MULTI-APPLICATION CATWALK SYSTEM (MACS)

Abstract

A pipe-handling apparatus for moving a pipe relative to a drilling floor of a drilling rig, the pipe-handling apparatus having a main support structure; a pipe delivery mechanism for delivering pipe between a pipe load/unload position and a drilling floor position; and at least one walking unit comprising: a jack capable of lifting the main support structure in a substantially vertical direction; and a foot capable of moving the main support structure in a substantially horizontal direction.

Description

TECHNICAL FIELD

The present disclosure relates to catwalk systems and processes for handling drill pipe and casing relative to drill rig operations. In particular, the invention relates to catwalk systems and processes that are maneuverable and flexible to suit most applications such as multi-well pad, batch, batched section and infill drilling operations.

BACKGROUND ART

Current catwalk systems create hazardous work environments and present problems and issues during batch and infill drilling operations. Current catwalks do not provide either easy safe accessibility to the cellars or maneuverability over objects above the ground level. Unfortunately, the narrow space below known catwalks limit safe accessibility to cellars below the catwalks. Further, objects above ground level present problems for current catwalks because they are unable or have difficulty to walk or skid over the objects. Walking and skidding over objects above the ground level, e.g. live wells with caged x-trees, are difficult and hazardous tasks for most presently known catwalks. Typically, cranes must be used to lift catwalks over above-ground objects, if it is even possible for the catwalk to be positioned over or adjacent the above-ground objects. Thus, there is a need for catwalk systems and processes that accommodate above- and below-ground objects on well sites.

SUMMARY OF INVENTION

In accordance with the teachings of the present disclosure, disadvantages and problems associated with existing drill rig control systems are alleviated.

Multi-Application Catwalk System (MACS) is a comprehensive fit for purpose catwalk. MACS is designed to suit most applications such as multi-well pad, batch, batched section and infill drilling operations. Most important features of this catwalk are easy “maneuverability/flexibility” and safe “accessibility” to its beneath. MACS can be expanded horizontally and elevated vertically as desired to make feasible the operations with x-tree underneath and cellar with different sizes. Flexibility of different components of the rig is so important to allow different drilling operations under variety of circumstances. MACS will not need crane or other means of lifting to operate safely over the cellars or objects above the ground level. MACS will decrease non-productive time-NPT of the operations.

According to one aspect of the invention, there is provided a pipe-handling apparatus for moving a pipe relative to a drilling floor of a drilling rig, the pipe-handling apparatus comprising: a main support structure; a pipe delivery mechanism in mechanical communication with the main support structure for delivering pipe between a pipe load/unload position and a drilling floor position; at least one walking unit in mechanical communication with the main support structure so as to support the main support structure, wherein the at least one walking unit comprises: a jack in mechanical communication with the main support structure capable of lifting the main support structure in a substantially vertical direction; and a foot in mechanical communication with the main support structure capable of moving the main support structure in a substantially horizontal direction.

A further aspect of the invention provides a process for moving pipe relative to a drilling floor of a drilling rig, the process comprising: providing a pipe-handling apparatus to a position adjacent the drill rig; delivering pipe via the pipe-handling apparatus between a loading/unloading position and a rig floor delivery position; walking the pipe-handling apparatus from one wellbore location to another wellbore location; and reconfiguring the pipe-handling apparatus to avoid at least one obstacle during walking.

According to another aspect of the invention, there is provided a pipe-handling apparatus for moving a pipe relative to a drilling floor of a drilling rig, the pipe-handling apparatus comprising: a main support structure; a pipe delivery mechanism in mechanical communication with the main support structure for delivering pipe between a pipe load/unload position and a drilling floor position, the pipe delivery mechanism comprising a lower skate, an upper skate, a rig up system that moves the upper and lower skates between a pipe loading/unloading configuration and a pipe sliding configuration, and a pipe pusher configured to move relative to the upper and lower skates; at least one walking unit in mechanical communication with the main support structure so as to support the main support structure, wherein the at least one walking unit comprises: a jack in mechanical communication with the main support structure capable of lifting the main support structure in a substantially vertical direction; and a foot in mechanical communication with the main support structure capable of moving the main support structure in a substantially horizontal direction; a swivel in mechanical communication with the walking unit to rotate the foot around a substantially vertical axis; at least one leg in mechanical communication with the main support structure, wherein the at least one leg is extendable to raise at least a portion of the main support structure in a substantially vertical direction; and a cross brace in mechanical communication with the main support structure and the at least one leg, wherein the cross brace is extendable to extend the leg further away from the main support structure.

BRIEF DESCRIPTION OF DRAWINGS

A more complete understanding of the present embodiments may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features.

FIG. 1A is a perspective view of a catwalk having a lower skate and an upper skate configured to slide pipes, which includes casing, up and down the skates.

FIG. 1B is a perspective view of the catwalk of FIG. 1A, wherein the lower and upper skates are configured to load and unload pipes (casing) from the catwalk.

FIG. 1C is a side view of a walking unit having a jack and a foot for walking a catwalk.

FIG. 1D is a side view of a walking unit having a jack and a track for walking catwalk.

FIG. 2 is a flow chart of a process for batch drilling boreholes.

FIG. 3 is a top view of a drilling pad site for batch drilling multiple boreholes.

FIG. 4 is a perspective view of a batch of christmas trees enclosed by a cage.

FIG. 5 is a perspective view of a portion of a catwalk having legs that are extendable to raise the main support structure or frame vertically relative to the ground.

FIG. 6 is a perspective view of a portion of a catwalk and pipe feeding table.

FIG. 7 is a perspective view of a portion of a catwalk having cross braces that extend to position legs further away from the main support structure or frame of the catwalk.

The objects and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like elements.

The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments are best understood by reference to FIGS. 1A-7 below in view of the following general discussion. The present disclosure may be more easily understood in the context of a high level description of certain embodiments.

FIGS. 1A and 1B illustrate an embodiment of a catwalk of the present invention, wherein FIG. 1A shows a pipe raising configuration and FIG. 1B shows a pipe loading/unloading configuration. The catwalk 100 has an upper skate 102 and a lower skate 104. A rig-up system 108 moves the upper and a lower skates 102 and 104 between configurations, where the upper and lower skates 102 and 104 are pivotally connected to each other. A pusher 106 pushes pipe and casing up the skates to deliver pipe or casing to the drill floor level of the derrick (not shown). A pulling winch 110 facilitates movement of the pusher 106 up and down the skates 102 and 104. A frame 112 provides the foundational structure for the catwalk 100. The lower skate 104 is pivotally connected to the frame 112 at its end opposite the upper skate 104. The upper skate 104 is supported on the frame 112 via a truss 114, wherein the truss is pivotally connected at opposite ends to the frame 112 and the upper skate 104, respectively. A pipe feeding table 120 extends transversely from the frame 112 adjacent one side of the lower skate 102. On the opposite side of the lower skate 102, a casing feeding system 130 extends transversely from the frame 112. The catwalk 100 may further have legs 140 extending from the four corners of the frame 112, and each leg may have a walking unit for walking the catwalk between wellbores.

FIG. 1C shows a side view of a walking unit 140. The walking unit 140 walks by loading the weight of the catwalk on a foot, sliding the catwalk structure across the foot, transferring the weight of the catwalk from the foot to a jack, moving a foot to a new position, and repeating the steps. The walking unit 140 generally comprises a foot 141 and a jack 151. The jack 151 lifts the catwalk vertically and the foot 141 moves the catwalk horizontally. The walking unit 140 connects to a leg 116 of the catwalk 100 (see FIGS. 1A and 1B) via a leg connector 164. The swivel 162 enables the foot 141 to be pointed in any direction, 360 degrees around the jack 151, so the catwalk 100 may walk in any direction.

Regarding the jack 151, a jack inner barrel 154 connects to the leg connector 164 via a swivel 162. The jack inner barrel 154 telescopes within a jack outer barrel 152 and is moved relative thereto by a jack actuator 156. The jack actuator 156 is attached to the jack inner barrel 154 via an inner barrel anchor 158 and to the jack outer barrel 152 via an outer barrel anchor 160. A jack pad 166 is attached to the lower end of the jack outer barrel 152 for making contact with the ground. This connection is a swivel connection so the swivel 162 may rotate the foot 141 around the jack 151 when the jack 151 has lifted the foot 141 off the ground. The jack components work together to lift the catwalk 100 vertically.

Regarding the foot 141, it is for moving the catwalk in horizontal directions. A buttress 168 extends from the jack inner barrel 154 and has a foot sled 144 at its lower most end. The foot 141 has a foot pad 142 for resting on the ground and providing a broad surface area sufficient to support the weight of the catwalk 100 without sinking into the earthy material of the drilling pad site. The foot sled 144 is engaged with the upper surface of the foot pad 142 so as to slide relative thereto. A foot actuator 146 moves the foot sled 144 laterally relative to the foot pad 142. The foot actuator 146 is attached to the foot pad 142 via a pad anchor 148 and to the foot sled 144 via a sled anchor 150.

The actuators 146 and 156 may be hydraulic or pneumatic pistons, worm gears, rack and pinion gears, etc. or any movement inducing devices known to persons of skill in the art. The walking unit 140 may further comprise a control unit to coordinate movements of the jack and foot. When the catwalk has a plurality of walking units 140, the control units may be linked together for coordinated movements of the walking units 140. In particular, it is preferable that all of the walking units 140 move in the same direction at the same time, so that the catwalk 100 moves as a single unit. However, they must not always move in harmony as it may be advantageous to rotate the position of the catwalk around a vertical axis, in addition to translating the position of the catwalk in a horizontal direction.

An alternative embodiment of the walking unit 140 is shown in FIG. 5, wherein the jack 151 is configured to be between the buttress 168 and the foot 141. In this embodiment, a leg 116 extends from the frame 112 to the ground and the buttress 168 is attached to the leg 116. When the jack 151 is configured to raise the foot 141 off the ground, the leg 116 rests firmly on the ground to support the catwalk 100. When the jack is configured to lower the foot 141 to the ground and raise the buttress 168 relative to the foot 141, the leg 116 is also raised off the ground so the foot 141 may then move the catwalk in a horizontal direction (walking the catwalk).

FIG. 1D illustrates an alternative walking unit 140, wherein a foot 141 comprises a track so as to distribute the weight of the catwalk over a greater area of the ground. The track 176 is supported by a series of rollers 178 and is driven by a drive wheel 180. As shown in FIG. 1D, the foot 141 is raised off the ground as the jack 151 is extended to raise the catwalk and the foot 141 simultaneously. In alternative embodiments, the foot may comprise any locomotive device. For example, the foot may comprise wheels driven by a motor and transmission,

FIG. 2 shows a flow chart of a batch drilling process. Batch drilling is an assembly line process for drilling a cluster wells at a single pad site. The drilling rig moves between wellbores via rails, skids, or hydraulic rig walking shoes. The drilling pipe and casing stands may remain attached to the drilling rig as it moves. As shown in FIG. 2, with batch drilling, the surface section for wells A-F are drilled. The surface section of wellbore A is drilled at step 202A, and then the drill rig moves to a wellbore B and drills the surface section at step 202B. The surface sections of wellbores C, D, E and F may then be drilled in order at steps 202C, 202D, 202E and 202F. In alternative embodiments, any number of wellbores may be drilled consecutively, all with the same drilling mud, as the rig moves from wellbore to wellbore. Next, the intermediate sections of the wellbores may be drilled starting with wellbore F at step 204F. The drill rig then moves to wellbore E to drill the intermediate section at step 204E. The intermediate sections of wellbores D, C, B and A may then be drilled in order at steps 204D, 204C, 204B and 204A. Intermediate sections may all be drilled, with the same drilling mud formulated for intermediate sections, by moving the rig from wellbore to wellbore. Finally, the production section of wellbore A is drilled at step 206A, and then the drill rig moves to wellbore B and drills the production section at step 206B. The production sections of wellbores C, D, E and F may then be drilled in order at steps 206C, 206D, 206E and 206F. The production sections are typically lateral sections, wherein the laterals for the well may all be drilled, with a drilling mud formulated for laterals, by moving the rig from wellbore to wellbore.

During drilling operations, the drill rig is typically positioned directly over the wellbore with the catwalk immediately adjacent thereto. To drill a second wellbore, the drill rig typically moves in the direction of the catwalk. For example, referring to FIG. 2, when the drill rig is positioned directly over wellbore A, the catwalk is positioned over wellbores B and C. Thus, for the drill rig to move to wellbore B, the catwalk must remove itself to a position over wellbores C and D. There are no obstructions when the surface sections of the wellbores are being drilled (202A-202F). However, when the drill rig and catwalk walk back and forth over the wellbores to drill the intermediates sections (204f-204A) and the production sections (206A-206F), then the catwalk must straddle the wellbore cellars, and preferably, allow access to the cellars.

FIG. 3 shows a top view of a drilling pad site. First, second, third, fourth and fifth clusters of wellbores 301, 302, 303, 304, and 305 each have six wellbores drilled in a line, wherein the lines of each cluster are parallel but offset relative to each other. Five reserve pits 311, 312, 313, 314, and 315 may also be part of the pad site 300, wherein each reserve pit services a cluster of wells, respectively. The pad 300 may also have an entrance/exit 320, offices 330 and production facilities 330 as is well known in the art. The relative positions of the wellbores in the clusters illustrates that a catwalk may need two-dimensional walking capabilities.

FIG. 4 shows a perspective view of a cluster of well christmas trees protected by a cage. In the illustrated cluster, there are four well christmas trees. A cluster of caged christmas trees illustrates the type of above-ground obstacles over and around which a catwalk may be called upon to work for given pad site configurations.

To perform multi-well pad, batch, batched section and infill drilling, Multi-Application Catwalk System (MACS) can expand horizontally and elevated vertically safely based on desired length and height. There are many ways to build the MACS, but its most important characteristics are easy “maneuverability/flexibility” over any object on a pad and safe “accessibility” to the cellars beneath. Some of the key functionalities of MACS include: (1) being able to expands horizontally to not interfere with the cellar's diameter or width; (2) being able to adjust its height from the ground level to different elevation depending to circumstances; (3) being able to walk or skid safely over the cellars with any diameter and width and objects with different heights above the ground level; (4) being able to operate safely and easily over live wells with caged x-trees above the ground levels; (5) having simplicity to operate rather than complexity with fancy movements; (6) having horizontal pipe racking system that can be easily transformed from horizontal position to vertical position to act as elevator as height of MACS changes; (7) requiring minimal usage of fork lift, crane or other similar lifting systems; (8) being able to transported easily while rig move; (9) being able to walk and skid smoothly, precisely and safely within the pads; (10) not interfere with the v-door and rig floor space to create hazardous environment. MACS may reduce non-productive time (NPT) because there is no need to waste time to rig up and rig down the catwalk to perform safely the operations such as batch and infill drilling.

FIG. 5 shows a perspective view of a portion of a catwalk 100 that has vertically adjustable legs. A lower skate 104 is shown supported by a frame 112. Four legs 116 support the frame 112. Each leg 116 is extendable, such that a lower portion of the leg telescopes into an upper portion of the leg. An actuator is located within each leg (not shown). In this embodiment, the extendable legs adjust the height of the frame 112 relative to the ground. When the height of the frame 112 is increased, it may also be needful to adjust a casing pickup system 170 and the pipe pickup system 172. For example, MACS may have a horizontal pipe racking system that can be easily transformed to include vertical elevators 174 depending on the height of catwalk.

FIG. 6 illustrates a perspective view of a pipe feeding table adjacent a catwalk. According to some embodiments of the invention, pipe and casing tables may be elevated or lowered to the same height as the catwalk. For example, the pipe feeding table 120, which extends transversely from the frame 112 adjacent one side of the lower skate 102 (see FIGS. 1A and 1B), may be raised the same as the frame 112. Similarly, the casing feeding system 130, which extends transversely from the opposite side of the lower skate 102 (see FIGS. 1A and 1B), may be raised the same as the frame 112. These tables may be equipped with walking units to move with the catwalk.

FIG. 7 shows a perspective view of a portion of a catwalk 100 that has horizontally adjustable legs. Each leg 116 is attached to the frame 112 by a telescoping cross-brace 182. The cross-brace 182 may be lengthened or shortened to allow the leg 116 to be positioned to avoid contact with above-ground or below-ground obstructions. The length of each cross-brace 182 may be individually adjusted to allow the catwalk to flexibly conform to the particular circumstances of the working environment.

Aspects of the invention may be implemented with catwalks having a variety of pipe handling mechanisms. For example, catwalks of the present invention may comprise a pipe delivery mechanism having a pipe carrying carriage and a device for moving the carriage between a substantially horizontal position to a position having a vertical component. Examples are illustrated by U.S. Pat. Nos. 7,540,338; 8,215,887; 6,695,559; 7,163,367 and 9,476,266 the disclosures of which are incorporated herein in their entireties by reference.

It should be noted that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. In addition, the composition used/disclosed herein can also comprise some components other than those cited. In the summary of the invention and this detailed description, each numerical value should be read once as modified by the term “about” (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary of the invention and this detailed description, it should be understood that a concentration range listed or described as being useful, suitable, or the like, is intended that any and every concentration within the range, including the end points, is to be considered as having been stated. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors possessed knowledge of the entire range and all points within the range. The statements made herein merely provide information related to the present disclosure and may not constitute prior art, and may describe some embodiments illustrating the invention.

The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

If used herein, the term “substantially” is intended for construction as meaning “more so than not.”

Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Although the disclosed embodiments are described in detail in the present disclosure, it should be understood that various changes, substitutions and alterations can be made to the embodiments without departing from their spirit and scope.

INDUSTRIAL APPLICABILITY

Catwalks for drilling rigs of the of the present invention have many industrial applications including but not limited to drilling batch well bores for the oil and gas industry.

Claims

1-20. (canceled)

21. An apparatus comprising:

a catwalk comprising: a pipe delivery mechanism for moving a pipe to a drilling floor; a frame connected with the pipe delivery mechanism; a plurality of legs connected with the frame; and a plurality of walking units each comprising: a jack portion connected with a corresponding leg, wherein the jack portion comprises a jack pad configured for making contact with the ground, and wherein the jack portion is operable to move the catwalk vertically with respect to the ground; and a foot portion connected with the jack portion, wherein the foot portion comprises a foot pad configured for making contact with the ground, and wherein the foot portion is operable to move the catwalk horizontally with respect to the ground when the jack pad is not in contact with the ground.

22. The apparatus of claim 21 wherein the foot portion is directly connected with and extends from the jack portion.

23. The apparatus of claim 21 wherein the foot portion further comprises a buttress connected with and extending from the jack portion.

24. The apparatus of claim 21 wherein the catwalk further comprises a plurality of swivel connectors each connecting one of the walking units with a corresponding leg.

25. The apparatus of claim 21 wherein the jack portion comprises a vertical structural member connected with the corresponding leg, and wherein the jack pad is operable to swivel with respect to the structural member.

26. An apparatus comprising:

a catwalk comprising: a pipe delivery mechanism for moving a pipe to a drilling floor; a frame connected with the pipe delivery mechanism; and a plurality of legs connected with the frame, wherein each leg is configured to: change vertical length of the leg to change height of the frame above the ground; and move horizontally with respect to the frame to change distance between the legs on opposing sides of the frame.

27. The apparatus of claim 26 wherein each leg is configured to change vertical length and move horizontally with respect to the frame to accommodate beneath the frame a wellbore cellar and/or a Christmas tree connected over a wellbore.

28. The apparatus of claim 26 wherein each leg comprises:

a vertical telescoping portion configured to extend and retract to change the vertical length of the leg; and

a horizontal telescoping portion configured to extend and retract to move the leg horizontally with respect to the frame.

29. The apparatus of claim 26 wherein each leg comprises:

a vertical inner portion that telescopes within a vertical outer portion of the leg to change the vertical length of the leg; and

a horizontal inner portion that telescopes within a horizontal outer portion of the leg to move the leg horizontally with respect to the frame.

30. The apparatus of claim 26 wherein the catwalk further comprises a plurality of walking units each connected with a corresponding leg, wherein the walking units are collectively operable to move the catwalk horizontally along the ground, and wherein each walking unit comprises:

a jack portion operable to move the catwalk vertically with respect to the ground; and

a foot portion operable to move the catwalk horizontally with respect to the ground when the jack portion moves the catwalk vertically with respect to the ground.

31. The apparatus of claim 26 wherein the catwalk further comprises a plurality of walking units each comprising:

a jack portion connected with a corresponding leg, wherein the jack portion comprises a jack pad configured for making contact with the ground, and wherein the jack portion is operable to move the catwalk vertically with respect to the ground; and

a foot portion connected with the jack portion, wherein the foot portion comprises a foot pad configured for making contact with the ground, and wherein the foot portion is operable to move the catwalk horizontally with respect to the ground when the jack pad is not in contact with the ground.

32. The apparatus of claim 26 wherein each leg is configured for making contact with the ground, and wherein the catwalk further comprises a plurality of walking units each comprising:

a jack portion connected with a corresponding leg, wherein the jack portion is operable to move the catwalk vertically with respect to the ground; and

a foot portion connected with the jack portion, wherein the foot portion comprises a foot pad configured for making contact with the ground, and wherein the foot portion is operable to move the catwalk horizontally with respect to the ground when: the jack portion moves the catwalk vertically with respect to the ground; and the leg is not in contact with the ground.

33. The apparatus of claim 26 wherein the catwalk further comprises a pipe pick-up mechanism connected with the frame, wherein the pick-up mechanism comprises an elevator operable to:

receive the pipe; and

lift the pipe from a lower position below the frame to an upper position adjacent an upper surface of the catwalk.

34. An apparatus comprising:

a catwalk comprising: a pipe delivery mechanism for moving a pipe to a drilling floor; a frame connected with the pipe delivery mechanism; a plurality of legs connected with the frame; and a pick-up mechanism adjacent the frame, wherein the pick-up mechanism is operable to: receive the pipe; and lift the pipe from a lower position below the pipe delivery mechanism to an upper position adjacent an upper surface of the catwalk.

35. The apparatus of claim 34 wherein the pick-up mechanism comprises:

a structural member extending between the lower position and the upper position; and

an elevator operable to: receive the pipe; and move along the structural member to lift the pipe from the lower position to the upper position.

36. The apparatus of claim 35 wherein the structural member is movable between:

a vertical position in which the structural member extends substantially vertically between the lower position and the upper position; and

a horizontal position in which the structural member extends substantially horizontally.

37. The apparatus of claim 35 wherein the pick-up mechanism is connected with the frame, and wherein the elevator is located below the frame when in the lower position.

38. The apparatus of claim 34 wherein each leg is configured to:

change vertical length of the leg to change height of the frame above the ground; and

move horizontally with respect to the frame to change distance between the legs on opposing sides of the frame.

39. The apparatus of claim 38 wherein each leg is configured to change vertical length and move horizontally with respect to the frame to accommodate beneath the frame a wellbore cellar and/or a Christmas tree connected over a wellbore.

40. The apparatus of claim 38 wherein each leg comprises:

a vertical inner portion that telescopes within a vertical outer portion to change the vertical length of the leg; and

a horizontal inner portion that telescopes within a horizontal outer portion to move the leg horizontally with respect to the frame.