The present disclosure relates in general to tools or devices for gripping an outside surface of a pipe, pipe coupling, or other tubular item with large tolerances and with surface finishes typical of as-rolled steel. In particular, the disclosure relates to oilfield gripping tools, such as casing running tools, where reaction of torsional loads is required in order to operate, engage, or disengage the tool.
Mechanically-activated tools for gripping tubular articles or workpieces, such as tools described in U.S. Pat. No. 7,909,120 (Slack), can require some torque reaction in order to be activated and set. This torque reaction can be provided externally by manual or automated means separate from the primary load path and the workpiece; however, a typical method of reacting this torque is through frictional engagement with the tubular workpiece. Generally, such tools are provided with a land element (or “bumper”) that is designed to engage the exposed face of the tubular (or coupling) and which requires some applied compressive load at this interface to generate the required friction to adequately react the required torque. In many cases the activation torque required varies with setdown load, and will be dependent on how the load is reacted internally, including the diameter and nature of the internal bearing faces, friction generated by rotating seals, and incidental friction resulting from lateral loads applied to the tool.
The variability of the load reaction in some tools results in situations where generating adequate torque reaction is either difficult or impossible to achieve consistently. Such inability to react adequate torque typically occurs when the diameter of the casing (or other tubular item), and consequently the diameter at which the land element is bearing and reacting torque on the casing, is small relative to the internal bearing surfaces of the tool and associated seals. The need to supplement or enhance this torque reaction is apparent in these cases. Some means for increasing this torque are known in the art, including:
Such means have proved effective for use with some gripping tools, including internally-gripping casing running tools. However, uncertainty as to the ability to generate the required reaction has been increased by the recent development of external-gripping casing running tools having higher capacities and increased internal bearing and seal diameters relative to the casing diameter.
As such, there is a need for a mechanically-activated mechanism that will grip a pipe or coupling such that the gripping force has a mechanical advantage beyond that available with simple land element geometries reacting a generally axially-applied load on the face of the pipe or coupling. This need is especially apparent for pipe and couplings that have a limited ability to react bearing loads and torque on the exposed face, typical to some premium connections with flush or near-flush geometries.
In general terms, the present disclosure teaches a tool for gripping a tubular article or workpiece (such as but not restricted to a section or “joint” of threaded and coupled oilfield pipe) to facilitate application of torque to the tubular article. As used in this disclosure, the term “threaded and coupled pipe” is to be understood as denoting the assembly of a pipe having an externally-threaded end, onto which an internally-threaded coupling has been mounted. Embodiments of the tool are described and illustrated herein as specifically gripping the coupling of a threaded and coupled pipe assembly, and when used as such the tool may be alternatively referred to as a coupling gripper. However, such embodiments can also be used for gripping the pipe component of a threaded and coupled pipe assembly, or a plain pipe having no coupling, or for other tubular articles or workpieces.
More particularly, the present disclosure teaches a gripping tool for gripping a pipe or pipe coupling (or other tubular articles), in which the gripping tool incorporates:
Preferably (but not necessarily), the land element will have a smooth bearing face against which the end of a pipe or pipe coupling may be landed, and may be provided with radially-oriented slots or grooves to prevent the interface between the land element and a pipe face or coupling face landed against it from functioning as a seal whereby pressure may be contained in this interval or section of the assembly. The land element preferably will be attached to or incorporated into the grip element carrier such that axial load and movement applied to the land element are transmitted to the grip element carrier, thus enabling radial extension and retraction of the grip elements.
The grip elements are positioned to engage the pipe or coupling in a suitable location, taking into account the maximum anticipated grip loads, the range of possible engagement diameters, the subsequent deflection under load of the pipe or coupling, and the ability of the pipe or coupling to react the grip loads within allowable deformation limits, generally without permanent deformation or yielding. It is to be understood that the location where the grip elements engage the pipe or coupling can be at any axial position relative to the coupling face on either the inside or outside surface of either the pipe or the coupling.
The grip surfaces (i.e., the surfaces of the gripping elements that directly engage a pipe or coupling) are generally designed to minimize marking, penetration, and localized deformation. As may be desired, however, additional frictional torque reaction may be attained by providing grip-enhancing features (such as die teeth) on this surface to increase the effective friction coefficient at the interface between the grip element and the pipe or coupling.
The grip element carrier is provided with means for carrying and containing the grip elements. Such means could be provided, by way of non-limiting example, in the form of a generally cylindrical cage in which the grip elements are arranged as buttons that are radially slidable within openings or “windows” formed in the cage. In such embodiments, the buttons preferably will be in close-fitting engagement with the cage windows, and may also sealingly engage the perimeter surfaces of the cage windows. The means for carrying the grip elements may also comprise a collet arrangement wherein the grip elements are attached to a plurality of adjacent spring elements. Such spring elements would generally be arranged axially, with one end of each spring being retained and attached to the land element, and the other end attached to the grip elements.
The body element is provided with means for converting axial movement and load into radial movement and load relative to the pipe or coupling surface. Such means may comprise a cone or ramp surface that bears against the grip elements, generally opposite to the grip surfaces of the grip elements, such that radial loads from the grip surfaces are carried through the body element.
The means for reacting torque transmitted to the grip elements from the pipe or coupling may be provided by either the grip element carrier or the body element. For example, the carrier and/or the body element may be rotationally constrained to the gripping tool such that the grip elements are rotationally constrained to the carrier, constrained to the body, or frictionally engaged with the body.
The grip element retraction means may be separate from or integral with other elements of the assembly, and may be provided in a variety of alternative forms. By way of non-limiting example, the retraction means for retracting the grip elements associated with the retractor element may comprise a retractor cone engageable with mating surfaces on the grip elements when bearing loads are removed, with the retractor cone being driven by a compressive spring. The retraction means may also include radial collet springs, which can be integral with the carrier element and arranged such that the spring preload is selected to be biased in the radial direction opposite to the direction of engagement.
Embodiments in accordance with the present disclosure will now be described with reference to the accompanying figures, in which numerical references denote like parts, and in which:
Workpiece 2 is shown in
As illustrated in
Main body 30 is provided as a sub-assembly comprising an upper body 31 and bell 32, and joined at its lower end 33 by a threaded and pinned connection 34. Load adaptor 20 sealingly and rigidly connects to upper body 31 at its upper end 35 by means of a load thread 26 and a torque lock plate 27, which is keyed both to load adaptor 20 and to upper body 31, to thus structurally join load adaptor 20 to main body 30 enabling transfer of axial, torsional and perhaps bending loads as required for operation. Upper body 31 has a generally cylindrical external surface and a generally axi-symmetric internal surface carrying seal 36. Bell 32 similarly has a generally cylindrical external surface and profiled axi-symmetric internal surface characterized by a frustoconical ramp surface 37 and a lower seal housing 38 carrying a lower annular seal 39, where the taper direction of ramp surface 37 is selected so that its diameter decreases downward, thus defining an interval of the annular space 40 between main body 30 and the exterior pipe body surface 4 in which the radial thickness decreases downward.
A plurality of jaws 50, illustrated in
Cage 60, made of a suitably strong and rigid material, carries and aligns the plurality of jaws 50 within cage windows 61 provided in cage body 62, and this sub-assembly is coaxially located in annular space 40, with its interior surface generally defining interior opening 13, and with its exterior surface generally fitting with the interior profile of the main body 30.
Referring still to
A sealed upper cavity 97 is formed in an interior region bounded by load adaptor 20, upper body 31, cage 60 and stinger 90 where sliding seals 36 and 39 allow the cage to act as a piston with respect to the main body. Gas pressure introduced into sealed cavity 97 through valved port 98 therefore acts as a pre-stressed compliant spring tending to push the cage down relative to the main body.
Thus configured with the tool set, the jaws 50 act as wedges between main body 30 and workpiece 2 under application of hoisting loads, thus providing the uni-directional axial load activation typical of wedge-grip mechanisms, whereby an increase in the hoisting load tends to cause the jaws to stroke down and radially inward against the workpiece 2, thus increasing the radial gripping force exerted on workpiece 2 and enabling CRT 1 to react hoisting loads from the top drive into the casing. Gas pressure in upper cavity 97 similarly increases the radial gripping force of the jaws, tending to pre-stress the grip elements when the tool is set, and augments the gripping force produced by the hoisting load.
Cam pair 80 comprises a cage cam 81 and a body cam 82 which are generally tubular solid bodies made from suitably strong and thick material and axially aligned with each other. Cam pair 80 is located in the annular space of upper cavity 97, coaxial with and close fitting to cam housing interval 76 of cage 60. Cage cam 81 is located on and fastened to an upward-facing cam shoulder 75 on cage 60 and body cam 82 is located on and fastened to the lower end 23 of load adaptor 20.
Cam pair 80 functions to allow rotational activation in both direction and to provide a latch function that prevents setting of the tubular running tool. The cam and cam follower contact profiles, with associated angles of engagement (i.e., mechanical advantage, in both right and left hand directions, as the cam tends to climb and more generally ride on the cam follower) are thus selected according to application-specific requirements, to manipulate the relationship between applied torque and gripping force, and also to optimize secondary functions for specific applications, such as whether or not reverse torque is needed to release the tool subsequent to climbing the cam. Persons skilled in the art will appreciate that many variations in the cam and cam follower shapes can be used to generally exploit the advantages of a torque-activating grip as taught by the prior art.
The application of compressive load to load adaptor 20 by the top drive, sufficient to overcome the spring force generated by gas pressure in upper cavity 97, will be reacted externally by contact between coupling top face 9 and cage land surface 67, displacing the main body downward relative to the workpiece 2 and allowing jaws 50 to retract and draw away from the workpiece 2 thus unsetting or retracting tubular running tool 1, which position is latched by left-hand rotation of load adaptor 20 relative to workpiece 2 enabled by frictional engagement of land surface 67 on coupling top face 9, causing engagement of the latch teeth. Tubular running tool 1 is mechanically set and unset using only axial and rotational displacements, with associated forces being provided by the top drive without requiring actuation from a secondary energy source such as hydraulic or pneumatic power supplies.
Main body 280, which has an upper end 281 and a lower end 282, is generally cylindrical in shape with a radially-stepped surface profile defining an upper body carrier interval 280U and a lower body interval 280L, with the diameter of lower body interval 280L being greater than the diameter of upper body interval 260U, which defines a downward-facing internal annular shoulder 283. As best seen in
As shown in
As illustrated in
In the illustrated embodiment, grip button carrier 260 is generally cylindrical in shape and has a radially-stepped surface profile defining an upper carrier interval 260U and a lower carrier interval 260L, with the diameter of lower interval 260L being greater than the diameter of upper carrier interval 260U. In a medial region associated with the transition between upper and lower carrier intervals 260U and 260L, grip button carrier 260 defines an internal downward-facing annular shoulder 266, to which land element 240 is fixed. Grip element carrier 260 also defines an external upward-facing annular shoulder 265, associated with upper carrier interval 260U.
A plurality of windows 267 extending through the wall of lower carrier interval 260L, for receiving corresponding grip buttons 220. In the illustrated embodiment, the number of grip button windows 267 is ten, equal to the number of grip buttons 220, and they are evenly spaced around the circumference of lower carrier interval 260L. grip button windows 267 optionally have seal grooves 268 for receiving seal elements (not shown) that function to sealingly engage the lateral faces 228 of grip buttons 220 while said grip buttons are slidingly engaged in grip button windows 267.
The lower end of lower interval 260L of carrier 260 is configured to be axially slidably disposable within annular recess 150 in the uppermost region of cage 141, between cylindrical surface 152 of recess 150 and the outer cylindrical surface of the coupling 90 of a threaded and coupled pipe 85. Below grip button windows 267, lower interval 260L of carrier 260 has a seal groove 275 carrying a seal element (not shown) slidingly and sealingly engageable with the cylindrical surface 152 in annular recess 150 of cage 141.
Referring again to
Land element 240 is generally ring-shaped, with a central bore for receiving a seal assembly stinger 161 associated with grip module 140 of CRT 100. On an inside surface of its central bore, land element 240 has a seal groove 241 carrying a seal element (not shown) for sealing engagement with stinger 161. Land element 240 has an upper face 243 which abuts and is rigidly attached to downward-facing shoulder 266 of grip button carrier 260.
Referring now to
Referring again to
Referring again to
Referring now to
It is to be understood that the scope of the claims appended hereto should not be limited by the preferred embodiments described and illustrated herein, but should be given the broadest interpretation consistent with the description as a whole. It is also to be understood that the substitution of a variant of a claimed element or feature, without any substantial resultant change in functionality, will not constitute a departure from the scope of the disclosure.
In this patent document, any form of the word “comprise” is to be understood in its non-limiting sense to mean that any element following such word is included, but elements not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one such element.
Any use of any form of the terms “connect”, “engage”, “couple”, “attach”, “fix”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between the elements such as through secondary or intermediary structure.
Wherever used in this document, the terms “typical” and “typically” are to be interpreted in the sense of representative or common usage or practice, and are not to be understood as implying invariability or essentiality.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2013/000873 | 10/9/2013 | WO | 00 |
Number | Date | Country | |
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61711404 | Oct 2012 | US |