The present invention relates to slip bowls for snubbing equipment and hydraulic work over units, and more particularly, to a slip bowl that can prevent oilfield tubulars used downhole from movement in both the in-hole direction and the out-of-hole direction simultaneously.
A slip bowl is used to maintain control over oilfield tubulars such as drill string, production pipe, or well bore casing as they are being introduced into or removed from a well bore. For purposes of this application, unless otherwise indicated the term “tubulars” and “oilfield tubulars” refer to drill pipe, drill strings, production pipe, production strings, jointed pipe and collars, jointed and continuous tubing, casing and other types of oilfield tubular members and strings formed of such tubular members. Slip bowls have been an integral part of the snubbing service industry for the past 50 years. Existing sizes and styles of traditional slip bowls are designed to support pipe weight in only one direction. The slip bowl operates as a mechanical check valve, allowing pipe to move freely in one direction but not in the opposite direction when the bowl is closed. Current designs require snubbing units to have a set of two slip bowls. Each set has one bowl right side up to handle pipe-heavy weight (i.e., load directed down into the well bore when the pipe weight exceeds the force from well pressure) and one bowl upside down to handle pipe-light weight (i.e., load directed out of the well bore when the force from well pressure exceeds the pipe weight). Thus, two bowls are required to hold the pipe in two directions. Additionally, traditional slip bowls are not rated to handle rotational torque loads. Thus, there is a need for a new type of slip bowl that has the capability of supporting drill pipe in both axial directions and to transmit rotational loads.
The present invention, as disclosed and described herein, in one aspect thereof comprises an omnidirectional slip bowl including a support frame having a central axis and defining an opening therein to receive an oilfield tubular passing into or coming out of a wellbore. A plurality of pivot arms move between an open configuration and a closed configuration. A plurality of cylinder mounts slidably engage the support frame and move between the open configuration and the closed configuration. Each of the plurality of cylinder mounts are associated with one of the plurality of pivot arms. A plurality of actuating mechanisms each associated with one of the plurality of pivot arms have a first end connected to one of the plurality of pivot arms and a second end connected to one of the plurality of cylinder mounts. Each of the plurality of actuating mechanisms moves the associated pivot arm and the associated cylinder mount between the open configuration and the closed configuration. A plurality of pipe inserts engage the tubular in the closed configuration to prevent the tubular from moving perpendicularly to the central axis of the support frame. A plurality of carrier plates each associated with one of the plurality of pivot arms has a first side for supporting a pipe insert of the plurality of pipe inserts and a second side defines a plurality of alternately angled surfaces. A first portion of the plurality of alternately angled surfaces are angled in a first direction and a second portion of the plurality of alternately angled surfaces are angled in a second direction. A plurality of slide plates, each of the plurality of slide plates has a first side for engaging a corresponding surface on one of the plurality of pivot arms and a second side defining a plurality of alternately angled surfaces. A first portion of the plurality of alternately angled surfaces are angled in a first direction and a second portion of the plurality of alternately angled surfaces are angled in a second direction.
When the plurality of pivot arms are in the closed configuration and the tubular is moving out of the wellbore, the slide plate moves in a first direction along the pivot arm and the first portion of the plurality of alternately angled surfaces angled in the first direction of the slide plate engage the first portion of the plurality of alternately angled surfaces angled in first direction of the carrier plate to cause the pipe insert associated with the carrier plate and the slip plate to more firmly engage the tubular to prevent moving out of the wellbore. When the plurality of pivot arms are in the closed configuration and the tubular is moving into the wellbore, the slide plate moves in a second direction along the pivot arm and the second portion of the plurality of alternately angled surfaces angled in the second direction of the slide plate engage the second portion of the plurality of alternately angled surfaces angled in the second direction of the carrier plate to cause the pipe insert associated with the carrier plate and the slip plate to more firmly engage the tubular to prevent moving into the wellbore.
For a more complete understanding, reference is now made to the following description taken in conjunction with the accompanying Drawings in which:
Referring now to the drawings, wherein like reference numbers are used herein to designate like elements throughout, the various views and embodiments of an omnidirectional slip bowl are illustrated and described, and other possible embodiments are described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated and/or simplified in places for illustrative purposes only. One of ordinary skill in the art will appreciate the many possible applications and variations based on the following examples of possible embodiments.
Referring now to the drawings, and more particularly to
The pivot arms 112 pivot between the closed position as illustrated in
The pivot arm 112 has mounted thereon a slip plate 122. When the slip bowl is in the closed configuration, the slide plate 122 moves up and down along an interior arc-shaped face of the pivot arm 112 in order to maintain engagement of the slip bowl with the tubular located within the slip bowl 102. The slide plate 122 engages a carrier 124 that moves up and down along the inner face of the pivot arm 112 in association with the slide plate 122. A gripping insert 126 is mounted within the carrier 124. The gripping insert 126 includes a surface, as will be more particularly described hereinbelow, for engaging the surface of the pipe or casing that is inserted within the slip bowl 102. The gripping insert 126 prevents the tubular from moving perpendicularly to the central axis of the support frame 104 when gripping the tubular.
Referring now to
Referring now also to
The slip plate 122 comprises an elongated member having a first side (i.e., outer face) thereof having an arcuate shape that engages with a similar arcuate shape on an interior face of the pivot arm 112. The curved shape of the outer face of the slide plate 122 and the corresponding curved shape of the inner face of the pivot arm 112 enable the slide plate to move up and down along the pivot arm 112. The arcuate shape of the slip plate 122 allows the carrier 124 to self-adjust and remain parallel to the centerline of the tubular in the wellbore. If for instance, the tubular was significantly undersized or the gripping insert worn and dull, the pivot arms 112 would travel further than nominal towards the centerline of the tubular before the insert would meet the tubular. Without the circular surface the gripping insert 126 would only contact the tubular at the insert's top edge. The circular sliding surface of the slip plate 122 allows the carrier 124 to shift with respect to the pivot arm 112 and align with the surface/centerline of the tubular. As the pivot arm 112 pivots closer to the centerline of the tubular, the slip plate 122 will remain parallel to the centerline tubular and drop down closer to the pivot of the pivot arm as it slides along the circular surface. The slip bowl cylinders 116 will position the pivot arms 112 until the gripping inserts 126 contact the tubular and the pre-load springs have been fully compressed. Then as the slip bowl is loaded, the angles on the second surface of the slip plate 122 will force the pivot arm 112 out until the hook 302 rests against the locking pin 304.
A second side (i.e., inner face) of the slide plate 122 defines a series of alternating angled surfaces 308 that are angled in a first direction 308A or a second direction 308B. By providing the alternating angled surfaces 308, the slide plate 122 allows movement of the carrier 124 and gripping insert 126 to enable the gripping insert to grip and hold a section of tubular in both of out-hole and in-hole directions. In this manner, the same group of pivot arms 112 and a single slip bowl 102 can prevent the tubular from moving in either direction in or out of the wellbore.
Referring now to
Referring now to
As further described herein, when the slip 102 is gripping the tubular in either a pipe-heavy or pipe-light configuration, the outward lateral force on the pivot arm 112 caused by the wedging action between the slide plate 122 and carrier 124 is transmitted up the pivot arm to the hook member 302, causing the hook member to likewise exert an outward lateral force against the latching bar 304. The greater the wedging force on the pivot bar 112, the greater the locking force between the hook member 302 and the latching bar 304, regardless of whether the load is from a pipe-heavy or pipe-light situation. This interlocking relationship helps ensure the latching bar 304 cannot disengage from the hook member 302 and open the slip 102 when a significant load is present.
The carrier 124 includes on an outer face 609 thereof a series of oppositely angled surfaces 610 and 612. A first portion 610 of the surfaces are angled in a first direction while a second portion 612 of the surfaces are angled in a second direction to provide a series of peaks and valleys and, when in an unloaded configuration, where the peaks of the carrier plate substantially align with the valleys of the slide plate 122 and the valleys of the carrier substantially align with the peaks of the slide plate. The oppositely angled surfaces enable the carrier 124 to configure the slip bowl 102 to engage and grip a tubular that is either being pushed down into a wellbore or pulled out of the wellbore. When the slip bowl 102 is gripping a tubular within the slip bowl and the weight of the string is pulling the pipe down into the wellbore, the first angled faces 610 of the carrier 124 are wedgingly engaged with an adjoining angled faces 608 of the slide plate 602. Similarly, when the slip bowl 102 is gripping tubular that is being forced upward out of the wellbore, the second angled surfaces 612 of the carrier 124 wedgingly engage adjoining angled surfaces 610 on the slide plate 122 to prevent movement of the tubular out of the slip bowl. The inner surface 616 of the carrier 124 includes slots 618 for receiving the gripping inserts 126 that directly engage the tubular and a pivoting member 128 to secure a gripping insert 126 into the carrier 124. The carrier 124 has extending perpendicularly from the back thereof a retaining arm 404 defining an opening 620 therein that is inserted through a slot 622 defined within the slide plate 122. As described hereinabove, when the retaining arm 404 is inserted through the slot 622 of the slide plate 602 and further through a corresponding slot 508 within the pivot arm 112, a pin may be used to insert through the pivot arm and the opening 620 to retain the carrier 124 and slide plate 122 against the pivot arm 112.
In some embodiments, the wedging surfaces on the slide plate 122 and carrier 124 each comprise at least one set of first and second flat surfaces, where each respective first flat surface is angled at a constant positive slope and each respective second flat surface is angled at a constant negative slope (with the slopes being measured relative to a median line on the respective wedging surface). In some such embodiments, multiple sets of first and second flat surfaces are arranged consecutively along the wedging surfaces (also known as “sawtooth” profile). For example, in the embodiment of
Referring now to
When the pivot arms 112 are in a closed position and the slip bowl 102 is supporting a tubular from either falling into or pushing out of a wellbore, the cylinder mount 120 locks the pivot arms in the closed position. This is more particularly illustrated in
Once there is tubular string weight held by the slip bowl 102, the tubular weight may in one embodiment provide a downward force in the direction shown by arrow 802. The downward force 802 of the tubular weight forces the carriers 124 to move downward relative to the slide plates 122 causing the adjoining angled surfaces to wedge against one another and produce an outward lateral force on the slide plates 122 shown by arrow 804. This causes the slide plate 122 to provide a lateral force on the pivot arms 112 in the direction illustrated by arrows 804. The lateral force 804 upon the pivot arm 112 also causes a lateral force between the hook 302 at the top of the pivot arm 112 and the latching bar 304 as illustrated generally by the arrows 806. The lateral force causes frictional forces between the hook 302 and latching bar 304 to help lock the latching bar in place and keep the cylinders 116 from being able to unlatch the pivot arms 112 when tubular weight is present in either direction.
It will be appreciated by those skilled in the art having the benefit of this disclosure that this omnidirectional slip bowl provides a single slip bowl for supporting tubular weight either down into or out of the drill hole. It should be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to be limiting to the particular forms and examples disclosed. On the contrary, included are any further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments apparent to those of ordinary skill in the art, without departing from the spirit and scope hereof, as defined by the following claims. Thus, it is intended that the following claims be interpreted to embrace all such further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments.