said modular pipe running assembly in a manner generally described herein. 
     Actuator assembly  10  comprises central body member  50  having central axial through bore  51 . Compensator piston  60  is connected to crossover  2 , and is movably disposed within said central through bore  51  of central body member  50 . Compensator piston  60  is disposed within said through bore  51  of central body member. Said compensator piston  60  has central axial bore  61  with spline coupling  190  disposed therein. 
     Drive shaft  30 , itself having central axial through bore  31 , is disposed within said central axial bore  61  of compensator piston  60 . Drive shaft  30  is also disposed through sealed divider piston  14  and mandrel piston  70  (having lower threads  71  and torque locking tab recesses  72 ). Sealed divider retention ring  15  retains sealed divider piston  14 . Mud seal block  4  is connected to the upper end of drive shaft  30 . 
     Outer actuator sleeve  20  has inner bore  21  which, together with body member  50 , defines annular spaces between said outer actuator sleeve  20  and body member  50 . Accumulator piston  12 , ported divider piston  11  and external actuator piston  40 , having external threads  42 , are disposed within said bore  21  of outer actuator sleeve  20 . Lower gland member  18  is connected to the base of body member  50 . Lower tubular member  32  is connected to drive shaft  30  and extends through a central bore in mandrel piston  70 . External actuator piston gland  41  is disposed below said external actuator piston  40 . 
     Body member  50  is rotatably disposed within swivel sleeve assembly  90 . Quick connect/disconnect control manifold assembly  7  quickly connects to (and disconnects from) swivel sleeve assembly  90 , and can transmit hydraulic fluid to actuator assembly  10  in order to control operation of said actuator assembly  10 . Check valve manifold assembly  80  having pilot-operated check valve  81  is sealably connected to body member  50 . Upper fluid seal member  91  and lower fluid seal member  92  are disposed above and below swivel sleeve assembly  90 ; retention plate  93  is also disposed on said swivel sleeve assembly  90 . 
       FIG. 4  depicts a side, partial sectional view of compensator piston  60  and spline coupling  190  of the present invention. Compensator piston  60  has substantially tubular body section  68  having central through bore  61 . Compensator piston  60  comprises upper threaded connection  62  for connection to a crossover (such as crossover  2  depicted in  FIG. 3 ), as well as lower receptacle section  63 ; in the preferred embodiment, said lower receptacle section  63  has a larger diameter than body section  68 . Compensator piston  60  further has at least one notch or recess  66  at its upper end for receiving a corresponding torque locking tab (such as from crossover  2  depicted in  FIG. 1  not shown in  FIG. 4 ). In the preferred embodiment, substantially parallel channels  64  and sealing elements  65  are disposed around the outer circumferential surface of lower receptacle section  63 . In the preferred embodiment, said sealing elements  65  comprise elastomeric seals. Spline coupling  190  having internal spline profile  191  is disposed within lower receptacle  63 . 
       FIG. 6  depicts a side perspective view of spline coupling  190  of the present invention. In the preferred embodiment, said spline coupling  190  has cylindrical body section  192  having internal spline profile  191 . A plurality of flange-like projections  193  extend radially outward from body member  192 . In the preferred embodiment, said projections  193  have substantially rounded edges, and bores  194  extending through said projections. 
       FIG. 5  depicts a bottom view of compensator piston  60  and spline coupling  190  of the present invention depicted in  FIG. 6 . Said spline coupling  190 , having internal spline profile  191 , is received within lower receptacle section  63  of compensator piston  60 . Flange-like radial projections  193  fit between and mate with corresponding finger members  67  extending inward from the inner surface of lower receptacle section  63  of compensator piston  60 . In the preferred embodiment, projections  193  are shaped to fit between said finger members  67 ; engagement of said projections  193  and finger members  67  permits the transmission of torque between spline coupling  190  and compensator piston  60 . Anchor bolts  195  secure spline coupling  190  within compensator piston  60 , and said anchor bolts can be joined by optional retention cable  196 . 
       FIG. 7  depicts a side perspective view of drive shaft  30  of the present invention. Drive shaft  30  has central axial through bore  31 , upper sealing element  33  and upper threaded connection  34 , upper external spline profile  35 , lower external spline profile  36  and lower sealing element  37 . Body section  38 , having a substantially smooth outer surface, is disposed between said upper external spline profile  35  and lower external spline profile  36 . In the preferred embodiment, upper sealing element  33  and lower sealing element  37  comprise elastomeric seals. 
       FIG. 8  depicts a side, partial sectional view of drive shaft  30  mated with mandrel piston  70  of the pipe running assembly of the present invention. Drive shaft  30  has central axial through bore  31 , upper sealing element  33 , upper threaded connection  34  and upper external spline profile  35 , and is partially received within mandrel piston  70 . 
     Mandrel piston  70  has cylindrical body section  73  defining a substantially smooth outer surface. Upper receptacle section  74  has central bore  75  having an inner spline profile (not visible in  FIG. 8 ). In the preferred embodiment, substantially parallel channels  76  and sealing elements  77  are disposed around the outer circumferential surface of upper receptacle section  74 . In the preferred embodiment, said sealing elements  77  comprise elastomeric seals. Mandrel piston  70  also has lower threads  71  and torque locking tab recesses  72 . 
     Still referring to  FIG. 8 , drive shaft  30  is partially received with bore  75  of mandrel piston  70 . Lower external spline profile  36  of drive shaft  30  mates with inner spline profile of bore  75 , thereby facilitating the transfer of torque between said drive shaft  30  and mandrel piston  70 . Lower sealing element  37  of drive shaft  30  seals against an inner surface of mandrel piston  70 , thereby creating a fluid pressure seal. 
       FIG. 9  depicts an overhead perspective view of an adjustable mounting assembly and swivel assembly  90  of the present invention. Said adjustable mounting assembly generally comprises bilateral base members  201  surmounted on clevis bracket members  204 . Adjustable bilateral arm members  202  are telescopically disposed within said base members  201  and have angle members  205 , as well as bilateral interference plates  203  that can be beneficially positioned in proximity to a rig&#39;s top drive assembly. 
     Swivel assembly  90  generally comprises body member  94  defining central through bore  95 . In the preferred embodiment, quick connect control fluid manifold assembly  7  is attached to said swivel body member  94 . Although not depicted in  FIG. 9 , central body member  50  of actuator assembly  10  can be rotatably received within central bore  95  of swivel body member  94 . 
       FIG. 10  depicts a detailed view of a portion of swivel assembly  90  depicted in  FIG. 9 . A plurality of stacked channels  96  are disposed along the inner surface of swivel body member  94  that is defined by central bore  95 . Fluid sealing elements  97  are disposed between each of said channels  96 . In the preferred embodiment, said fluid sealing elements  97  comprise elastomeric seals. 
     Although not depicted in  FIGS. 9 and 9   a , a plurality of fluid channels are also disposed within body member  50  of actuator assembly  10  which is rotatably disposed in bore  95  of body member  94 . At least one fluid channel in said body member  50  corresponds with an aligned fluid channel  96  of swivel assembly  90 . As such, control fluid (for example, hydraulic oil) can be supplied to quick connect manifold assembly  7  from an external or remote fluid source. Such fluid can be pumped through said quick connect manifold assembly  7 , through bore(s) extending through swivel body member  94 , into a desired channel  96  in said swivel body member  94 , and into a corresponding fluid channel in body member  50  of actuator assembly. Importantly, although said swivel body member  94  does not rotate, actuator assembly body member  50  is capable of rotation within bore  95  of body member  94  of swivel assembly  90 , yet control fluid can be pumped from said remote location through swivel assembly into actuator assembly  10  to control functioning of the pipe running assembly of the present invention. 
       FIG. 11  depicts a side perspective view of quick connect manifold  7  of the present invention. Although manifold  7  can have many different configurations, in the preferred embodiment said manifold  7  comprises body section  8 . Locking mechanism  9  having handle  9   a  provides a means for quickly attaching said manifold  7  to swivel assembly  90 . Said manifold  7  also comprises various valves, described in more detail herein, as well as ports for connection to control fluid lines. In the preferred embodiment, said lines supply hydraulic oil to manifold  7  from a remote fluid source. 
       FIG. 12  depicts a rear view of manifold  7  of the present invention, while  FIG. 13  depicts a top view of said manifold  7 . In the preferred embodiment, said manifold  7  comprises hydraulic pressure reducing valve  7   a , hydraulic relief valve  7   b , air piloted 2-way hydraulic valve  7   c , hydraulic kick down relief valve  7   d , air pilot line  7   e  for air piloted valve  7   c , pressure input  7   f  to pressure reducing valve, pilot control line  7   g  for sampling pressure acting on compensator piston of actuator assembly, return line  7   h  for pressure relief valve  7   b , pilot line  7   i  to release pilot operated check valve  81  (not shown in  FIG. 12  or  13 ) once valve  7   c  is opened by air pilot signal, slip set signal line  7   k  and slip release signal line  7   j.    
       FIG. 14  depicts an overhead view of manifold assembly  7  of the present invention.  FIG. 15  depicts a sectional view of manifold  7  of the present invention along line A-A of  FIG. 14 .  FIG. 16  depicts a sectional view of manifold  7  of the present invention along line B-B of  FIG. 14 .  FIG. 17  depicts a sectional view of manifold  7  of the present invention along line C-C of  FIG. 14 . 
       FIG. 18  depicts a side, partial sectional view of external pipe gripping assembly  130  of the present invention. External pipe gripping assembly  130  comprises slip bowl body member  131  defining lower surface  132 . External pipe gripping assembly  130  further comprises upper push plate  133  having threads  134 . Said threads  134  are adapted to mate with threads  42  on external actuator piston  40  of an actuator assembly (such as actuator assembly  10  depicted in  FIG. 3 ) when the pipe gripper of the present invention is configured in the external pipe gripping mode. Slip bowl member  131  further comprises threaded section  135  that extends through a bore in upper push plate  133 . Threads  135  are adapted to mate with lower threads  71  of mandrel piston  70  of an actuator assembly (such as actuator assembly  10  depicted in  FIG. 3 ). 
     Slip bars  136  are pivotally mounted at their upper end to push plate  133  with clevis mounts  137  using upper pivot pins  138 . Said slip bars  136  are pivotally mounted at their lower end to slip body  140  using lower pivot pins  139 . Slip body  140  has tapered shoulders  142  and slip dies  141  or other gripping means disposed on the inner surface of said slip body  140 . Said slip body  140  is movably disposed on inner tapered surfaces  143  of slip bowl  131 , which provide support surfaces for tapered shoulders  142  of slip body  140 . Grease ports  144  extend through slip bowl member  131 , and provide a path for supplying lubricant to opposing tapered surfaces  142  and  143 . Bottom bell extends from the bottom of pipe gripping assembly  130 , and has tapered guide  155  to guide or direct said pipe gripping assembly  130  over the upper end of a section of pipe (such as pipe section  300 ). 
     Arbor member  145  having outer sleeve  146  and inner through-bore  147  extends through slip bowl member  131  and connects to a fluid fill-up tool assembly  150 . Said fluid fill-up assembly  150  is well known to those having skill in the art. Said fluid fill-up tool assembly  150 , which has elastomeric sealing cup  151  and cup ring  152 , can extend into the bore of a section of pipe  300  having connection collar member  301  that is gripped by external pipe gripping assembly  130 . When said fluid fill-up tool is inserted into the upper end of a section of pipe (such as pipe section  300 ), valve assembly  153  is opened to allow fluid flow through said fluid fill-up tool. However, when said fluid fill-up tool assembly  150  is removed from a section of pipe, said valve assembly  153  closes, thereby preventing drilling mud or other fluid from spilling out of or otherwise flowing from the bottom of a pipe running assembly of the present invention. 
       FIG. 19  depicts a side, partial sectional view of an internal gripping assembly  160  of the present invention. Internal gripping assembly  160  comprises internal mandrel  161  having tapered shoulder surfaces  162  and external threaded section  165 . Said internal mandrel  161  is disposed through bump plate  166  having upper connection  167  member with internal threads  168 . When incorporated in the pipe running assembly of the present invention, said threads  168  are adapted to mate with threads  42  on external actuator piston  40  of an actuator assembly (such as actuator assembly  10  depicted in  FIG. 3 ), while threads  165  are adapted to mate with lower threads  71  of mandrel piston  70  of an actuator assembly (such as actuator assembly  10  depicted in  FIG. 3 ). 
     Slip die member  163  having a plurality of outwardly facing pipe gripping dies or other frictional gripping means is movably disposed on tapered shoulder surfaces  162  of mandrel  161 . Casing push bar  169  having loading shoulder  169   a  extends from slip die member  163  to spacer member  170 . Compression spring  171  is mounted below movable slip die member  163  on adjustable base  172 . Adjustable base  172  can be moved to adjust the loading on said compression spring  171 . 
     A fluid fill-up assembly  150 , well known to those having skill in the art, has elastomeric sealing cup  151  and cup ring  152 , can extend into the bore of a section of pipe  310  having connection collar member  311  that is gripped by external pipe gripping assembly  130 . When said fluid fill-up tool is inserted into the upper end of a section of pipe (such as pipe section  300 ), valve assembly  153  is opened to allow fluid flow through said fluid fill-up tool. However, when said fluid fill-up tool assembly  150  is removed from a section of pipe, said valve assembly  153  closes, thereby preventing drilling mud or other fluid from spilling out of or otherwise flowing from the bottom of the pipe running assembly of the present invention. 
       FIG. 20  depicts a side sectional view of actuator assembly  10  of the present invention, while  FIG. 21  depicts an alternate side sectional view of actuator assembly  10  of the present invention depicted in  FIG. 20 . Referring to  FIG. 20 , in operation, control fluid (typically hydraulic oil) is supplied to actuator assembly  10  from a remote source, such as a control and pump assembly that can be located on a rig floor or other convenient remote location. 
     Still referring to  FIG. 20 , in order to grip a section of pipe, a desired control fluid is supplied to control manifold assembly  7  via hoses or other acceptable means. Said control fluid flows through channel  220  in control manifold assembly  7 , and into corresponding fluid channel  221  in body member  94  of swivel assembly  90 , which is in turn in communication with an isolated channel  96  of said body member  94 . Such fluid within an isolated flow channel  96  then enters aligned fluid channel  222  in body member  50 . In this manner, control fluid can be supplied to channel  222  (and other similarly configured channels) in body member  50 , even when said body member  50  is capable of rotation relative to swivel assembly  90 . 
     Control fluid flows through fluid channel  222 , as well as check valve assembly  80  having a pilot operated check valve  81  (not depicted in  FIG. 20 ) well known to those having skill in the art. When actuated, said pilot operated check valve  81  prevents fluid entering body member  50  through said check valve assembly  80  from flowing back through said check valve assembly  80 . After flowing through check valve assembly  80 , fluid continues flowing into body member  50  via flow channel  222 . 
     Fluid from flow channel  222  enters channel  223  and flows through a port in accumulator stop ring  11 . Said fluid passes through said ported accumulator stop ring  11  and enters annular chambers  230  and  231 . Fluid entering chamber  230  provides downward force on external actuator piston  40 , causing said external actuator piston  40  to move in a downward direction. Fluid entering chamber  231  acts on accumulator piston  12 , thereby compressing gas stored in sealed chamber  232 . In this manner, interaction between fluid in chamber  231 , accumulator piston  12 , and gas in chamber  232  act as a fluid accumulator for storing energy. 
     When an internal pipe gripping assembly is being used, fluid flows from channel  222  into channel  224  and acts on mandrel piston  70 , forcing said piston in an upward direction. However, in the preferred embodiment, when an external pipe gripping assembly is being used, a rigid spacer can be installed within chamber  240  between mandrel piston  70  and sealed divider piston  14 , thereby preventing upward movement of said mandrel piston  70 . 
     Similarly, when a weight compensation assembly is being used (such as depicted in the embodiment of actuator assembly  10  depicted in  FIGS. 3 and 20 ), control fluid flows through channel  250  in control manifold assembly  7 , and into corresponding fluid channel  221  in body member  94  of swivel assembly  90 , which is in turn in communication with an isolated channel  96   a  of said body member  94 . Such fluid then enters aligned fluid channel  252  in body member  50 . In this manner, control fluid can be supplied to channel  252  (and other similarly configured channels) in body member  50 , even when said body member  50  is capable of rotation relative to swivel assembly  90 . 
     Control fluid flows through fluid channel  252  and through check valve assembly  80  having a pilot operated check valve  81  (not depicted in  FIG. 20 ) well known to those having skill in the art. When actuated, said pilot operated check valve  81  prevents fluid downstream of said check valve assembly  80  from flowing back through said check valve assembly  80 . After flowing through check valve assembly  80 , fluid continues flowing into body member  50  via flow channel  252 . Such control fluid enters compensator chamber  260  formed between compensator piston  260  and body member  50 . In the preferred embodiment, said fluid flow in and out of compensator chamber  260  can be controlled to compensate for a predetermined weight value. 
       FIG. 21  depicts an alternate side sectional view of actuator assembly  10  of the present invention depicted in  FIG. 20  illustrating certain control paths for retraction of actuator assembly  10  (such as, for example, when a gripping assembly is to release from a section of pipe). Specifically, control fluid flows through channel  270  in control manifold assembly  7 , and into corresponding fluid channel  271  in body member  94  of swivel assembly  90 , which is in turn in communication with an aligned isolated channel  96   b  of said body member  94 . Such fluid then enters aligned fluid channel  272  in body member  50 . In this manner, control fluid can be supplied to channel  272  (and other similarly configured channels) in body member  50 , even when said body member  50  is capable of rotation relative to swivel sleeve assembly  90 . 
     Control fluid flows through fluid channel  272  and through check valve assembly  80  having a pilot operated check valve  81  (not depicted in  FIG. 20 ) well known to those having skill in the art. Pilot operated check valve  81  (not depicted in  FIG. 21 ) of check valve assembly  80  is actuated to permit bleed-off control line pressure previously supplied downstream of said check valve. Further, control fluid also flows through channels  272  and  273 ; such control fluid acts on external actuator piston  40  and forces said piston  40  in an upward direction and mandrel piston  70  in a downward direction. As such, said external actuator piston  40  and mandrel piston  70  move in directions opposite from the actuation directions described in connection with  FIG. 20 . As noted above, is to be observed that when an external pipe gripping assembly is being used, a rigid spacer installed within chamber  240  between mandrel piston  70  and sealed divider piston  14  prevents movement of said mandrel piston  70 . 
       FIG. 22  depicts a schematic view of certain control processes of an actuator assembly of the present invention. A slip set signal can be generated by supplying fluid to line  7   k  of control manifold  7 . Said fluid flows through check valve  81  where it is fed into the rod area of mandrel piston  70 , causing said mandrel piston  70  to retract. At the same time, fluid is supplied to chamber  230  on the bore side of external actuator piston  40 , causing it to extend. 
     Once the mandrel piston  70  and external actuator piston  40  cause the slips to be set for either a modular internal pipe gripping assembly, or a modular external pipe gripping assembly, fluid fills accumulator chamber  231 . When the pressure reaches a predetermined level, kick down relief valve  7   d  opens. The slip set signal  7   k  (fluid) then flows through valve  7   d  and is circulated back to the fluid source/control cabinet (not shown) via  7   j  slip release signal line. At this point, fluid pressure on the bore area of mandrel  70 , chamber  230 , and accumulator chamber  231  is trapped by check valve  81  once slip set pressure is reached and the system converts to control fluid circulation mode. This pressure is maintained by accumulator piston  12 . 
     Control fluid circulation is maintained at a predetermined pressure that is less than the initial setting pressure. At this pressure the hydraulic sealing elements of a fluid swivel assembly (not shown in  FIG. 22 ), such as sealing elements  97  of swivel assembly  90 , relax and are cooled by circulating flow, allowing rotation at higher speeds without damaging said swivel sealing elements. 
     In order to release slips, when pilot line  7   i  is pressurized through control fluid manifold  7  and swivel assembly  90 , it forces pilot operated check  81  to open. Slip release signal  7   j  (fluid) is then permitted to feed the rod side of external actuator piston  40  causing said piston to retract. At the same time, fluid is also supplied to the bore area of mandrel piston  70  causing it to extend. These combined actions cause the slips to release from a gripping engagement with pipe. 
       FIG. 23  depicts a side sectional view of an alternative embodiment actuator assembly  120  that, unlike actuator assembly  10  depicted in  FIG. 3  is not equipped with a weight compensator assembly. The components of alternative embodiment actuator assembly  120  operate in a manner that is substantially similar to that described in detail herein. 
     In operation, the pipe running assembly of the present invention can be connected immediately below a rig&#39;s top drive unit prior to commencement of casing operations. When gripping of the external surface of pipe is desired, external pipe gripping assembly  130  is attached to actuator assembly  10 , generally in the manner depicted in  FIG. 1 . Alternatively, when gripping of the internal surface of pipe is desired, internal pipe gripping assembly  160  is attached to actuator assembly  10 , generally in the manner depicted in  FIG. 2 . 
     A single-joint elevator (such as elevator  214  in  FIGS. 1 and 2 ) is typically used to lift individual joints of casing from a V-door or pipe rack into a derrick in vertical alignment over a well. Said top drive assembly and attached pipe running assembly of the present invention are lowered so that any attached fluid fill-up tool (such as fluid fill-up tool  150 ) is inserted into the bore of the new joint being added. The pipe running assembly can be actuated to grip the new joint of casing, and the top drive is actuated to apply the required torque (through the pipe running assembly of the present invention) to make up the casing to the upper end of a casing string previously installed in the well and supported at the rig floor from lower spider slips. After the new joint of pipe has been made up to the existing string of pipe in the well, said lower spider slips can be released. 
     When the lower spider slips are released, the entire string of casing is supported by the top drive assembly and pipe running assembly of the present invention. At this point, said pipe can be lowered into said well. During the lowering of the pipe string into the well, the pipe string can be rotated and/or reciprocated, and drilling fluids can be circulated, to facilitate installation of the pipe string in the well. 
     When gripping of the external surface of pipe is desired, external pipe gripping assembly  130  depicted in  FIG. 18  is connected to the bottom of an actuator assembly, such as actuator assembly  10  depicted in  FIG. 3 , which is in turn mounted to a quill of a top drive assembly. Specifically, threads  135  of slip bowl member  131  are connected to lower threads  71  of mandrel piston  70  of an actuator assembly (such as actuator assembly  10  depicted in  FIG. 3 ), while threads  134  of upper push plate  133  are connected to threads  42  of external actuator piston  40  (such as actuator assembly  10  depicted in  FIG. 3 ). When setting of the actuator assembly and gripping of pipe is desired, control fluid is supplied to actuator assembly  10  from a pump/control console situated in a convenient remote location (such as on a rig floor, for example). Such control fluid is supplied to said actuator assembly through control fluid manifold assembly  7 . 
     When said actuator assembly  10  is actuated as depicted in  FIG. 20  and discussed herein, external actuator piston  40  moves in a downward direction. Such downward force by external actuator piston  40  acts on upper push plate  133 , forcing slip bars  136  in a downward direction. As slip bars  136  are urged downward, such slip bars  136  impart downward force on slip assembly  140 , causing tapered shoulders  142  to ride down inner tapered surfaces  143  of slip bowl member  131  which, in turn, forces gripping dies  141  inward in gripping engagement against the outer surface of pipe section  300 . Further, as surface  132  of slip bowl member  131  is lowered, it can contact upper collar member  301  of pipe section  300 ; any such upward forces imparted by said pipe section  300  on said slip bowl assembly  131  further forces slip assembly  140  inward, increasing the grip on pipe section  300 . When release of said gripping assembly from said pipe is desired, the release process of actuation assembly  10  depicted in  FIG. 21  is employed. 
     Similarly, when gripping against the internal surface of pipe is desired, internal pipe gripping assembly  160  depicted in  FIG. 19  is connected to the bottom of an actuator assembly (instead of external pipe gripping assembly  130 ), such as actuator assembly  10  depicted in  FIG. 3 , which is in turn mounted to a quill of a top drive assembly. Specifically, threads  165  of central mandrel  161  are connected to lower threads  71  of mandrel piston  70  of an actuator assembly (such as actuator assembly  10  depicted in  FIG. 3 ), while threads  168  of upper connection member  167  are connected to threads  42  of external actuator piston  40  (such as actuator assembly  10  depicted in  FIG. 3 ). When setting of the actuator assembly and gripping of pipe is desired, control fluid is supplied to actuator assembly  10  from a pump/control console situated in a convenient remote location (such as on a rig floor, for example). Such control fluid is supplied to said actuator assembly through control fluid manifold assembly  7 . 
     As said mandrel piston  70  provides upward force on central mandrel  161 , external actuator piston  40  provides opposing downward force on upper connection member  167 . As central mandrel  161  is forced upward, casing push bar  170  imparts downward force on slip dies  163 , causing said slip dies  163  to ride down tapered surfaces  162  and, in turn, urging said slip dies  163  outward until said slip dies  163  are in gripping engagement against the inner surface of pipe section  310 . 
     When release of said gripping assembly from said pipe is desired, the release process of actuation assembly  10  depicted in  FIG. 21  is employed. In such case, casing push bar releases from slip dies  163 , allowing compression spring  171  to impart upward force on said slip dies  163  and move such slip dies  163  out of gripping engagement with the inner surface of pipe section  310 . 
     Because all control lines are connected to single control fluid manifold assembly  7 , which in turn quickly and easily connects to the swivel assembly, the present invention eliminates the need for personnel to connect individual control lines or hoses to the pipe running assembly of the present invention. As a result, the chance of improper connection of such lines or hoses is greatly reduced. Further, safety is improved, because personnel are not required to connect/disconnect such individual lines/hoses at elevated locations. 
     Further, the pipe running assembly of the present invention permits easy and efficient conversion between pipe gripping methods (that is, gripping the inner or outer surface of pipe). By changing a modular pipe gripping assembly, the pipe running assembly of the present invention can be quickly and inexpensively converted from an internal pipe gripping device to an external pipe gripping device, or vice versa. Further, the pipe running assembly of the present invention permits the transfer of torque, as well as the flow of drilling mud or other fluids, though said device. As such, the pipe running assembly of the present invention (including, without limitation, pistons and other elements having spline profiles) permits the rotation and reciprocation of pipe, as well as the circulation of drilling mud or other fluids through said assembly, during the pipe installation process. 
     Additionally, the pipe running assembly of the present invention traps control fluid pressure downstream of a check valve assembly that isolates said pressure from the fluid swivel assembly of the present invention. As a result, once a target pressure has been achieved and the gripping assembly of the present invention has been actuated, fluid pressure can be relieved from said fluid swivel assembly. The hydraulic sealing elements of a fluid swivel assembly, such as sealing elements  97  of swivel assembly  90 , relax and are cooled by circulating flow of such control fluid. As a result, said sealing elements of the swivel assembly of the present invention are not exposed to elevated pressures during rotation of the pipe running assembly of the present invention, thereby allowing said assembly to rotate at higher speeds without damaging said swivel sealing elements. 
     The above-described invention has a number of particular features that should preferably be employed in combination, although each is useful separately without departure from the scope of the invention. While the preferred embodiment of the present invention is shown and described herein, it will be understood that the invention may be embodied otherwise than herein specifically illustrated or described, and that certain changes in form and arrangement of parts and the specific manner of practicing the invention may be made within the underlying idea or principles of the invention.