Abstract:
A substructure of a drill rig includes, among other things, a base and an intermediate section that is adapted to be raised above the base, wherein the intermediate section is further adapted to be laterally moved in a first lateral direction relative to the base and maintained substantially parallel to the base during the raising of the intermediate section above the base. The substructure further includes a rig floor section that is adapted to be raised above the intermediate section, wherein the rig floor section is further adapted to be laterally moved in a second lateral direction relative to the base and maintained substantially parallel to the base during the raising of the rig floor section above the intermediate section, the second lateral direction being opposite to the first lateral direction.

Description:
This application claims priority from U.S. provisional patent application Ser. No. 61/262,232, filed on Nov. 18, 2009, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to road-transportable drill rigs for drilling boreholes into the earth to extract hydrocarbons, such as oil and natural gas, as well as other minerals. 
     2. Description of the Related Art 
     Drilling masts are the vertical structures used to support the drill string while a well is being drilled. Masts are usually rectangular in shape as opposed to the generally pyramidal shape of a derrick. The rectangular shape offers very good stiffness that allows the mast to be moved to a horizontal position for transport. Thus, drilling masts are very common on portable land rigs. 
       FIG. 1A  shows a mast assembly  120  for a transportable (i.e. portable) drill rig  100  of the prior art, but which has many components in common with the present invention. The mast assembly  120  has a derrick  112 , an A-frame  114 , as part of the rig structure  120 , on a rig floor  116  mounted to a substructure  118 . The mast  120  is pivotally connected to the floor  116 . The mast  120  is a typical drilling rig mast with top sheaves (not shown). The rig floor of this prior art drill rig is supported upon a base  122  with conventional cross-bracing members  118 ,  118   a , and  118   b  which brace the rig during operation. Typical components of these rigs  100  also include drawworks  130 , a control system  134  and other machinery well known and commonly used in the industry. 
     The rigs also typically have a number of structural members ( 140 A,  140 B &amp;  140 C) that carry the load of the rig  100  as it stands upright. However, since these rigs are portable, they are made to be collapsible during transport, and are therefore typically raised from a stacked/collapsed position with a wire rope system using the existing drawworks  130  system of the rig through a series of pulleys, or by hydraulic cylinders. Very high tension loads are applied to the wire rope during assembly, and a relatively complex series of pulleys, etc. may be required to raise the rig floor. It would be preferable to utilize a more easily controlled lifting system that did not require a cabling system carrying high tensile loads to raise these rig floors. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a sub-basement assembly for transportable, mobile drill rigs for supporting the drill rig floor. The assembly has a lower ‘stack’ height for transit but which can nonetheless be quickly and easily raised with a hydraulic cylinder as the substructure is erected. Although the height &amp; size of the present invention&#39;s ‘floor’ is quite compact while in shipment, it provides for the full load carrying capacity and full size of conventional ‘floors’ during drilling operations. The linkage structure provides the ability for the rig floor to be raised with a hydraulic cylinder with the linkage then locked in place as part of the fig floor support structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a side view of a prior art drill rig. 
         FIG. 1B  is a side view of a drill rig of the present invention, showing the support structure under the drill rig floor. 
         FIG. 2A  is a side view of the basement structure of the present invention when the floor is fully collapsed. 
         FIG. 2B  is a side view of the basement structure of the present invention when the floor is raised to about 15% of its height. 
         FIG. 2C  is a side view of the basement structure of the present invention when the floor is raised to about 50% of its height, showing the upper struts fully extended. 
         FIG. 2D  is a side view of the basement structure of the present invention when the floor is raised to about 75% of its height. 
         FIG. 2E  is a side view of the basement structure of the present invention when the floor is fully raised. 
         FIG. 3  is a side view of a basic arrangement of the linkage arrangement for the basement structure of the present invention 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1B , the drill rig  10  of the present invention includes a mast assembly  20  and many other components for a transportable (i.e. portable) drill rig  100  known in the prior art, and therefore has many components in common with the present invention. The mast assembly  20  of the present invention includes a mast  12 , an A-frame  14 , as part of the rig  10 , on a floor  16  mounted to a substructure  18 . The mast  12  is pivotally connected to the floor  16 . The mast  12  is a typical drilling rig mast with top sheaves (not shown). The rig floor  16  is supported upon the substructure  18  which is carried by the pivotable cross bracing links  46   a ,  46   b ,  46   c ,  46   d ,  46   e ,  46   f ,  46   g ,  46   h ,  46   i ,  46   j , and  46   k  of the present invention. Other components of the rig  10  may include drawworks  30 , a control system  34  and other machinery well known and commonly used in the industry. 
     The drill rig  10  is provided with a rig floor  16  elevating system which allows it to be raised from the shipping/stowed collapsed position as illustrated generally by  FIG. 2A  to the full operation position height as illustrated generally by  FIG. 2E . 
     While drill rigs of the prior art typically utilized flexible tension members, such as wire rope spooled on winches to provide the force required to raise the rig floor, the present invention uses a hydraulic cylinder  36  operating in compression to raise the rig floor in two or more stages. Generally, however, as will be seen, an even number of stages are preferred, although it is clear that having an odd numbers of stages is clearly within the scope of the present invention. 
     There is no particular order for raising the intermediate center section  40 ,  44  and the rig floor section  42 , so for convenience only, the raising process will be described with the rig floor section  42  being raised first, and the intermediate carrier section  40 , being raised second, from the rig base  38 . 
     In preparation for the first stage of the lifting operation, the hydraulic cylinder  36  is restrained at the base  38  and the rig floor section  42 . Although not necessarily a requirement, the linkages  46   f ,  46   g ,  46   h ,  46   i ,  46   j , and  46   k  may be locked in place to prevent the intermediate center section  40  from inadvertently lifting as the rig floor  16  portion is lifted. 
     The hydraulic cylinder  36  is then arranged to be connect between the base  38  and the rig floor  16 , to push the rig floor  16  upwards from the intermediate center section  40 . 
     As shown in more detail in  FIGS. 2A ,  2 B and  2 C, the pivotable links ( 46   a ,  46   c  and  46   e ) are pinned, or otherwise restrained between the rig floor  16  and the intermediate center section  40 . As the hydraulic cylinder  36  extends progressively as shown sequentially in  FIGS. 2A ,  2 B and  2 C, the pivotal rotation movement  34   a  of each of the links  46   a ,  46   c , and  46   e , and the horizontal movement of the rig floor  16  with respect to the base is evident. As is clear from the  FIG. 2C , when the floor section  16  is fully extended from the intermediate center section  40 , it is shifted a noticeable distance to the left, as viewed. As will be seen, however, this shifting at the intermediate stage will be compensated by a near equal rightward shift as the intermediate center section  40  is extended from the rig base  38 . Once the rig floor  16  is fully extended above the intermediate center section  40 , the links  46   b  and  46   d  are re-arranged in a manner such the rig floor section  42  is locked in an extended position with respect to the intermediate center section  40 . 
     Also notable in this view, is that the floor section  16  is moved leftward to its maximum distance from center. As previously stated, this lateral movement is compensated as intermediate center section  40  traverses in the opposite direction as the second stage of the lift progresses. 
     The second stage of the lifting process is an ‘opposing’ lift—i.e. the top structure moves sideways in the opposite direction (i.e. left to right as the figure is viewed) back to near centered as shown in  FIGS. 2D and 2E . In order to lift the intermediate center section  40  from the base  38 , it is first necessary to re-locate the hydraulic cylinder  36  to be pinned or restrained in some manner on one end to the base  38  and on the other end to the intermediate center section  40 , as shown generally by arrow  48  in  FIG. 2D . 
     Again the cylinder is extended until the intermediate center section  40  is fully extended from the base  38  as the links  46   g ,  46   i , and  46   k  are pivotally rotated as indicated at  34   b . In a manner similar to that described above, links  46   f ,  46   h  and  46   g  are then re-arranged, or new links added, to lock the intermediate center section  40  in place with respect to both the base  38  and the rig floor  42 —as shown in  FIG. 2   e.    
     Because the assemblies shift laterally during extension, an even number of opposing stages, as illustrated, are preferred. It would be appreciated by those skilled in the art, however, that odd numbers of stages may be used as well, especially if the extensions of some stages are significantly greater than others—or if the equipment arrangement on the rig floor causes more load on one side than the other. 
     The structure shown in  FIGS. 2A-2E  reflect one typical arrangement useful for raising relatively large drilling rigs  10 . However, the basic linkage required for the self-raising basement structure as disclosed herein, may be significantly simpler, as shown in  FIG. 3 . A minimal basement structure is shown in  FIG. 3 , which nonetheless performs in the same manner as the more elaborate structure illustrated in  FIGS. 2A-2E . 
     In  FIG. 3 , similar elements between the typical size drill rig  10  of the present invention as shown in  FIGS. 2A-2E  are illustrated in the ‘minimal’ rig arrangement  210  but with the identification numerals increased by 100. 
     The drill rig  210  of this ‘minimal’ embodiment is provided with a rig floor  216  elevating system which allows it to be raised from the shipping/stowed collapsed position similar to  FIG. 2A  to its full operation position height. 
     Again, there is no particular order for raising the intermediate center section  140  and the rig floor section  142  so again for convenience only, the raising process will be described with the rig floor section  142  being raised first, and the intermediate carrier section  140 ,  144 , being raised second, from the rig base  138 . Furthermore, for convenience the lifting process described below is described showing the rig floor  216  extended its full height, so all the elements may be clearly viewed. 
     In preparation for the first stage of the lifting operation, the hydraulic cylinder  136  is pinned or restrained in some manner at the base  138  and the rig floor  142 . The hydraulic cylinder  136  is then arranged to be connect between the base  138  and the rig floor  216 , to push the rig floor  216  upwards from the intermediate center section  140 , in a first operation, and then complete the raising of the rig floor  142  by raising the intermediate section in a second operation. 
     The pivotable links  146   b  and  146   c  are pinned between the rig floor  216 , the intermediate center section  140 , and the pivotable links  146   e  and  146   f  are pinned as shown. The process may then proceed in two steps, as described above, until both sections  140  are fully extended. As previously indicated, when the floor section  216  is fully extended from the intermediate center section  40  before it extends, it is shifted a noticeable distance to the left, as viewed. Again this shifting at the intermediate stage will be compensated by a near equal rightward shift the intermediate center section  140  is extended from the rig base  138 . Once the rig floor  216  is fully extended above the intermediate center section  140 , the links  146   a ,  146   b ,  146   c ,  146   d ,  146   e , and  146   f  are re-arranged in a manner such the rig floor  142  is locked in an extended position with respect to the intermediate center section  140 . 
     Those skilled in the art would appreciate that the height raised per lift section is related to the length of the individual links ( 46   a ,  46   b ,  46   c ,  46   d ,  46   e ,  46   f ,  46   g ,  46   h ,  46   i ,  46   j  and  46   k —and/or  146   a ,  146   b ,  146   c ,  146   d ,  146   e , and  146   f ) and their ‘stack height’. Therefore, this same type of structure could be expanded to include three, or four or more lift sections, as required. This would allow for much greater flexibility in rig design, and allow common sized linkage members over a wide range of different drill rig sizes and types. 
     Furthermore, drill rig floors of this new design are structurally lighter, they may be shorter in length, and be movable in fewer pieces than conventional portable drill rigs, enabling them to access drilling areas with hilly, winding roads, as are often encountered in mountainous areas. 
     Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.