Patent Application
20100276153
This invention relates in general to subsea tools and in particular to a remotely operated drill pipe valve.
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.
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.
Referring to
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
Referring to
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 (
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
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
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
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
Referring to
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.
