NONE
1. Field of the Invention
The present invention pertains to a fluid-conducting swivel assembly that permits high speed rotation without damaging fluid pressure sealing elements. More particularly, the present invention pertains to a fluid conducting swivel assembly having high tensile strength that can support both high axial string loading, as well as substantial torque loading.
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, as well as other down hole well operations, generally have about the same cost-effect as drilling rate. The present invention addresses an increase in efficiency and efficacy of such operations (and a resulting decrease in costs associated with such operations) without sacrificing safety concerns.
During down hole operations in a well, casing, drill pipe and other tubular goods are typically inserted into a pre-drilled well bore in a number of separate sections of substantially equal length commonly referred to as “joints.” The joints, which generally include threaded connections on each end, are typically joined end-to-end at the earth's surface (typically from a drilling rig) in order to form a substantially continuous “string” of pipe that reaches downward into a well.
During a pipe installation process, additional sections of pipe are added to the upper end of the pipe string at the surface 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 tubular goods 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.
Similarly, during the pipe removal or “pulling” process, sections of pipe are removed from the upper end of the pipe string at the surface in order to decrease the overall length of the pipe string in a well bore. The removal of pipe sections at the surface is repeated until a desired length of pipe has been removed from the well. The rate of removal of tubular goods from a well can amount to many hours of total work time which, in turn, equates to higher costs. As such, time reduction in pipe string removal operations can also result in significant cost savings.
In many instances, a swivel assembly is utilized as part of a rig's equipment configuration in order to facilitate pipe installation and/or removal operations; although placement can vary, in many cases a swivel assembly is installed below a rig's top drive unit to allow for remote powering of tools or equipment situated below said top drive unit. In this regard, a swivel assembly is generally used to supply control fluid (such as pressurized hydraulic or pneumatic fluid) through said swivel assembly in order to actuate tools or equipment situated below said swivel assembly, while permitting rotation of such tools or equipment below said swivel assembly. Such equipment can include, without limitation, an attached pipe string, which can be extremely heavy resulting in significant axial loading on said swivel assembly.
In order to accommodate such rotation, conventional swivel assemblies typically utilize fluid pressure sealing elements. However, a significant and persistent problem encountered with conventional swivel assemblies involves pressurization of such sealing elements within such swivel assembly, thereby creating frictional resistance to rotation. Such frictional resistance to rotation, often referred to as a “PV” factor, comprises a ratio of differential pressure to rotational speed; the higher the differential pressures across a pressure sealing element, the lower the safe limit of rotational speed. As such, frictional resistance limits the overall rotational speed of such fluid conducting swivel assemblies, thereby preventing full utilization of top drive rotational speeds. Such limitation can adversely affect drilling, pipe installation and removal, as well as other down hole operations.
Thus, there is a need for a fluid conducting swivel assembly that permits transmission of pressurized control fluid through said swivel, while protecting the integrity of fluid pressure sealing members. The fluid conducting swivel of the present invention should have sufficient strength to accommodate high axial loading and torque forces while permitting high speed rotation, all without jeopardizing the integrity of pressure sealing elements.
In the preferred embodiment, the fluid conducting swivel assembly of the present invention comprises an outer swivel body having a central through bore. A swivel hub member is rotatably disposed within the central bore of said outer swivel body. A central mandrel is connected to said swivel hub member, and can be equipped with a quick release pin-end threaded connection on one end (for example, for quick and efficient connection to a top drive quill) and a quick release box-end connection on the other end (for example, for quick and efficient connection to a casing running tool, cement head or other equipment).
Said outer swivel body has at least one channel extending through said outer swivel body, while said swivel hub member provides a base for bearings to be mounted and has at least one channel extending there through. Pressurized control fluid can be directed through said channels of swivel body member and swivel hub member to a swivel base member that serves as a fluid distribution sub; said swivel base member can include at least one valve element used to facilitate different functions below said swivel assembly.
In one embodiment, said at least one valve element could comprise a pilot operated check valve that would allow an actuator, or a plurality of actuators, to be functioned in one direction, locking said actuators in place until a signal is sent to release pressure. In another embodiment, the distribution sub of the present invention provides for use of at least one pressure limiting valve, whether or not in combination with at least one check valve, to provide a limited force from an actuator when it is functioned.
The swivel assembly of the present invention effectively eliminates a significant PV effect by allowing fluid pressure seals of said swivel assembly to be energized only when fluid pressure is required to perform a particular action. Once said action is completed, said fluid pressure seals can be de-energized, such that said seals do not contact said swivel hub, eliminating frictional contact between said seals and said central swivel hub. As a result of this reduction (or outright elimination) of a PV effect, said swivel assembly does not act as a limiting factor for rotation by a top drive unit or other equipment. By way of illustration, but not limitation, a top drive unit situated above said swivel assembly can rotate drill pipe or other equipment situated below said swivel assembly at full speed without limitation by frictional forces generated by said swivel assembly.
The swivel assembly of the present invention allows for valves that lock, reduce, and/or relieve fluid to be located on the rotating portion (i.e., downstream side) of said swivel fluid pressure sealing elements. Further, placing all functioning motor(s) or actuator(s) downstream of such swivel fluid pressure sealing elements, instead of before said sealing elements, it is possible to operate said motor(s) or actuator(s) using impulse power, and then allowing fluid pressure to be taken off swivel assembly seals after such operation has been fulfilled. 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.
Equipment and/or drill stem elements that can be remotely operated can include, but are not limited to, rotary actuators used to open or close valves, cylinders used to set or release slips (such as in a casing running tool), and or powering actuators in a cementing head in order to release darts, balls, plugs and the like.
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.
In a preferred embodiment, swivel body member 20 has a central through bore that extends through said swivel body member 20 and defines bore inner surface 21. Swivel hub member 10 and, more particularly, upright tubular sleeve member 11 thereof, is rotatably disposed within said central through bore of said swivel body member 20.
Central mandrel 30 extends through the central through bore of swivel hub member 10, and is connected to swivel base member 40. Said central mandrel 30 has a central axially aligned through bore 34 defining bore inner surface 31. Said bore 34 can serve as a flow bore for well fluids (such as, for example, drilling mud or drilling fluids) to pass through fluid conducting swivel assembly 100. For example, fluids can be pumped through a top drive unit and pass through said bore 34 into equipment or pipe situated below fluid conducting swivel assembly 100, or vice versa.
Central mandrel 30 can be beneficially equipped with quick release pin-end (male) threaded connection 32 at its upper end to permit quick and efficient connection to a top drive quill, as well as quick release box-end (female) connection 33 at its bottom end to permit quick and efficient connection to a casing running tool, cement head or other equipment.
Swivel base member 40 provides a housing for valves 41. In a preferred embodiment, said valves 41 comprise pilot operated check valves that allow an actuator, or a plurality of actuators, to be functioned or operated as more fully described below. Said actuator(s) can be functioned in a single direction, effectively locking said actuator(s) in place until a subsequent signal is sent to again function or operate said actuator(s). In another embodiment, swivel base member 40 allows for use of at least one pressure limiting valve, whether or not in combination with at least one check valve, to provide a limited force from at least one actuator when said actuator is functioned.
Still referring to
When pressurized fluid is directed in a port 22 through conduit 23, fluid pressure sealing element 60 within said swivel assembly becomes energized and expands. (As used herein the term “pressurized” means a desired elevated pressure, which is typically greater than atmospheric or ambient pressure in the vicinity of said swivel assembly). When energized, said sealing element 60 contacts the outer surface of tubular sleeve member 11 thereby creating a fluid pressure seal between said swivel body member 20 and swivel hub member 10. However, such energized sealing element(s) 60 also create frictional resistance to rotation between said swivel body member 20 and swivel hub member 10; as noted above, the higher the differential pressures across fluid pressure sealing element 60, the lower the safe and effective limit of rotational speed between swivel body member 20 and swivel hub member 10.
Referring back to
Fluid conducting swivel assembly 100 of the present invention permits communication of fluid from a control fluid supply/reservoir to fluid driven equipment used to power actuators, motors and/or other devices. As used herein, the term “fluid” is defined broadly to include any substance, such as a liquid or gas, that is capable of flowing and that changes its shape at a steady rate when acted upon by a force tending to change its shape.
Still referring to
Such control fluid passes from a recessed groove 14 through an internal channel 15 within swivel hub member 10, and is directed through a channel or flow conduit in swivel base member (not depicted in
Once a particular action or operation has been performed as desired, said valve 41 can be closed, thereby isolating control fluid from said swivel assembly and trapping control fluid pressure downstream of said valve 41. Pressure can then be relieved from said swivel assembly 100; pressurized control fluid can then be bled off or released from swivel assembly 100 (typically through bleed-off valves 24) thereby allowing fluid pressure sealing elements 60 to de-energize or relax. Such fluid pressure sealing elements 60 can also be cooled by circulating flow of such control fluid. As a result, said fluid pressure sealing elements 60 of the swivel assembly 100 of the present invention are not exposed to elevated pressures during rotation of swivel assembly 100 of the present invention. Moreover, when relaxed said sealing elements 60 do not physically contact swivel hub 10, thereby allowing said swivel hub 10 to rotate within outer sleeve member 20 at higher speeds without generating frictional resistance or damaging said swivel sealing elements 60.
Fluid conducting swivel assembly 100 of the present invention permits transmission of control fluid under pressure through said swivel assembly 100, while protecting the integrity of fluid pressure sealing elements 60. Further, said fluid conducting swivel assembly of the present invention has sufficient strength to accommodate high axial loading and torque forces, while permitting high speed rotation without jeopardizing pressure sealing elements.
Fluid pressure sealing element 60 also has opposing seal extension members 64. Said fluid pressure sealing element 60 (including, without limitation, said seal extension member 64) can deform in response to fluid pressure. In a preferred embodiment, said fluid pressure sealing element 60 is at least partially constructed of elastomeric material, rubber, polymer and/or other sealing material exhibiting desired characteristics.
Once a desired action completed, fluid pressure sealing elements of fluid power swivel assembly 100 can be selectively de-energized or relaxed, such that said sealing elements are not in physical contact with a swivel hub of fluid conducting swivel assembly 100, thereby eliminating frictional resistance to rotation caused by said sealing elements. As a result of this reduction (or outright elimination) of a PV effect, swivel assembly 100 does not act as a limiting factor for rotation by a top drive unit or other equipment. By way of illustration, but not limitation, a top drive unit 400 situated above said swivel assembly 100 can rotate pipe joint 300 or other equipment situated below said swivel assembly 100 at full speed without limitation by frictional forces generated by the seal members of said swivel assembly 100.
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.
PRIORITY OF U.S. PROVISIONAL PATENT APPLICATION Ser. No. 61/695,426, FILED Aug. 31, 2012, INCORPORATED HEREIN BY REFERENCE, IS HEREBY CLAIMED.
Number | Date | Country | |
---|---|---|---|
61695426 | Aug 2012 | US |