Tool driving or impacting – Processes
Reexamination Certificate
2000-04-06
2003-10-21
Smith, Scott A. (Department: 3724)
Tool driving or impacting
Processes
C173S028000, C173S184000, C173S186000
Reexamination Certificate
active
06634436
ABSTRACT:
FIELD OF THE INVENTION
The present invention is in the field of oil exploration and drilling. In particular, the present invention is a mobile land rig and method for the rapid placement, assembly, disassembly, and repositioning of an oil drilling rig and associated drilling equipment.
BACKGROUND OF THE INVENTION
Conventional oil drilling and exploration in major land drilling operations require the rapid deployment, assembly and disassembly of drilling structures. Consequently, the transportability of components and the speed at which components can be assembled with the minimum amount of auxiliary equipment are paramount concerns. A transportable oil drilling rig typically includes, for example, a support base, a mast, pipe sections, and a drill floor. Often times however, auxiliary support equipment such as cranes are required to facilitate the setup and takedown of large components such as the base, the drill floor, the pipe racking board, and the like having the effect of increasing operational costs.
Drilling sites are often located in remote areas requiring truck transportation of the components of the rig accompanied by equipment used to assemble the rig. Further complicating the rig assembly process is the persistent need to change locations once a hole is sunk and it is determined whether the site will be sufficiently productive to merit a pumping installation, whether the site will be unproductive all together, or whether a more ideal location exists to sink a hole. Typically, site changes can occur once every several months, and, in response, prior art systems have attempted to increase the degree of mobility of rig components. Auxiliary equipment however is still necessary for performing steps such as placing the drill floor.
Since the variable costs associated with leased support equipment, such as cranes and the like, are calculated on a per hour or per day basis, expediting the takedown, transport, and setup operations is crucial for minimizing equipment leasing costs. Typical takedown and setup time is in the order of days. With equipment leasing costs ranging from several hundred dollars per day or more, many thousands of dollars in costs may be incurred for each end of a setup and takedown operation. For larger or more complex rigs, the cost may be even higher. In general, prior art drilling rigs are geared towards facilitating rapid setup, takedown and transport but still require external cranes, external winches, and the like which are most often leased increasing overall expense.
One such prior art system for erecting an oil well derrick is shown in U.S. Pat. No. 3,922,825 issued to Eddy's et al on Dec. 2, 1975. Eddy's system employs a stationary substructure base and a movable substructure base mounted thereon. Eddy's movable substructure base is coupled to the stationary base but swings upright into an elevated position on a series of struts that are connected to the stationary base with swivel connections at each end. Eddy's movable base is otherwise stationary given that neither the stationary base nor the “movable” base are mobile or repositionable without the use of an auxiliary crane or the like. Moreover, simply raising the movable substructure base and the drill mast requires the use of a winch mounted on an auxiliary winch truck.
Another prior art system for assembly of a drill rig is shown in U.S. Pat. No. 3,942,593 issued to Reeve, Jr., et al on Mar. 9, 1976. The mobile well drilling rig apparatus shown in Reeve comprises a trailerable telescoping mast and a separate sectionable substructure assembly further comprising a rig base, a working floor, and a rail means. The mast is conveyed to the top of the substructure by rollers and may be raised by hydraulic raising means to the upright position. Some of the disadvantages of such a system are the sheer length of the mast assembly when transporting and the instability of the mast while raising. A further disadvantage of the system of Reeve is the need for drawlines and winch means to raise the mast onto the working floor.
In addition to the need for auxiliary equipment such as winch trucks and the like, each of the above mentioned systems requires some stationary substructure that must be set down prior to the imposition of any additional structure thereupon. Further movement or repositioning of the base structure requires cranes or other heavy equipment to effect movement even in the case of the purported “movable” base structure of Eddy.
OBJECTS OF THE INVENTION
It would be desirable therefore for a mobile land rig that was self sufficient thus capable of being transported, erected, and disassembled without the need for auxiliary equipment. Such a system would save costs associated with leasing cranes and the like for periods of days during erection and disassembly of rigs.
It would further be desirable for a system with a self contained substructure base capable of being easily moved. Such a system would allow rapid placement and repositioning of the substructure base without the need for a crane or the like.
It would still further be desirable for a system having a substructure base that could be telescoped to a maximum operating height and automatically secured at such height yet possess structural rigidity sufficient to withstand winds and like forces incumbent on the mast structure. Further, the desirable system would be able to be collapsed to a minimum height to facilitate transport. Such a system would allow the substructure base to be easily transportable when collapsed yet sufficiently tall to support a drill mast when telescoped.
It would still further be desirable for a system capable of winching components into place with a self contained winching platform located on the drill mast. Such a system would allow rig components to be placed without the need for auxiliary equipment such as an external crane or winch.
It would be still further desirable for a system wherein all system components could be easily trailerable and transportable by truck. Such a system could be easily moved from one site to another with a minimum of setup and takedown time.
SUMMARY OF THE INVENTION
To meet the objects of the invention, a mobile land rig is provided for the transport assembly and disassembly of oil drilling equipment. The mobile land rig of the present invention comprises a mobile telescoping substructure box having wheel means integrated therein capable of supporting the mobile telescoping substructure box in rolling relation to the ground or drilling platform surface during transport. The mobile telescoping substructure box in the lowered position facilitates assembly of the mobile telescoping substructure box and the drill mast prior to and during mast erection. The mobile telescoping substructure box is typically raised into the fully extended position once the drill mast is fully erected as described hereinafter.
In the present invention, two such mobile telescoping substructure boxes are used to establish the base for the drill mast. The wheel means for allowing the mobile telescoping substructure box to roll may consist of one or more axle wheel assemblies preferably equipped with conventional heavy duty pneumatic rubber truck tires. The wheel means may further be provided with a selective raising and lowering means, such as a hydraulic lift, within the mobile telescoping substructure box to selectively engage and disengage the wheel assembly with a ground surface by lifting and lowering the substructure box in relation to the wheel means. When the mobile telescoping substructure box is correctly rolled into position, for example, the wheel assembly can be raised relative to the mobile telescoping substructure box and thereby establish direct contact between the ground and support footings or a support frame of the mobile telescoping substructure box. The support frame, in addition to bearing the load of the mobile telescoping substructure box and all structure attached thereto, may be equipped with load leveling means to ensure that the mobile telescoping substruct
Chukwurah Nathaniel
National Oilwell, L.P.
Smith Scott A.
Stevens Davis Miller & Mosher LLP
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