Patent Application
20090121507
The present invention relates to an apparatus for gripping a down hole tubular, and in particular, an apparatus for gripping a down hole tubular for use in a drilling machine.
It is known to grip a down hole tubular, such as drill pipes and casing, for use in oil well drilling machines. In some situations, the device is designed to grip the tubular around the upper end thereof and rotate the down hole tubular in a high speed manner. For example, a plurality of gripping members can be spaced around the periphery of the down hole tubular. In some devices, the gripping members are configured to move axially and radially into engagement with the down hole tubular. In some situations, however, the gripping members may not be moved in a completely synchronous manner, and may tend to bind up on the down hole tubular as they are engaged therewith. In addition, some devices may be configured with latches or other systems that can become loosened or disconnected during operation, or can be difficult to manipulate.
The present invention is defined by the following claims, and nothing in this section should be considered to be a limitation on those claims.
In one embodiment, the apparatus for gripping a down hole tubular includes a body element defining a central cavity along a longitudinal axis. Disposed within the body element is at least one engaging member having an upper gripping element and a lower gripping element. The gripping elements are designed to be movable with respect to one another. A rod is pivotally attached to the engaging member. The rod moves the engaging member linearly and radially inward or outward with respect to the longitudinal axis of the central cavity.
In one embodiment, the engaging member includes a guide that is disposed in a track located within the body element to facilitate the radial and linear movement discussed above. One of the lower and upper gripping elements of the engaging member are pivotally connected to a second end of the rod. A biasing member biases the other of the lower and upper gripping elements into engagement with the tubular. In another embodiment, the rod is connected to the upper gripping element, while in another embodiment the rod is connected to the lower gripping element.
In another aspect, an apparatus for gripping a down hole tubular for support and rotation includes a body element defining a central cavity having a longitudinal axis. A slewing device is coupled to one end of the body element. The slewing device is moveable with respect to the body element along the longitudinal axis. A first end of a rod is slidably and rotatably connected to the slewing device, such that the first end is radially moveable relative to the longitudinal axis as the slewing device is moved along the longitudinal axis from a first position to a second position. An engaging member is pivotally connected to a second end of the rod.
In another aspect, a method for gripping a down hole tubular includes inserting the down hole tubular within a body element. At least one rod is lowered via a stewing device such that at least one engaging member engages the down hole tubular. During the engagement of the down hole tubular, an upper gripping element and a lower element of the engaging member are displaced with respect to each other to firmly engage and align the down hole tubular. Upon engagement of the down hole tubular, additional operational steps may be performed, such as rotation of the down hole tubular for make-up/break-out operations. Upon completion of such operational steps, the rod is raised via the slewing device, thereby disengaging the gripping element from the down hole tubular. Finally, the lifting/rotating tool is removed from the down hole tubular.
In one embodiment, the method may further include biasing the upper gripping member towards or away from the lower gripping member during the engagement process of the down hole tubular. The biasing of the upper or lower gripping member allows for further engagement with the down hole tubular.
The various embodiments provide significant advantages over other down hole tubular gripping devices. For example and without limitation, the slidable and rotatable connection of the rod with the slewing device provides for the gripping members to be synchronously engaged with the down hole tubular. At the same time, the rods are secured to the slewing device, and do not require any latch devices. Furthermore, the two-piece gripping element allows for the gripping device to engage irregular-shaped down hole tubulars. The biasing element provides for the gripping members to be brought into further engagement with the down hole tubular. The biasing element further provides for the self-alignment of the down hole tubular during the engagement process and eliminates the requirement for an additional alignment mechanism.
The foregoing paragraphs have been provided by way of a general introduction, and are not intended to limit the scope of the following claims. The various embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.
Referring to the drawings,
Further attached to the slewing device 30, and in particular the lower component 33, are a series of rods 40, having first 42 and second ends 44, where the second end 44 of the rod 40 is disposed within a body element 50 defining the longitudinal axis 52. It can be appreciated that the lifting/rotating tool 10 may be operated in different orientations. The first ends 42 of the rods 40 are radially moveable relative to the longitudinal axis and are slidably connected within radially extending slots formed in mounting portions connected to the bottomside of the slewing device 30. In operation, the slewing device is moved from the first position 34 to the second position 36, such that the rods 40 are moved from a first position 46 to a second position 48. During this operation, the first end 42 of the rod 40 is displaced to a position closer to the longitudinal axis 52. It can be appreciated that the ability of the rod 40 to be radially moveable with respect to the longitudinal axis 52 and the slewing device 30 eliminates the need for the rod 40 to be configured with two or more linked members to accommodate for the radial displacement of the rod 40 during the engagement process with the down hole tubular 20.
In addition, the change of position of the first end 42 of the rod 40 allows for the accommodation of the varying sizes and irregularities of the down hole tubulars 20, such that engaging members 58 pivotally coupled to the second end 44 of the rod 40 can be synchronously engaged with the down hole tubular 20. The second end 44 of the rod 40 pivotally coupled to the engaging member 58 also is disposed within the body element 50. Various embodiments include three or four rods, though other numbers may be provided.
The body element 50 also defines an opening 60 along its longitudinal axis 52 to allow a portion of the quill 18 or the adapter 54 to pass therethrough to engage the down hole tubular 20. Often, an in-line blow out preventer (not shown) and one or more saver subs (not shown) will be disposed between the upper end of the body element 50 and the quill 18. The body element 50 defines a central cavity 62 that allows for the insertion of the down hole tubular 20. The inner diameter of the central cavity 62 may decrease as it approaches the bottom of the body element 50. The body element 50 includes in one embodiment an upper housing bell component 35 and a lower housing bowl component 37 joined with a belt clamp 39, which locks the bowl to the bell.
As best shown in
The engaging member 58 defines an engaging portion 74 that is designed to engage the down hole tubular 20. The engaging portion 74 comprises a portion of the upper gripping element 64 and lower gripping element 66. The engaging portions 74 of the elements 64, 66 should be aligned with each other so as to provide full surface support when the gripping elements 64, 66 are moved with respect to each other during the engagement process. In one embodiment, the engaging portion 74 of the engaging member 58 defines a surface having a shape similar to the down hole tubular 20. For example, if the shape of the down hole tubular 20 is cylindrical, the engaging portions 74 should have a inner semi-circular shape, or concave surface, to maximize the surface area in contact between the engaging member 58 and the down hole tubular 20 when in the engaged position. Additionally, the engaging portion 74 of the engaging member 58 may also have a gripping surface 76 to increase the frictional force between the engaging member 58 and down hole tubular 20 during operation. The gripping surface 76 may consist of horizontal lines, vertical lines, a knurled pattern, or any other pattern and/or combinations thereof. It will be appreciated that the semi-circular shape of the engaging member 58 may also aid in centering the down hole tubular 20 during the engagement process. The centering of the down hole tubular 20 is achieved as the gripping elements 64, 66 simultaneously and synchronously downwardly converge toward the longitudinal axis 52, thereby aligning the down hole tubular 20 with the longitudinal axis 52.
In one embodiment, the lower gripping element 66 is pivotally coupled to the second end 44 of the rod 40. The rod 40 can have a cylindrically shaped cross-section, a rectangular cross-section, or another shape or combination thereof. The upper gripping element 64 defines a channel or opening 78 through which the rod 40 passes such that it can be connected to the lower gripping element 66. The upper gripping element 64 and lower gripping element 66 may be of complimentary shapes to allow the two elements to fit together, as shown in
Disposed above the upper gripping element 64 is a biasing element 80 which biases the lower gripping element 66 towards the upper gripping element 64 when the gripping elements are not engaged with a tubular 20. As the rods push the lower gripping element 66 downwardly away from the upper gripping element 64, which engages the tubular 20 first, the biasing element further exerts a biasing force against the upper gripping element 64 towards the second end 44 of the rod 40 during the engagement process. Although the upper gripping element 64 and the lower gripping element 66 may not be linked together, or the rod 40 and the upper gripping element 64 linked together, the position of the upper gripping element 64 is dependent on the position of the lower gripping element 66 as a result of the biasing element 80 and the rod 40. The biasing element 80 may consist of a tension spring, a compression or torsion spring, a cantilever spring, an elastic sleeve, and/or some combination thereof. The biasing element 80 is disposed on the rod 40, with a top end of the biasing element engaging a shoulder 41 formed on the rod. A bottom end of the biasing element engages a housing or collar 82 secured to and extending upwardly from the upper gripping element 64, with the biasing element disposed in the housing/collar 82. Alternatively, the biasing element 80 may be disposed within the rod 40. In the latter embodiment, the rod 40 has a hollow portion (not shown) adapted to house the biasing element 80.
In operation, the rods 40 move downwardly and inwardly, with the collar 82 compressing the biasing element 80, which in turn exerts a force against the upper gripping element 64 towards the second end 44 of the rod 40 and into engagement with the tubular 20. Such a design helps prevent debris from the drilling operation to clog or impede the biasing function of the biasing element 80. Regardless of its location, the biasing element 80 aids the upper gripping element 64 to engage the down hole tubular 20. It can be appreciated that the biasing element 80 also aids the upper gripping element 64 to center the down hole tubular 20 with the longitudinal axis 52 during operation. The downward and inward movement of the rod also engages the lower gripping element 66 with the tubular 20. In this embodiment, the upper and lower gripping elements 64, 66 move away from each other as they are brought into engagement with the tubular 20.
In another embodiment, as shown in
In this embodiment, the biasing element 80 biases the lower gripping element 66 away from the second end 44 of the rod 40 and the upper gripping element 64, for example when the gripping elements are in a disengaged position. Again, it can be appreciated that the biasing element 80 can consist of a spring (compression, tension, torsion, leaf, etc.), an elastic material, and/or combinations thereof. Alternatively, the biasing element 80 may be incorporated into the lower portion 84 of the upper gripping element 64 or an inner portion (not shown) of the lower gripping element 66. Such a configuration will prevent debris and foreign material produced from the drilling operation to impede the functionality of the biasing element 80. As the rod 40 is moved downwardly and inwardly the lower gripping element 66 is first engaged with the tubular 20, by way of the biasing force of the biasing element, with the upper gripping element then being brought into engagement with the tubular 20. In this embodiment, the gripping elements are moved toward each other as they are brought into engagement with the tubular 20.
In operation, the lifting/rotating tool 10 can be used both to lift and to rotate the down hole tubular 20 by first positioning the lifting/rotating tool 10 over the down hole tubular 20 and positioning the engaging members 58 in a non-engaging position, as shown in
Once the lifting/rotating tool 10 is in the proper position, the slewing device 30 is then lowered by the at least one hydraulic cylinder 28, which in turn lowers the series of rods 40 and engaging members 58. The first end 42 of the rods 40 are radially and slidably displaced to a position closer to the longitudinal axis 52 of the body element 50, thereby allowing the engaging members 58 to move axially downwardly and radially inwardly to engage the down hole tubular 20. For example as shown in
As the hydraulic cylinders 28, or other actuators, are extended, the engaging members 58 are progressively moved radially inwardly, along the track 70 disposed within the liner 72, until the upper gripping element 64 comes into contact with the down hole tubular 20. As the rod continues to move downwardly, the lower gripping element 66 is brought into engagement with the down hole tubular 20. When the lower gripping element 66 is fully engaged with the down hole tubular 20, the biasing element 80 is compressed and exerts a force against the upper gripping element 64 towards the second end of the rod 44. The biasing element 80 performs at least two functions. First, if necessary, the biasing element 80 displaces the upper gripping element 64 radially inwardly towards the central cavity 62 of the body element 50, thereby further engaging the down hole tubular 20. Second, the biasing element 80 allows the upper gripping element 64 to align the down hole tubular 20 with the longitudinal axis 52.
Once the engaging members 58 fully engage the down hole tubular 20, as shown in
Once the make-up/break-out operations are completed, the hydraulic cylinders 28 are actuated to raise the engaging members 58 via the rods 40. The lifting/rotating tool 10 is then removed from the down hole tubular 20, and may repeat the process with the next down hole tubular (not shown).
In another embodiment, as shown in
Alternative to the down hole tubular 20 as shown in
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.
