Abstract:
A valve, such as a ball valve, is assembled and carried by a running tool. The valve is actuated by an actuator that is triggered by the running tool, and thus opens and closes communication between the drill pipe and the volume below the running tool. An actuating cam is assembled below the running tool that interfaces the actuator. The actuating cam is threaded such that it travels axially as the drill pipe is turned. A profile on the actuating cam is timed with the function of the running tool and controls the action of the actuator such that the valve is open when the running tool function requires communication with the volume below the running tool and the valve is closed when the running tool needs to be pressurized.

Description:
FIELD OF THE INVENTION 
     This invention relates in general to subsea tools and in particular to a remotely operated drill pipe valve. 
     BACKGROUND OF THE INVENTION 
     A subsea well of the type concerned herein will have a wellhead supported on the subsea floor. One or more strings of casing will be lowered into the wellhead from the surface, each supported on a casing hanger. The casing hanger is a tubular member that is secured to the threaded upper end of the string of casing. The casing hanger lands on a landing shoulder in the wellhead, or on a previously installed casing hanger having larger diameter casing. Cement is pumped down the string of casing to flow back up the annulus around the string of casing. Afterward, a packoff is positioned between the wellhead bore and an upper portion of the casing hanger. This seals the casing hanger annulus. 
     One type of packoff utilizes a metal seal so as to avoid deterioration with time that may occur with elastomeric seals. Metal seals require a much higher force to set than elastomeric seals. Prior art running tools have employed various means to apply the downward force needed to set a packoff. Some prior art tools use rotation of the drill string to apply setting torque. It is difficult to achieve sufficient torque to generate the necessary forces for a metal packoff, because the running tool may be located more than a thousand feet below the water surface in deep water. 
     Other running tools and techniques shown in the patented art apply pressure to the annulus below the blowout preventer and the running tool. If the blowout preventer is at the surface, the amount of annulus pressure is limited, however, to the pressure rating of the riser through which the drill string extends. This pressure rating is normally not enough to set a metal packoff. 
     Higher pressure can be achieved by pumping through the drill string. However, this requires a running tool with some type of ports that are opened and closed from the surface. This is necessary because cement must first be pumped down the drill string. The ports may be open and closed by dropping a ball or dart. A considerable amount of time, however, is required for the ball to reach the seat. Rig time is quite expensive. Another method employs raising and lowering the drill pipe and rotating in various manners to engage and disengage J-slots to open and close ports. This has a disadvantage of the pins for the J-slots wearing and not engaging properly. 
     As previously indicated, often times a portion of drill pipe must be sealed in order to pressurize the volume of pipe above the seal. In many instances an object such as a ball, a dart, or a plug, is dropped down the drill pipe to create a seal which isolates the area above the object, allowing it to be pressurized. In order to create a seal, there must be a surface within the drill pipe for the object to land on and seal against. The seal is then deactivated by over-pressurizing, which can burst a rupture disc, break shear pins, or extrude metal. Alternatively, the object can be retrieved on a wire line. In other instances, a plug may be preinstalled prior to running the tool. However, in this instance, once the drill pipe has been pressurized, the plug must be deactivated as previously discussed. The dropping and retrieval of the sealing object is time consuming and often proves to be unreliable and inconsistent. 
     A need exists for a technique that addresses the effective and efficient activation and deactivation of a seal for isolating and pressurizing a section of drill pipe. The following technique may solve one or more of these problems. 
     SUMMARY OF THE INVENTION 
     In an embodiment of the present technique, a valve, such as a ball valve is assembled and carried by a running tool. The valve is actuated by an actuator that is triggered by the running tool, and thus opens and closes communication between the drill pipe and the volume below the running tool depending upon the position of the actuator. An actuating cam is assembled below the running tool and interfaces the actuator. The actuating cam is threaded such that it travels axially relative to the stem as the stem is rotated. A profile on the actuating cam is timed with the function of the running tool and controls the action of the actuator such that the valve is open when the running tool function requires communication with the volume below the running tool and closed when the running tool needs to be pressurized. 
     In an alternate embodiment of the present technique, a valve, such as a ball valve is assembled and carried by a running tool. The valve is actuated by an actuator that is triggered by the running tool, and thus opens and closes communication between the drill pipe and the volume below the running tool. An actuating cam is assembled as part of the running tool and interfaces the actuator. The actuating cam is connected to the running tool body and is free to rotate but does not move axially. The running tool stem is threaded to the body such that it travels axially relative to the body as the stem is rotated. A profile on the actuating cam is timed with the function of the running tool and controls the action of the actuator such that the valve is open when the running tool function requires communication with the volume below the running tool and closed when the running tool needs to be pressurized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a running tool with a valve assembly constructed in accordance with the present technique. 
         FIG. 2  is an enlarged sectional view of a portion of  FIG. 1 . 
         FIG. 3  is an isolated side view of the running tool of  FIG. 1 . 
         FIG. 4  is a perspective view of the running tool of  FIG. 3 . 
         FIG. 5  is an isolated and enlarged view of the valve actuator as the valve is actuated. 
         FIG. 6  is an enlarged sectional view of a running tool with a valve assembly constructed in according with an alternate embodiment of the present technique. 
         FIG. 7  is an isolated side view similar to  FIG. 4 , but showing an alternate embodiment valve assembly. 
         FIG. 8  is a perspective view of the running tool of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , there is generally shown an embodiment for a running tool  11  that is used to remotely operate a drill pipe valve assembly  12  in conjunction with setting and internally testing a casing hanger packoff. In this particular embodiment, running tool  11  is a two-port casing hanger running tool. However, remotely operated drill pipe valve assembly  12  is not limited to this embodiment and may be employed with other running tool designs such as single or no port running tools. The running tool  11  is comprised of a stem  13 . Stem  13  is a tubular member with an axial passage  14  extending therethrough. Stem  13  connects on its upper end to a string of drill pipe (not shown) and the drill pipe valve assembly  12  at the lower end. Stem  13  has an upper stem port  15  and a lower stem port  17  positioned in and extending therethrough that allow fluid communication between the exterior and axial passage  14  of the stem  13 . 
     An inner cam  18  is a sleeve connected to and substantially surrounding stem  13 . In this embodiment, inner cam  18  has axially extending slots (not shown) along portions of its inner diameter. Keys (not shown) extend radially from outer diameter portions of the stem  13  and are captured in the axially extending slots (not shown) on the inner diameter portions of the inner cam  18 , such that the stem  13  and the inner cam  18  rotate in unison. The axially extending slots (not shown) allow the inner cam  18  to move axially relative to the stem  13 . Portions of the outer diameter of the inner cam  18  have threads (not shown) contained therein. Inner cam  18  has an upper inner cam port  19  and a lower inner cam port  21  positioned in and extending therethrough that allow fluid communication between the exterior and interior of the inner cam  18 . The inner cam  18  has an upper cam portion  23  and a lower cam portion  25 . The lower cam portion  25  has a generally uniform outer diameter, except for an upwardly facing annular shoulder  27  on the outer surface of inner cam  18 . A recessed pocket  29  is positioned in the outer surface of the inner cam  18  at a select distance below the upwardly facing shoulder  27 . 
     A body  31  substantially surrounds portions of inner cam  18  and tool stem  13 . In this embodiment, the body  31  has threads (not shown) along portions of the inner diameter of the body  31  that threadably engage the threads (not shown) on portions of the outer diameter of the inner cam  18 , such that the inner cam  18  can rotate relative to the body  31 . A lower portion of body  31  houses an engaging element  33 . In this particular embodiment, engaging element  33  is a plurality of dogs, each having a smooth inner surface and a contoured outer surface. The contoured outer surface of the engaging element  33  is adapted to engage a complimentary contoured surface on the inner surface of a casing hanger  34  when the engagement element  33  is engaged with the casing hanger  34 . The inner surface of the engaging element  33  is initially in contact with an outer surface portion of the inner cam  18 . 
     The body  31 , cam  18 , and stem  13  are connected in such a manner that rotation of the stem  13  in a first direction relative to body  31  causes the inner cam  18  to rotate in unison and simultaneously move axially upward relative to body  31 . A bearing cap  35  is securely connected to a lower portion of body  31  and substantially surrounds portions of inner cam  18  and stem  13 . The bearing cap  35  is an integral part of body  31  and as such, stem  13  also rotates relative to bearing cap  35 . Portions of the inner diameter of the bearing cap  35  have threads  36  contained therein. An actuating sleeve or cam  37  is connected to the lower end of the bearing cap. In this embodiment, portions of the outer diameter of the actuating cam  37  have threads  38  contained therein. Threads  36  in the inner diameter of bearing cap  35  are in engagement with threads  38  on the outer diameter of the actuating cam  37 . When actuating cam  37  is rotated relative to bearing cap  35 , cam  37  moves axially relative to bearing cap because of threads  36 ,  38 . 
     A piston  41  surrounds the stem  13  and substantial portions of the inner cam  18  and body  31 . Piston  41  is an exterior sleeve and is initially in a “cocked” position relative to stem  13  as shown in  FIG. 1 . Piston  41  is connected and rotates in unison with stem  13  and is also capable of movement axially relative to stem  13 . A casing hanger packoff seal  42  is carried by the piston  41  and is positioned along the lower end portion of piston  41 . Packoff seal  42  will act to seal the casing hanger  34  to the wellhead housing when properly set. 
     Referring to  FIGS. 1 and 2 , the valve assembly is comprised of valve body  45 , ball valve element  47 , valve actuator  49 , valve seal  51 , and universal threaded connector  53 . Connector  53  may, for example, connect to a cement tool. In this particular embodiment, valve body  45  is securely connected to the lower end of stem  13  by anti-rotation keys  55  that ensure that stem  13  and valve body  45  rotate in unison. Valve body  45  is not capable of axial movement relative to stem  13  in this particular embodiment. 
     Valve body  45  is also connected to actuating cam  37  for rotating actuating cam  37 . Valve body  45  and actuating cam  37  are connected to one another by anti-rotation keys  57  ( FIG. 4 ) that ensure that valve body  45  and actuating cam  37  rotate in unison. Anti-rotation keys  57  connecting the valve body  45  and actuating cam  37  are positioned in axially extending slots  59  ( FIG. 4 ) located in the actuating cam  37 , thereby allowing actuating cam  37  to move axially relative to stem  13  and valve body  45 , as stem  13 , valve body  45 , and actuating cam  37  rotate relative to bearing cap  35 . The valve body  45  houses ball valve element  47  and actuators  49 . 
     Valve actuators  49  comprise axles or trunnions that extend radially outward from opposite sides of ball valve element  47 . Valve actuators  49  are offset circumferentially from the anti-rotation keys  57  that connect the actuating cam  37  to the valve body  45 . Referring to  FIGS. 3 and 4 , in this embodiment, each valve actuator  49  has a valve body portion  61  ( FIG. 2 ) and a cam portion  63  that extends radially outward from opposite sides of the ball valve element  47 . Cam portion  63  is cross-shaped when viewed in an end view having four slots ninety degrees apart from each other. A pair of elongated apertures  65  are located in and extend through opposite sides of actuating cam  37 . Cam portions  63  extend outward from the valve body portions  61  ( FIG. 2 ) of valve actuators  49  and extend through apertures  65  in actuating cam  37 . Apertures  65  capture the cam portions  63 . In this embodiment, actuators  49  are initially in a lower position within apertures  65 , as illustrated in  FIGS. 3 and 4 . A set of tabs  67 ,  69  are formed in the outer peripheries of apertures  65  at different elevations from the end of apertures  65 . The cam portions  63  are adapted to be rotated about their axes by contact with tabs  67 ,  69 , thereby rotating valve actuators  49  and opening or closing ball valve element  47 . One tab  67  is on one side edge of aperture  65  and tab  69  is on the other side edge. 
     In operation, the piston  41  is initially in a “cocked” position, and the stem ports  15 ,  17  and inner cam ports  19 ,  21  are offset from one another as shown in  FIG. 1 . A casing hanger packoff seal  42  is carried by the piston  41 . The ball valve element  47  is initially in the open position to allow for through pipe operations such as cementing strings into place. In the open position, ball valve element  47  has the same diameter as passage  14  in stem  13 . The running tool  11  is lowered into casing hanger  34  until the outer surface of the body  31  of running tool  11  slidingly engages the inner surface of the casing hanger  34 . Casing hanger  34  will be secured to a string of casing that is supported by slips at the rig floor. Bearing cap  35  will be in contact with a shoulder or bowl in casing hanger  34 . 
     Once the bearing cap  35  of running tool  11  and the casing hanger  34  are in abutting contact with one another, the stem  13  is rotated a specified number of revolutions relative to body  31  and bearing cap  35 . Keys  55 ,  57  ensure that as stem  13  rotates, actuating cam  37 , and valve body  45  rotate in unison and relative to bearing cap  35 . As the stem  13  is rotated relative to the body  31  and bearing cap  35 , the inner cam  18  and the actuating cam  37  move longitudinally in opposite directions relative to stem  13 . As tool stem  13  and actuating cam  37  rotate, actuating cam  37 , which is threaded to inner surface of bearing cap  35 , begins to move axially downward relative to bearing cap  35  due to engagement of threads  36 ,  38 . As the inner cam  18  moves longitudinally upward, the upwardly facing shoulder  27  on the outer surface of inner cam  18  makes contact with the engaging element  33 , forcing it radially outward and in engaging contact with a profile or recess in the inner surface of the casing hanger  34 , thereby locking body  31  to the casing hanger  34 . As inner cam  18  moves longitudinally upward, stem ports  15 ,  17  and inner cam ports  19 ,  21  also move relative to one another. 
     Once the running tool  11  and the casing hanger  34  are locked to one another, the running tool  11  and the casing hanger  34  are lowered down the riser (not shown) until the casing hanger  34  comes to rest in a subsea wellhead housing. The operator then pumps cement down the string, through the casing and back up an annulus surrounding the casing. The operator then prepares to set the packoff seal  42 . 
     In order to activate the piston  41  and set the packoff seal  42 , ball valve element  47  must be closed. The stem  13  is then rotated a specified number of additional revolutions in the same direction as before. As the stem  13  is rotated relative to the body  31 , the inner cam  18  and actuating cam  37  move further longitudinally relative to stem  13 . As the inner cam  18  moves longitudinally upward, stem ports  15 ,  17  and inner cam ports  19 ,  21  also move relative to one another. Upper stem port  15  aligns with upper inner cam port  19 , allowing fluid communication from the axial passage  14  of stem  13 , through stem  13 , into and through inner cam  18 , and into chamber  70  of piston  41 . 
     Referring to  FIG. 5 , as the inner cam  18  ( FIG. 1 ) moves longitudinally upward, the actuating cam  37  simultaneously rotates in unison with the stem  13  and also moves longitudinally downward because bearing cap  35  is held stationary with body  31 . Stem  13  and valve body  45  do not move upward or downward during this rotation. The anti rotation keys  57  connecting the actuating cam  37  to the valve body  45  move longitudinally down in the slots  59  in actuating cam  37  as actuating cam  37  moves downward relative to valve body  45  as they both rotate. As stem  13  rotates, actuating cam  37  continues to move axially downward relative to valve body  45  and away from bearing cap  35 . As actuating cam  37  moves axially downward, the position of cam portions  63  of valve actuators  49  change within slots  65 . The stem  13 , valve body  45 , and actuating cam  37  continue to rotate, and actuating cam  37  moves axially downward relative to actuators  49  until tabs  67  make contact with the cam portions  63  of valve actuators  49 , causing actuators  49  to rotate in a first direction as actuating cam  37  continues downward. As valve actuators  49  rotate, ball valve  47  simultaneously rotates to a closed position, thereby sealing the lower end of stem  13 . 
     The operator stops rotating stem  13  at this point. Fluid pressure is then applied down the drill pipe and travels through the axial passage  14  of stem  13  before passing through upper stem port  15 , upper inner cam port  19 , and into chamber  70  of piston  41 , driving it downward relative to the stem  13 . As the piston  41  moves downward, the packoff seal  42  is set. 
     Once the piston  41  is driven downward and the packoff seal  42  is set, the stem  13  is then rotated an additional specified number of revolutions in the same direction as before. As the stem  13  is rotated relative to the body  31 , the inner cam  18  and actuating cam  37  move further longitudinally in opposite directions relative to one another. As the inner cam  18  moves longitudinally upward, stem ports  15 ,  17  and inner cam ports  19 ,  21  also move relative to one another. Lower stem port  17  aligns with lower inner cam port  21 , allowing fluid communication from the axial passage  14  of stem  13 , through stem  13 , into and through inner cam  18 , and into an isolated volume above the packoff seal. Although the actuating cam  37  also continues to travel longitudinally downward, the ball valve element  47  remains closed because actuator  49  and cam portion  63  is still below tab  69 . The operator stops rotating stem  13  for this test portion. Pressure is applied down the drill pipe and travels through the axial passage  14  of stem  13  before passing through lower stem port  17 , lower inner cam port  21 , and into an isolated volume above the packoff seal  42 , thereby testing the packoff seal  42 . A seal (not shown) on the outer diameter of the piston  41  seals against the bore of the wellhead housing (not shown) to define the test chamber. 
     Referring to  FIG. 4 , once the packoff seal has been tested, the stem  13  is then rotated a specified number of additional revolutions in the same direction. As the stem  13  is rotated relative to the body  31  and bearing cap  35 , the inner cam  18  and the actuating cam  37  move further longitudinally apart from each other. As the inner cam  18  moves longitudinally upward, the engagement element  33  is freed and moves radially inward into recessed pocket  29  on the outer surface of inner cam  18 , thereby unlocking the body  31  from the casing hanger  34 . Because of threads  36 ,  38  the actuating cam  37  moves further longitudinally downward relative to the actuator  49  until upper tab  69  makes contact with the cam portions  63  of actuators  49 . This engagement causes actuators  49  and the ball valve element  47  to rotate in a second direction, which is opposite from the earlier rotation, thereby opening the ball valve element  47 . The open ball valve element  47  will vent the column of fluid in the drill pipe, allowing dry retrieval of the running tool  11 . Running tool  11  can then be removed from the wellbore. 
     Referring to  FIGS. 6 ,  7 , and  8 , in an alternate embodiment of the present technique, an actuating cam  71  is connected to a body  73  of a running tool  74 . The actuating cam  71  is free to rotate about the body  73 , as it is connected to the body  73  by pins or keys  75  captured in a slot  77  that extends around the outer periphery of the inner surface of the body  73 . The actuating cam  71  is restricted from axial movement relative to the body  73 , but can rotate relative to the body  73 . The running tool stem  79  is connected to a valve body  81  by anti-rotation keys  83  identical to those previously discussed in the first embodiment of the technique. In this particular embodiment, the stem  79  of the running tool rotates and also moves longitudinally relative to the body  73  to actuate an engagement element, align ports, and open and close a valve element  85  for setting and testing a packoff seal. As a result, as the stem  79  rotates, valve body  81 , and actuating cam  71  rotate in unison. As stem  79  rotates, the stem  79  and the valve body  81  also move longitudinally downward relative to actuating cam  71 . This alternate embodiment operates similar to the first embodiment of the technique, except in this embodiment, the tool stem  79  and the valve body  81  move axially downward relative to the body  73  as the stem  79  rotates, while the actuating cam  71  rotates with them but does not translate axially. 
     In operation, the cam portions  87  of actuators  89  are captured within slots  91  located in and extending through opposite sides of actuating cam  71 . In this embodiment, the cam portions  87  of actuators  89  are initially in an upper position within slots  91 . In order to actuate the valve element  85 , the stem  79  is rotated relative to the body  73 . As the stem  79  rotates relative to the body  73 , the tool stem  79  and valve body  81  rotate and move axially downward relative to body  73 . Actuating cam  71  rotates with stem  79  and valve body  81  but does not move downward relative to body  73 . As a result, the location of the cam portions  87  of actuators  89  move downward within slots  91  in relation to the axial movement of stem  79 . The stem  79  continues to rotate a specified number of revolutions, and the valve body  81  continues to simultaneously rotate and move axially downward until tabs  93  make contact with the cam portions  87  of actuators  89 , causing actuators  89  to rotate clockwise as valve body  81  continues downward. As actuators  89  rotate, the valve element  85  rotates, thereby closing the valve  85 . Continued rotation of the stem  79  will result in valve body  81  moving further axially downward relative to body  73  and actuating cam  71  until tabs  95  make contact with cam portions  87  of actuators  89 , causing actuators  89  to rotate counter-clockwise. As actuators  89  rotate, valve element  85  also rotates, thereby closing valve element  85 . 
     The remotely operated drill pipe valve is an effective and efficient technique to create a remotely operated seal in a section of drill pipe. The technique has significant advantages. An example of these advantages include efficiency as it saves time that would be spent waiting on a dart or other object to reach a landing sub or waiting on retrieval of a dart or other object, particularly in deep water. Another example is that the technique can be employed in deviated holes where gravity cannot feed a ball or dart along the entire length of drill pipe. Additionally, it is impossible for the valve to be open or closed at the wrong times or positions because the valve is timed with the tool, therefore, preventing damaging the running tool or other equipment. 
     While the invention has been shown in only one of its forms, it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes without departing from the scope of the invention. For example, although the remotely operated drill pipe valve in this embodiment has been illustrated with a two-port running tool, the remotely operated drill pipe valve can be employed with various running tool designs, such as a single port or no port running tool.