Abstract:
A mobile drill rig includes a frame structure and a plurality of hinged outriggers that are adapted to be retractable to a substantially vertical position during a drilling operation and extendable to a substantially horizontal position during movement of the mobile drill rig. The frame structure is adapted to transfer a weight of the mobile drill rig through the plurality of hinged outriggers to a plurality of wheeled frame dollies during the rig movement.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a 371 of PCT/US10/44646, filed Aug. 6, 2010, which claimed priority from U.S. provisional patent application Ser. No. 61/232,075, filed Aug. 7, 2009. 
    
    
     FIELD OF THE INVENTION 
     The present invention is drawn to oilfield drilling structures which may be easily moved from one drilling position to another by use of outboard, hinged outriggers. These structures are useful in drilling oil wells in fields where a great many boreholes are required to sustain the production of oil. The invention further provides a drill rig having features which allow it to be transported along roadways from one oilfield drilling location to another. 
     DESCRIPTION OF THE RELATED ART 
     There are numerous patents and publication regarding ‘mobile’ oil well drilling rigs that may be transported in a ‘stowed’ mode along public highways and which may also be moved in an ‘erected’ mode when drilling multiple adjacent wells within a particular oil field. One such patent, U.S. Pat. No. 3,754,361, incorporated by reference herein for all it discloses, discussed a wheeled structure to transport a drilling rig with rotatable wheel assemblies which allow the rig to be moved by using a ‘fifth wheel’ arrangement which may be rotated to any angle. These wheels are permanently attached, however, which may consume considerable space and add unnecessary weight. 
     U.S. Pat. No. 4,375,892 discloses a more flexible ‘dolly type’ structure which also allows a rig to be moved in any desired direction. However, this structure shares many of the same general problems as U.S. Pat. No. 3,754,361, as described above. 
     Furthermore, U.S. Pat. Nos. 4,305,237; 4,290,495; 3,807,109; 4,823,953; 4,823,870 and US Publication number 2007/0215359 all show various arrangements for movable drill rigs. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure is generally directed to mobile drilling rig structures with hinged retractable outriggers. In one illustrative embodiment, a mobile drill rig includes, among other things, a frame structure and a plurality of hinged outriggers that are adapted to be retractable to a substantially vertical position during drilling operation and extendable to a substantially horizontal position during movement of the mobile drill rig. Furthermore, the frame structure is adapted to transfer a weight of the mobile drill rig through the plurality of hinged outriggers to a plurality of wheeled frame dollies during the rig movement. 
     In another exemplary embodiment, a hinged outrigger is disclosed that is operatively coupled to a mobile drill rig, and at least one servomechanism is operatively coupled to the hinged outrigger. The hinged outrigger is adapted to be retractable to a substantially vertical position during a drilling operation and extendable to a substantially horizontal position during movement of the mobile drill rig. Additionally, the hinged outrigger is further adapted to transfer weight of the mobile drill rig from a frame structure to one or more wheeled frame dollies during the rig movement. Furthermore, the at least one servomechanism includes at least one of a hydraulic servomechanism and a pneumatic servomechanism and is adapted to provide extension and retraction of the hinged outrigger and to facilitate electronic coordination of the rig movement. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view of a drill rig of the present invention. 
         FIG. 2  is a cut-away top view of wheeled frame dollies arranged to lie within the support columns of the drill rig of  FIG. 1 . 
         FIG. 3  is a side elevation view of the drill rig of  FIG. 1  arranged for transport along a public highway. 
         FIG. 4  is a top view of a cutaway portion of a structure similar to  FIG. 1 , to show wheeled frame dollies mounted outboard of the rig structure and carried on the hingable outriggers of the present invention. 
         FIG. 5  is an end elevation view of the structure and hinged outriggers of  FIG. 4 . 
         FIG. 6  is a top view of a cutaway portion of a structure similar to  FIG. 1 , to show wheeled frame dollies adapted to move the rig transversely, supported by the rig structure itself and with retracted hingable outriggers of the present invention. 
         FIG. 7A  is a top view of a cutaway portion of a structure similar to  FIG. 1 , showing wheeled frame dollies mounted inboard and supported by the rig structure itself and with retracted hingable outriggers of the present invention. 
         FIG. 7B  is an end elevation view of the structure and retracted hinged outriggers of  FIG. 7A . 
         FIG. 8A  is a side elevation view of a drill rig drilling a new borehole along a line of already drilled boreholes. 
         FIG. 8B  is a top view of a cutaway portion of a structure similar to  FIG. 8A . 
         FIG. 9  is an end elevation view of a portion of a drill rig with the retractable hinged outriggers of the present invention carrying the load of the drill rig and transferring it to the wheeled frame dollies. 
         FIG. 10  is an end elevation view of a portion of a drill rig showing the retractable hinged outriggers in the retracted position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to  FIG. 1 , the drill rig  12  of the present invention is a transportable type of drilling rig which allows it not only to be moved short distances such as the several hundred feet from one wellbore to be drilled to the next as illustrated in the configuration shown in  FIG. 1 , but which also may be disassembled, packaged and towed (as shown in  FIG. 3 ) over public highways from one location to another which may be hundreds of miles apart. 
     Since a fully assembled drill rig  12  may weigh several hundred tons, moving it for even very short distance may be challenging. The drill rig  12  of the present invention may be placed upon one or more wheeled frame dollies  18 , which are fitted with a number of wheels  14  (as shown in  FIG. 1 ) and may be pulled along by a single towing bar  16 . In some cases the wheeled dollies  18  with rotatable wheels  14  are towed to the next well site by each of their individual tow bars  22 , as shown in  FIG. 2 . 
     Alternately, (and preferably) these dollies  18  may have motors built into their wheels  14  which allow them to be self propelled. In this case, each of the wheels  14  of the wheeled dollies  18  may be independently powered and individually and independently turned to the left or right to steer the drill rig  12  as it is being moved. In addition, the dollies  18  may have built-in jacking devices which allow them to be placed under the substructures  24  and elevated to contact and lift the drill rig  12 . The drill rig  12  of the present invention as shown in  FIGS. 1-10  is adapted to be carried upon these wheeled frame dollies  18 . 
     In both ways of moving the rig  12  described above, there is a further option of placing the wheeled dollies  18  either under the drill rig  12  as shown in  FIGS. 7A and 7B , or by placing the wheeled dollies  18  on either side of the outside portion of the drill  12  rig, as shown for example in  FIGS. 4-6 . In this case a pair of hinged outriggers  26  may be lowered and locked in place to transfer the weight of the rig to the wheeled frame dollies  18 . 
     As oil fields become more depleted, it often requires many more boreholes to produce commercially amounts of oil. Also, some types of formations do not have good fluid communications. In both of these cases, it is often desirable to drill numerous boreholes in a grid pattern.  FIG. 8B  illustrates one such configuration for a line of boreholes  28 A,  28 B,  28 C and  28 D. 
     When this needs to be done, the task of moving the drill rig  12  becomes even more challenging, as it is now required to move both fore and aft, as well as left and right, as it moves from one line to the next. In the prior art drill rigs, the rig had to be rotated 90 degrees to make this turn, as the wellbore of the previously drilled wells may restrict the movement of the rigs—as shown for example in  FIGS. 8A and 8B , which are side, and plan views of the drill rig  12  of the present invention drilling another in a series of boreholes  28 A,  28 B,  28 C,  28 D. 
     Again, because the drill rig  12  of the present invention has the capability of moving both laterally with the wheeled frame dollies  18 , and longitudinally by utilizing the hinged outriggers  26  with the wheeled frame dollies  18 , this formerly daunting task of a combination of lateral and longitudinal movement may be accomplished in far less time with far less risk of damaging the drill rig  12  or the other equipment at the site, as compared with present practice. Furthermore, the hinged outriggers  26  of the present invention may include the use of conventional hydraulic, pneumatic, servo type mechanisms, which could provide for automatic extension/retraction, and allow for electronic coordination of movement. This may be combined with other systems, and allow electronic synchronization with other rig equipment for very complex moving tasks, where multiple devices may be optionally controlled with computerized control systems. 
     A further advantage of the hinged outriggers is that when the rig  12  is partially dismantled for transport (as shown in  FIG. 3 ) the load may be narrower because when stowed, the outriggers may no longer protrude beyond the frame structure of the rig. 
     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.