The present invention relates to the mobile rig including the carrier frame, a mast, a top drive, and a coil tubing injector. More particularly, the mobile drilling rig includes a first dolly and a second dolly, each for selective engagement with the carrier frame during transport.
Various techniques have been devised in an attempt to maximize the benefit of a trailer. Trailers are, of course, widely used to transport goods, and in particular heavy equipment. U.S. Pat. No. 6,371,505 discloses a double gooseneck trailer for hauling large, heavy loads. U.S. Pa. No. 6,767,172 discloses a low loader trailer, and in particular a front loading flatbed trailer.
Unique problems are presented when transporting a drilling rig, and in particular a drilling rig of a type which includes a coil tubing injector for injecting coil tubing into the well, and a top drive unit for handling conventional threaded tubulars during other well operations. U.S. Publication 2005/0194189 discloses a mobile drilling rig which is fabricated in three sections for transport to and installation at a drilling site. Publication 2004/0240973 discloses a transportable oil rig which includes in one embodiment a mast dolly positioned near the rear of the trailer. The mast dolly includes a set of wheels and an adjustable height support framework to stabilize the dolly and keep it level. The assembly may be made up and disassembled at the well site. Publication 2005/0193645 discloses another mobile drilling rig comprising two substructure sections and a mast section which may be assembled at the well site. Publication 2004/0211598 discloses a drilling rig with a specialized positioning dolly and an adjustable fifth-wheel truck connection for transporting the mast to the drill site for assembly.
The disadvantages of the prior art are overcome by the present invention, an improved mobile drilling rig is hereinafter disclosed.
In one embodiment, a mobile drill comprises a carrier frame and a mast supported on the frame during transport. The mast is raised to an operative position over a well. A top drive is supported on the mast when in operative position and it is moveable along an axis of the mast. A coil tubing injector is supported on the mast when in the operative position for injecting coil tubing into the well. A first dolly assembly for supporting the carrier frame is provided, with the first dolly assembly comprising a first plurality of wheels on a first plurality of axles. The first dolly assembly is adapted for selectively attachment to and detachment from the carrier frame, and supports the carrier frame during transport. A second dolly assembly is provided for replacing the first dolly assembly. In many applications, the second dolly assembly will have a different plurality of wheels and/or a different plurality of axles than the first dolly assembly.
According to one embodiment, a method of transporting and operating a drilling rig comprises providing at least one carrier frame, and supporting a mast on the at least one carrier frame for raising to an operative position over a well. A top drive is supported on the mast when in operative position and is moveable along an axis of the mast. A coil tubing injector is supported on the mast when in operative position for injecting coil tubing into the well. A first dolly assembly including a first plurality of wheels and a first plurality of axles is provided for selective attachment to and detachment from the carrier frame, and a second dolly assembly with a second plurality of wheels and a second plurality of axles is also provided for selective attachment to and detachment from the carrier frame. According to the method, one of the first and second dolly assemblies is removed from engagement with the carrier frame and the other of the first and second dolly assemblies is connected with the carrier frame.
These further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.
In one embodiment, the top drive 16 and the coiled tubing injector 20 are each supported on the carrier frame 14 during transport. As shown in
Referring to
As shown in
The embodiments discussed above include a carrier frame for supporting the mast, the top drive, and the coil tubing injector. The coil tubing reel, or optionally the coil tubing reel and the injector, may be provided on a second carrier frame structurally separate from the carrier frame which carries the mast and the top drive during transport.
Referring now to
It should be understood that the dolly assembly 84 as shown in
For the illustrated embodiments, the dolly may be detached and slid rearward away from the frame or carrier. In other applications, the positioning of the outriggers may facilitate removal of one dolly and replacement with another dolly from the left side or the right side of the carrier.
For each of the embodiments disclosed herein, the carrier frame, or each of the carrier frames, if a separate carrier frame is provided for the coil tubing reel, operates to carry a substantially fixed load, i.e., the load comprises the equipment supported on and secured to the carrier frame. This is to be distinguished from a flat bed trailer which may be sized to receive a variable load skid mounted carrier frame supported on the flat bed trailer for transportation to another site. Such a flat bed trailer does not support a fixed load, since the load is not permanently secured to the flat bed trailer, and instead is placed on the flat bed trailer, latched to the trailer with chains or cables, transported to the site, and then detached from the flat bed trailer. A significant advantage of the embodiments disclosed herein compared to rigs which use a flat bed trailer relates to the substantial cost and difficulty associated with unloading and loading a rig from a flat bed trailer, and the desired ability of the carrier frame according to the present invention to be placed very low relative to the ground surface during transport, the ability to quickly set up the rig components for a drilling operation, a low center of gravity for the rig carrier frame when drilling, and the ability to quickly and easily move the rig to another location when the drilling operation is complete.
As disclosed herein, the first dolly differs from the second dolly in that at least one of the dollies has a different number of axles or a different position of the axles, or a different number of wheels on one or more of the axles, compared to the other dolly assembly. Thus one dolly assembly is better able to satisfy strict load regulations, while the other dolly assembly may be used in locations where the regulations are not as strict. In either case, the versatility of the rig is significantly improved because of the interchangeability of the dollies. The first dolly assembly may thus have a plurality of wheels which is the same or different than the second dolly assembly, and the first dolly assembly has a number or location of axles which are different than the second dolly assembly. In most cases, one dolly assembly will have a different number of wheels than the other dolly assembly, and will have a different number of axles than the other dolly assembly.
Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations, and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.