Abstract:
Improvements to base beams and self-propelled derrick rigs are described. The base beam can have two or more stabilizer arms which can be deployed. The base beam is also designed to support the derrick rig. An optional counterweight assembly can be connected to the front of the rig. The self-propelled derrick rig can be easily and quickly mounted to the base beam, and when mounted, the assembly will be able to withstand high hook loads and wind loading without the danger of the rig coming off of its wheels or falling over.

Description:
FIELD 
     This disclosure relates to apparatus and methods of stably supporting self-propelled derrick rigs such as workover rigs, drilling rigs, cranes and the like, using a portable base beam. 
     BACKGROUND 
     A completion or workover rig is used to do repair work on a well, such as tubing or pump replacement. When a workover rig is used to do repair work on a well, the rig must be able to pull weights near the rated capacity of the derrick of the rig, withstand high wind gusts, and otherwise be stably supported. Further, a workover rig should operate to its design capacity on a high frequency basis, and be highly mobile and self-contained. 
     A trend in workover rigs to maintain mobility and higher load capacities has been to use guy wires to stabilize the rig. The use of guys can significantly increase the rated capacity of the rig without changing the basic design. 
     However, there are drawbacks to a guy system. For example, guy wires need to be in specific locations for the stability and safe operation of the rig, and setup time is longer with a guy setup due to the specific locations. In addition, workover rigs typically tie off to permanent anchors set in the ground in a rectangular pattern around the well head. However, with the growing utilization of multi-well pads, it is nearly impossible to guy the workover rig to the anchors that were originally set in the ground when the well was drilled. 
     Solutions have been sought to solve the problem of a workover rig not being able to be supported by permanent anchors. One solution has been to utilize one or more base beams that are heavy, portable structures placed on the ground and to which the workover rig is guyed. Existing base beams have a relatively small footprint as well as set locations with which to attach guy wires, which makes set-up easier and faster. 
     SUMMARY 
     Improvements to base beams and self-propelled derrick rigs are described. A self-propelled derrick rig as used herein is intended to encompass any type of self-propelled vehicle that has a derrick structure mounted on it which can be moved to a raised position during use, a driver&#39;s cab and an engine for propelling the vehicle. Examples of self-propelled derrick rigs include, but are not limited to, workover rigs, drilling rigs, cranes and the like. 
     When the self-propelled derrick rig is mounted to the base beam, the assembly will be able to withstand high hook loads and wind loading without the danger of the rig coming off of its wheels or falling over. The self-propelled derrick rig can be easily and quickly mounted to the base beam. The assembly also allows support equipment, for example a portable pipe handling machine in the case of a workover rig, to work alongside it. In addition, the base beam can be transported as a single load on a vehicle, for example on a flatbed truck. 
     The base beam includes stabilizer arms that are attached, for example pivotally attached, to the base beam to help stabilize the base beam and the rig itself. A height adjustable stabilizer pad can be connected to each stabilizer arm to help level the stabilizer arms and the base beam on the ground. 
     In addition, to the base beam, a unique counterweight assembly is described that in use is connected to the front of the rig to help stabilize the rig and prevent the front of the rig from coming off of the ground. 
     In one embodiment, a base beam that is used to support a self-propelled derrick rig includes a longitudinally extending metal main beam having first and second opposite ends, a front side, a back side, a top and a bottom, where the bottom is substantially planar. The main beam includes a central section approximately midway between the first and second ends thereof on which the derrick structure of the rig will be supported. The central section can reinforced between the top and the bottom, and the top of the central section is substantially planar. First and second stabilizer arms are attached, for example pivotally attached or non-pivotally attached, to the main beam. when pivotally attached, the stabilizer arms are pivotable relative to the main beam between a refracted or transport position where the first and second stabilizer arms are generally parallel to the main beam and a fully extended or deployed position where the first and second stabilizer arms are not parallel to the main beam. In addition, at least one guy attachment point is provided on each of the first and second stabilizer arms to allow guys to attach between the derrick structure and the stabilizer arms. 
     In another embodiment, there can be a plurality of guy attachment points on the main beam. 
     In another embodiment, additional stabilizer arms can be provided on the main beam to provide even more stabilization. 
     In still another embodiment, an assembly is provided that includes a base beam and a self-propelled derrick rig. The base beam can include a longitudinally extending metal main beam having first and second opposite ends, a front side, a back side, a top and a bottom, and a central section. First and second stabilizer arms can be attached, for example pivotally attached or non-pivotally attached, to the main beam. When pivotally attached, the stabilizer arms are pivotable relative to the main beam between a retracted position where the first and second stabilizer arms are generally parallel to the main beam and a fully extended position where the first and second stabilizer arms are not parallel to the main beam. The self-propelled derrick rig can include a derrick structure adjacent a first end of the rig that is disposed in a raised position, a driver&#39;s cab, and an engine that provides power for propelling the rig. A base of the derrick structure can be supported on the central section of the main beam on the top thereof. In addition, a plurality of guys extend between the derrick structure and the rig, and a plurality of guys extend between the derrick structure and the base beam. 
     In yet another embodiment, the counterweight assembly includes a sled that has a mechanism to connect the sled to the self-propelled derrick rig. The connection can be the sled simply resting on the front of the rig to weigh down the front end, or the sled can be removably attached to the rig. A plurality of weights are removably disposed on the sled. Each weight is individually separable from the other weights and each weight is individually removable from the sled. 
     In another embodiment, a method of supporting a derrick structure of a self-propelled derrick rig is provided, where the derrick structure is disposed adjacent to a first end of the rig and is movable between a raised position and a lowered position. In the method, a base beam is arranged on the ground, and stabilizer arms that are pivotally or non-pivotally connected to the base beam are deployed from a retracted position to a fully deployed position. The self-propelled derrick rig is arranged adjacent to the base beam, and the derrick structure of the self-propelled derrick rig is raised to the raised position. A base end of the derrick structure is attached to the base beam. In addition, a plurality of guys are attached between the derrick structure and the remainder of the rig and a plurality of guys are attached between the derrick structure and the base beam. 
     In another embodiment of a method, a base beam is arranged on the ground, and the self-propelled derrick rig is arranged adjacent to the base beam. The derrick structure of the self-propelled derrick rig is raised to the raised position, and a base end of the derrick structure is attached to the base beam. A plurality of guys are attached between the derrick structure and the remainder of the rig and a plurality of guys are attached between the derrick structure and the base beam. A counterweight assembly is also connected to the rig at a second end thereof opposite the first end and the derrick structure to weigh down the front of the rig. 
    
    
     
       DRAWINGS 
         FIG. 1  illustrates an assembly including an exemplary self-propelled derrick rig mounted to an exemplary base beam. 
         FIG. 2  is a perspective view of the base beam in a folded condition. 
         FIG. 3  is a perspective view of the base beam with the stabilizer arms extended. 
         FIG. 4  is a perspective view of the derrick rig and the base beam at a point during assembly. 
         FIG. 5  is a close up view detailing an exemplary technique for fixing the derrick of the rig to the base beam. 
         FIG. 6  is a perspective view of the front of the derrick rig showing a counterweight assembly in place. 
         FIG. 7  is a detailed view of the counterweight assembly of  FIG. 6 . 
         FIG. 8  is a side view of the counterweight assembly of  FIG. 6 . 
         FIG. 9  illustrates the counterweight assembly disposed on top of the base beam during transport. 
         FIG. 10  illustrates an alternative embodiment of a base beam. 
         FIG. 11  illustrates another alternative embodiment of a base beam. 
         FIGS. 12A and 12B  illustrate still another alternative embodiment of a base beam in extended and folded conditions, respectively. 
         FIG. 13  illustrates another alternative embodiment of an assembly of a self-propelled derrick rig and a base beam. 
         FIG. 14  illustrates still another alternative embodiment of an assembly of a derrick rig and a base beam. 
         FIG. 15  illustrates still another alternative embodiment of an assembly of a derrick rig and a base beam. 
         FIG. 16  illustrates an exemplary attachment between the counterweight assembly and the rig. 
     
    
    
     DETAILED DESCRIPTION 
     As described in further detail below, an improved base beam is described that is used to support a self-propelled derrick rig. A self-propelled derrick rig as used herein is intended to encompass any type of self-propelled vehicle that has a derrick structure mounted on it which can be moved to a raised position during use, a driver&#39;s cab and an engine for propelling the vehicle. Examples of self-propelled derrick rigs include, but are not limited to, workover rigs, drilling rigs, cranes and the like. The self-propelled derrick rig will be described below as, and is illustrated in the drawings as, a workover rig. However, the derrick rig can be any other type of rig that can benefit from being supported using a base beam(s) as described herein. 
     With reference initially to  FIG. 1 , an assembly  10  is illustrated that includes a base beam  12  that is shown together with a self-propelled derrick rig  14  in the form of a workover rig. The base beam  12  is disposed adjacent to a well head  16 , with the rig  14  being used to perform a service function on the well. 
     The rig  14  includes a derrick structure  18  disposed adjacent to a first or rear end of the rig, where the derrick structure includes a raised position (shown in  FIG. 1 ) and a lowered position (shown in  FIG. 4 ). The rig  14  also includes a platform  20 , a driver&#39;s cab  22  disposed on the platform adjacent to a second or front end of the rig, wheels  24  mounted on the platform  20 , and an engine  26  adjacent to the front of the rig that provides power for propelling the rig during driving of the rig. 
     In the raised position of the derrick structure  18  shown in  FIG. 1 , a base of the derrick structure  18  is supported on the base beam  12 . In addition, a plurality of guys  28  extend between the derrick structure  18  and different points on the remainder of the rig  14 , and a plurality of guys  30  extend between the derrick structure  18  and the base beam  12 . 
     With reference to  FIGS. 2 and 3 , the base beam  12  includes a main beam  40  that extends along a longitudinal axis A-A from a first end  42   a  to a second, opposite end  42   b . The main beam  40  further includes a front side  44 , a back side  46 , a top  48  and a bottom (not visible in  FIGS. 2-3 ). The bottom is substantially planar to allow the main beam  40  to lay flat on the ground. In the illustrated example, the main beam  40  is generally rectangular in shape, although other shapes could be used. 
     The main beam  40  further includes a substantially planar central section  50  approximately midway between the first and second ends  42   a ,  42   b  thereof. As discussed further below with respect to  FIGS. 4-5 , in use the central section  50  supports the base of the derrick structure  18 . Therefore, if considered necessary to support the derrick structure, the central section  50  of the main beam can be reinforced between the top  48  and the bottom, for example by employing internal reinforcing members disposed within the main beam  40  at the central section  50 . 
     Further, first and second swing or stabilizer arms  52   a ,  52   b  are pivotally attached to the main beam  40 . In the embodiment illustrated in  FIGS. 2 and 3 , the swing arms  52   a ,  52   b  are pivotally attached to the main beam adjacent to the first and second ends  42   a ,  42   b , respectively. The swing arms are pivotable relative to the main beam  40  between a retracted position (shown in  FIG. 2 ) where the first and second swing arms are generally parallel to the main beam and a fully extended or deployed position (shown in  FIG. 3 ) where the first and second swing arms are not parallel to the main beam. 
     In an alternative embodiment, the stabilizer arms can be initially separate from the main beam  40  and then attached to the main beam in the extended or deployed position for use. In this embodiment, the stabilizer arms need not be pivotally attached since the arms are attached for use and detached (or not detached) during transport. 
     In the illustrated embodiment, when fully deployed, the swing arms  52   a ,  52   b  extend from the front side  44  of the main beam and are disposed at generally right angles to the longitudinal axis A-A. As shown in  FIG. 2 , each of the first and second swing arms has a length L, and the combined length of the first and second swing arms  52   a ,  52   b  can be less than the longitudinal length of the main beam to permit the swing arms to completely fold to the retracted position parallel to the axis A-A. However, as discussed further below, other configurations of the swing arms are possible. 
     Each swing arm  52   a ,  52   b  includes a first swing arm end  54  that is pivotally attached to the main beam, and a second swing arm end  56 . A stabilizer pad  58  is connected to the second swing arm end  56  of each swing arm. Each stabilizer pad  58  is adjustable in height to allow leveling of the swing arms and the base beam on uneven ground. 
     The base beam  12  is constructed primarily of a metal material such as steel. The main beam  40  between the top  48  and bottom is generally hollow. However, if additional weight for the base beam  12  is required, weights that are initially separate from the main beam can be disposed on the main beam adjacent to each of the ends  42   a ,  42   b . In one embodiment, concrete can be poured into the hollow interior of the main beam adjacent to the ends  42   a ,  42   b  to increase the weight of the base beam. In another embodiment, removable weights can be placed on top of the main beam adjacent to the ends thereof. However, any technique for adding weight to the base beam  12  to increase the weight of the beam can be used. 
     The base beam  12  further includes a plurality of guy attachment points to permit attachment to the guys  30 . The guy attachment points can be provided at locations that one determines to be suitable for adequately guying the derrick structure  18 . In the embodiment illustrated in  FIGS. 2 and 3 , there is at least one guy attachment point  60  on each of the first and second swing arms, for example adjacent to the second ends  56 . In addition, there can be a plurality of guy attachment points  62  on the main beam  40 , for example adjacent to the ends  42   a ,  42   b . The guy attachment points  60 ,  62  can be, for example, flanges that are attached to the base beam  12  and that include a hole to permit attachment of one end of the guys. The guys  30  (as well as the guys  28 ) can be wires or any structure suitable for use as guys. 
     Other configurations of the base beam are possible. For example,  FIG. 10  illustrates a base beam  212  with a main beam  240  and a pair of swing arms  252   a ,  252   b  pivotally attached to the main beam  240  for pivoting movement between a retracted position (not shown) where the first and second swing arms are generally parallel to the main beam and a fully extended or deployed position (shown in  FIG. 10 ) where the first and second swing arms are not parallel to the main beam. In this embodiment, the swing arms are pivotally attached to the main beam  240  so that the first and second arms  252   a ,  252   b  extend from a back side of the main beam when in the fully extended position in a direction generally toward the front end of the rig  14  and parallel to the rig. 
       FIG. 11  illustrates a base beam  312  with a main beam  340  and two pairs of swing arms  352   a ,  352   b ,  352   c ,  352   d  pivotally attached to the main beam  340  for pivoting movement between a retracted position (not shown) where the swing arms are generally parallel to the main beam and a fully extended or deployed position (shown in  FIG. 11 ) where the swing arms are not parallel to the main beam. In this embodiment, the swing arms are pivotally attached to the main beam  340  so that the swing arms  352   a ,  352   b  extend from a front side of the main beam similar to  FIGS. 2-3 , while the swings arms  352   c ,  352   d  extend from the back side of the main beam similar to  FIG. 10 . 
       FIGS. 12A and 12B  illustrate a base beam  412  with a main beam  440  and two pairs of swing arms  452   a ,  452   b ,  452   c ,  452   d  pivotally attached to the main beam  440  for pivoting movement between a retracted position (shown in  FIG. 12B ) where the swing arms are generally parallel to the main beam and a fully extended or deployed position (shown in  FIG. 12A ) where the swing arms are not parallel to the main beam. In this embodiment, the swing arms are pivotally attached to the main beam  440  so they extend from the front and back sides of the main beam similar to  FIG. 11 . In addition, each of the swing arms  452   a ,  452   b  includes a first section  454  that is pivotally attached to the main beam and a second section  456  that is pivotally attached to the first section. Constructing the arms  452   a ,  452   b  with two sections allows the two sections  454 ,  456  to fold together, for example one above the other as shown in  FIG. 12B , which allows the length of the arms to be increased, while allowing the arm sections  454 ,  456  to fold to the retracted position. 
       FIG. 14  illustrate a base beam  512  with a main beam  540  and a pair of swing arms  552   a ,  552   b  pivotally attached to the main beam  540  for pivoting movement between a retracted position (not shown) where the swing arms are generally parallel to the main beam and a fully extended or deployed position (shown in  FIG. 14 ) where the swing arms are not parallel to the main beam. In this embodiment, the swing arms  552   a ,  552   b  are pivotally attached to the main beam  540  away from the ends of the beam  540  and more toward the center of the main beam. In addition, the swing arms do not extend at right angles to the main beam as in the other embodiments. Instead, the swing arms  552   a ,  552   b  are disposed at acute angles a relative to the longitudinal axis of the main beam. 
     Returning now to  FIGS. 1-3  together with  FIGS. 4-5 , in use, the base beam is transported to a position adjacent to the well head  16  and arranged on the ground. The swing arms are then deployed from the retracted position, which is used during transport of the base beam, to the fully deployed position. If necessary, the stabilizer pads  58  are adjusted in height to level the swing arms and the main beam. The self-propelled derrick rig  14  is then backed up to a position adjacent to the base beam as shown in  FIG. 4 . During this time, the derrick structure  18  is likely at its lowered or transport position as shown in  FIG. 4 , although in some circumstances the derrick structure could already be raised or partially raised. If the derrick structure is not raised, the derrick structure is raised to the raised position shown in  FIG. 1 . 
     With reference to  FIG. 5 , once the derrick structure  18  is raised, a base end  70  of the derrick structure is attached to the base beam  12 . In particular, one side of the base end  70  is pivotally connected to the rig platform  20  by pivots  72 . The other side of the base end is provided with a pair of height adjustable stabilizer pads  74 . Metal plates  76  are laid on the top  48  of the main beam at the central section  50 , and the pads  74  rest on the plates  74 . The base end  70  is fixed to the main beam by one or more fixation members  78 . In one embodiment, four fixation members  78  can be used, each of which attaches at one end to the base end  70  of the derrick structure  18  and attach at opposite ends thereof to mounting fixtures  80  that are disposed adjacent to the front side and the back side respectively of the main beam adjacent to, and on opposite sides of, the central section  50 . In the illustrated embodiment, the fixation members  78  comprise shackles, although any type of fixation members that can adequately attach the base end of the derrick structure to the main beam can be used. 
     In addition, as shown in  FIG. 1 , the guys  28  are then attached between the derrick structure and the remainder of the rig, and the guys  30  are attached between the derrick structure and the base beam.  FIG. 1  illustrates the derrick structure  18  as including a rig floor  82  and a tubing or racking board  84  both of which are conventional structures on workover rigs. The guys  28  are illustrated as generally extending from the top of the derrick structure to other points on the rig. Some of the guys  30  extend from the base beam to the top of the derrick structure, while some of the guys  30  extend from the base beam to the tubing board  84  and from the tubing board to the top of the derrick structure. However, the exact arrangement and number of the guys  28 ,  30  can vary based on a number of factors, such as the expected loading conditions on the derrick structure and the rig. Therefore, the guy arrangement illustrated in  FIG. 1  is exemplary only and can vary from the illustrated arrangement both in the number of guys  28 ,  30  used and their locations. 
     Under some loading conditions, for example when the derrick structure is pulling at or near capacity, the front end of the rig  14  may want to come off the ground. To prevent such an occurrence, an optional counterweight assembly  90  can be used that is connected to the front end of the rig  14  to weigh down the front of the rig. The assembly  90  can simply connect to the front of the rig by resting on some portion of the front. Alternatively, the assembly  90  can be connected to the rig by removably attaching the assembly to the rig, for example by pinning or bolting the assembly to the rig. Any form of connection can be used as long as the assembly  90  increases the weight of the front of the rig. 
     With reference to  FIGS. 6-8 , the counterweight assembly  90  can include a sled  92  that is designed to connect to the rig  14  and carry separate weights  94  that can be added and removed from the sled  92  to alter the amount of weight carried by the sled. 
     The sled  92  is a generally rectangular structure that includes a base  96 , reinforcing members  98  at each side end of the base, a front side  100  and a rear side  102 . The rear side  102  of the sled  92  includes a plurality of vertical beams  104  connected at base ends thereof to the base  96  and at upper ends thereof to a horizontal beam  106 . As best seen in  FIG. 8 , the horizontal beam  106  and/or the beams  104  can be connected to a block, for example of wood, that rests on a ledge at the front of the rig. Thus, the assembly  90  weights down the front end of the rig. 
     If there is concern that the assembly could move, the assembly could be removably attached to the rig. For example, with reference to  FIG. 16 , the attachment mechanism can comprise flanges  116  that are fixed to the beam  106  and/or the beams  104 , with corresponding flanges  118  on the front of the rig that align with the flanges on the sled. Pins or bolts  119  can then extend through holes in the aligned flanges to attach the sled to the rig. 
     Each weight  94  is individually separable from the other weights  94  and each weight is individually removable from the sled  92 . The weights  94  are generally rectangular in shape and resemble plates. The sled can be designed to hold any number of weights, based in part on how much counterweight one may need. 
     To aid in mounting, removal and transport of the sled  92 , at least two forklift pockets  110  are formed in the base  96 . The forklift pockets  110  permit a forklift to lift and transport the sled  92 . Similarly, each of the weights  94  includes at least two forklift pockets  112  formed therein. The forklift pockets  112  permit a forklift to lift and transport each of the individual weights  94 . Instead of forklift pockets, any structure that performs a function similar to the forklift pockets can be used. 
     The sled  92  further includes at least one guy attachment point  114 . For example, in the illustrated embodiment, the sled includes a plurality of the guy attachment points  114 , with the guy attachment points being located at the rear side  102  of the sled. As best seen in  FIGS. 1 and 8 , two guys  28  extend from the derrick structure  18  to the attachment points  114  to guy the counterweight assembly to the derrick structure. 
     With reference to  FIG. 9 , the shape of the sled  92  is such that the sled  92  together with any weights held thereon can be disposed on the base beam  12  during transport of the base beam and the counterweight assembly. This minimizes the space taken up during transport. 
     With reference to  FIG. 13 , an embodiment is illustrated that uses two base beams. One base beam  120  is substantially similar to the base beam  12 . Alternatively, the base beam  120  could be similar to the base beams  212 ,  312 ,  412 , or  512 . A second base beam  122  is disposed underneath the rig  14 , for example underneath jacks or outriggers that are provided on the rig  14 . The construction and use of jacks or outriggers on rigs is well known in the art. In this embodiment, guys  124  extend from the derrick structure  18  and are connected to the ends of the second base beam  122  to help support the derrick structure. 
       FIG. 14  shows another embodiment that is similar to  FIG. 13 , but using the base beam  512  together with the second base beam  122 . 
       FIG. 15  shows another embodiment that uses two base beams, including one base beam  130  that is substantially similar to the base beam  12 . In this embodiment, a second base beam  132  is disposed underneath the rig  14  at a location that is further forward than the second base beam  122  in  FIG. 13 . For example, the second base beam  132  can be disposed underneath jacks disposed under the driver&#39;s cab  22 , and guys  134  extend from the derrick structure  18  and are connected to the ends of the base beam  132  to help support the derrick structure. 
     The second base beams  122 ,  132  illustrated in  FIGS. 13-15  are depicted as not including swing arms. However, the second base beams  122 ,  132  could be configured to have swing arms similar to those discussed above. 
     The individual features of the various embodiments described herein can be used individually or in any combination with any other embodiment described herein. 
     The examples disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.