Patent Publication Number: US-9404318-B2

Title: Top drive counter moment system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from and the benefit of U.S. Provisional Application Ser. No. 61/666,529, entitled “Top Drive Counter Moment System,” filed Jun. 29, 2012, which is hereby incorporated by reference in its entirety. 
     BACKGROUND 
     Embodiments of the present disclosure relate generally to the field of drilling and processing of wells. More particularly, present embodiments relate to a system and method for stabilizing a top drive during a drilling process, a casing process, or another type of well processing operation. 
     Top drives are typically utilized in well drilling and maintenance operations, such as operations related to oil and gas exploration. In conventional oil and gas operations, a well is typically drilled to a desired depth with a drill string, which includes drill pipe and a drilling bottom hole assembly (BHA). During a drilling process, the drill string may be supported and hoisted about a drilling rig by a hoisting system for eventual positioning down hole in a well. As the drill string is lowered into the well, a top drive system may rotate the drill string to facilitate drilling. 
     BRIEF DESCRIPTION 
     In accordance with one aspect of the disclosure, a top drive system includes a hoisting assembly; an upper link of the housing assembly, a lower link of the housing assembly, and a first joint coupling the upper link and the lower link. The top drive system also includes a main body coupled to the hoisting assembly by a second joint, wherein the hoisting assembly is configured to support the main body, and the main body is configured to support a tubular. Further, the top drive system includes a frame coupled to the main body and a counter moment system configured to apply a force on the first joint to create a bending moment about the second joint. 
     Another embodiment includes a top drive system including a hoisting assembly, a main body coupled to the hoisting assembly by a first joint, wherein the hoisting assembly is configured to support the main body, and the main body is configured to support a tubular, a frame coupled to the main body, a torque track system comprising a torque bushing, and a counter moment system configured to apply a force on a second joint of the hoisting assembly to create a bending moment about the second joint. 
     In accordance with another aspect of the disclosure, a method includes coupling a main body of a top drive system to a hoisting assembly with a first joint, suspending the main body of the top drive system with the hoisting assembly, and applying a force to a second joint of the hoisting assembly to create a bending moment about the first joint. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of present embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a schematic of a well being drilled, in accordance with present techniques; 
         FIG. 2  is a side view of a top drive having a counter moment system, in accordance with present techniques; and 
         FIG. 3  is a side view of a top drive having a counter moment system, in accordance with present techniques. 
     
    
    
     DETAILED DESCRIPTION 
     It is now recognized that top drive systems may have a center of gravity that is offset from a hanging load of the top drive system. Specifically, it is now recognized that the offset center of gravity may cause an overturning moment acting on the top drive system, which may result in excessive or premature wear on top drive system components or other components coupled to the top drive system. Accordingly, there is a presently recognized need to reduce or counterbalance overturning moments acting on a top drive system and related components. 
     Present embodiments provide a counter moment system for a top drive system. Specifically, the counter moment system is configured to create a force acting on a link or joint of a hoisting system. As the counter moment system creates the force acting on the link or joint of the hoisting system, a reaction force acting on the link or joint produces a counter moment on the top drive system. In certain embodiments, the counter moment counterbalances a overturning moment acting on the top drive caused by an offset center of gravity of the top drive system. In this manner, forces caused by the overturning moment and acting on other components of the top drive system, such as a torque bushing of a torque track system, may be reduced, thereby reducing premature and excessive wear on the torque bushing. Thus, present embodiments improve top drive performance and prolong the useful life of a top drive. 
     Turning now to the drawings,  FIG. 1  is a schematic of a drilling rig  10  in the process of drilling a well in accordance with present techniques. The drilling rig  10  features an elevated rig floor  12  and a derrick  14  extending above the rig floor  12 . A supply reel  16  supplies drilling line  18  to a crown block  20  and traveling block  22  configured to hoist various types of drilling equipment above the rig floor  12 . The drilling line  18  is secured to a deadline tiedown anchor  24 , and a drawworks  26  regulates the amount of drilling line  18  in use and, consequently, the height of the traveling block  22  at a given moment. Below the rig floor  12 , a drill string  28  extends downward into a wellbore  30  and is held stationary with respect to the rig floor  12  by a rotary table  32  and slips  34 . A portion of the drill string  28  extends above the rig floor  12 , forming a stump  36  to which another length of tubular  38  may be added. A top drive  40 , hoisted by the traveling block  22 , positions the tubular  38  above the wellbore before coupling with the tubular  38 . The top drive  40 , once coupled with the tubular  38 , may then lower the coupled tubular  38  toward the stump  36  and rotate the tubular  38  such that it connects with the stump  36  and becomes part of the drill string  28 . Specifically, the top drive  40  includes a quill  42  used to turn the tubular  38  or other drilling equipment. 
       FIG. 1  further illustrates the top drive  40  with a counter moment system  44 . As discussed below, the center of gravity of the top drive  40  may not be centered above the quill  42  and/or tubular  38  (e.g., a hanging load of the top drive  40 ). Consequently, the top drive  40  may experience a moment or rotating force (e.g., an overturning moment), which is counterbalanced by other features. For example, a torque track or dolly system of the top drive  40  may function to counterbalance the moment. In other words, the torque track or dolly system (e.g., a torque bushing of the torque track) may experience forces that counteract the overturning moment created be the unbalanced center of gravity of the top drive  40 . As a result, components of the torque track or dolly system (e.g., a torque bushing) may experience excessive and/or premature wear. As discussed in detail below, the counter moment system  44  of the top drive  40  is configured to produce a counter moment that counteracts the overturning moment created by the unbalanced center of gravity of the top drive  40 . For example, a force may be applied to one or more components of the top drive  40  that creates a reverse bending moment (e.g., a counter moment) that partially or completely counter balances the overturning moment acting on the top drive  40 . In this manner, the forces acting on certain features (e.g., the torque track or dolly system) due to the overturning moment may be reduced, thereby reducing excessive and premature wear on one or more of the features. 
     It should be noted that the illustration of  FIG. 1  is intentionally simplified to focus on the top drive  40  with the counter moment system  44  described in detail below. Many other components and tools may be employed during the various periods of formation and preparation of the well. Similarly, as will be appreciated by those skilled in the art, the orientation and environment of the well may vary widely depending upon the location and situation of the formations of interest. For example, rather than a generally vertical bore, the well, in practice, may include one or more deviations, including angled and horizontal runs. Similarly, while shown as a surface (land-based) operation, the well may be formed in water of various depths, in which case the topside equipment may include an anchored or floating platform. 
       FIG. 2  is a side view of an embodiment of the top drive  40  having the counter moment system  44 . In the illustrated embodiment, the top drive  40  includes a hoisting assembly  50 , which includes an upper link  52  and a lower link  54 , which are coupled to one another by a joint  56  (e.g., a pin joint). The lower link  54  is also coupled to a main body  58  of the top drive  40  with a joint  60  (e.g., a pin joint). The main body  58  of the top drive  40  is further coupled to other components of the top drive  40 . For example, the main body  58  is coupled to a frame  62  of the top drive  40  and the quill  42  of the top drive  40 . The main body  58  further includes a torque and drive system  64 , which operates to drive rotation of the tubular  38  supported by the top drive  40  by applying a torque to the quill  42 . In the illustrated embodiment, the tubular  38  is coupled to the quill  42  by link arms  66  and an elevator assembly  68 . 
     As mentioned above, the top drive  40  has a center of gravity  70  that is not centered above the quill  42  and/or the tubular  38  supported by the top drive  40 . That is, the center of gravity  70  (e.g., gravitational force  72  of the top drive  40 ) is offset a distance  74  from an axis  76  of the hanging load (i.e., the quill  42  and/or the tubular  38 ) of the top drive  40 . As a result, the top drive  40  experiences an overturning moment  78  about the joint  60 . As will be appreciated, the overturning moment  78  is equal to the gravitational force  72  times the distance  74  that the center of gravity  70  is offset from the axis  76  of the hanging load. It should be noted that the size of the arrow representing the overturning moment  78  does not reflect the magnitude of the overturning moment  78 . 
     In the illustrated embodiment, the top drive  40  includes a torque track system  80  having a torque bushing  82 . As mentioned above, the overturning moment  78  acting on the top drive  40  may be counterbalanced or counteracted by the torque bushing  82  of the torque track system  80 , which may cause excessive or premature wear and/or degradation in the torque bushing  82  and or other components of the torque track system  80 . For example, the overturning moment  78  acting on the top drive  40  may cause a reactive moment  84  to act on the torque bushing  82 . More specifically, as the overturning moment  78  acts on the top drive  40 , the torque track system  80  may experience resultant forces  86  and  88 , which are separated by a length  90  of the torque track system  80  and which create the reactive moment  84  acting on the torque bushing  82 . To reduce the forces (e.g., the reactive moment  84 ) acting on the torque bushing  82  resulting from the overturning moment  78 , the top drive  40  includes the counter moment system  44 , which operates in the manner described below. 
     By way of example, in one embodiment, the gravitational force  72  of the top drive  40  may be approximately 40,000 pounds, and the distance  74  that the center of gravity  70  is offset from the axis  76  of the hanging load of the top drive  40  may be approximately 0.5 feet. As a result, the overturning moment  78  acting on the top drive  40  may be approximately 20,000 foot-pounds of torque. As mentioned above, the torque bushing  82  counterbalances or counteracts the overturning moment  78 . That is, the reactive moment  84  acting on the torque bushing  82 , which may be approximately equal to the overturning moment  78 , counterbalances or counteracts the overturning moment  78 . Therefore, in the present example, the reactive moment  84  may be approximately 20,000 foot-pounds acting on the torque bushing  82 . Moreover, when the reactive moment  84  is approximately 20,000 foot-pounds, the reactive forces  86  and  88  may be equal to approximately 3,333 pounds of force when the length  90  of the torque track system  80  is approximately 6 feet. 
       FIG. 3  is a side view of an embodiment of the top drive  40  having the counter moment system  44 , illustrating the counter moment system  44  in operation. The illustrated embodiment includes similar elements and element numbers as the embodiment shown in  FIG. 2 . 
     As mentioned above, the counter moment system  44  is configured to apply a force on components of the top drive  40  to produce a counter moment that reverses or counterbalances the overturning moment  78  created due to the offset center of gravity  70 , thereby reducing the forces acting on the torque bushing  82 . More specifically, the counter moment system  44  is configured to apply a force, represented by arrow  100 , on the joint  56  coupling the upper link  52  and the lower link  54  of the hoisting assembly  50 . The force  100  may be applied to the joint  56  in a variety of manners. In the illustrated embodiment, the counter moment system  44  includes a bracket  102  that is coupled to the frame  62  of the top drive  40 . For example, the bracket  102  may be fixedly attached to the frame  62 . In other words, the bracket  102  may not rotate or pivot relative to the frame  62 . Additionally, the bracket  102  is coupled to and supports a hydraulic cylinder  104  and a pulley  106 . As shown, a cable  108  is coupled to the hydraulic cylinder  104 , extends along the bracket  102 , is routed around the pulley  106 , and is coupled to a pin  110  of the joint  56 . 
     In operation, the hydraulic cylinder  104  compresses, thereby pulling or drawing the cable  108  in a direction  112 . In certain embodiments, the compression and/or operation of the hydraulic cylinder  104  may be controlled by a controlled pressure circuit. Additionally, the hydraulic cylinder  104  may be configured to compress and thereby pull the cable  108  with a constant force. Furthermore, the amount of constant force with which the hydraulic cylinder  104  compresses may vary depending on various factors. For example, the force of the hydraulic cylinder  104  compression may vary depending on the length of the bracket  102 , the weight of the top drive  40 , the amount of hanging load supported by the top drive  40 , and so forth. As the hydraulic cylinder  104  is compressed and the cable  108  is pulled, the force of the cable  108 , which is redirected by the pulley  106 , pulls the pin  110  and the joint  56  such that they are translated in a direction  114 . In other words, the force  100  acting on the pin  110  and the joint  56  is created by the cable  108  that is being pulled by the hydraulic cylinder  104  as its compresses. As the pin  110  and the joint  56  are pulled in the direction  114 , the lower link  54  is rotated over the center of gravity  70  of the top drive  40 . 
     Additionally, a reaction force  115  acts on the pin  110  and the joint  56  as the counter moment system  44  applies the force  100  to the pin  110  and joint  56 . As will be appreciated by those skilled in the art, the reaction force  115  acting on the pin  110  and the joint  56  produces a counter moment  116  acting on the top drive  40 . More specifically, the counter moment  116  is equal to the reaction force  115  times a distance  118  from the pin  110  of the joint  56  to a pin  120  of the joint  60 . As shown, the counter moment  116  counterbalances or counteracts the overturning moment  78 . As similarly noted above, the size of the arrow representing the counter moment  116 , as well as the relative sizes of the arrows representing the overturning moment  78  and the counter moment  116  are not representative of the respective magnitudes of the moments  78  and  116 . In certain embodiments, the operation of the hydraulic cylinder  104  may be regulated such that the magnitude of the force  100  (and therefore a resultant force  114 ) results in the counter moment  116  being equal and opposite to the overturning moment  78  acting on the top drive  40 . In this manner, the forces acting on the torque bushing  82  caused by the overturning moment  78  (e.g., the reactive moment  84 ) may be reduced, thereby reducing premature or excessive wear and degradation on the torque bushing  82 . 
     In other embodiments of the counter moment system  44 , other methods or components may be used to produce the force  100  acting on the pin  110  and the joint  56 . For example, instead of the hydraulic cylinder  104 , the counter moment system  44  may include a spring mechanism (e.g., a preloaded spring mechanism), magnetic mechanism, electrical mechanism, and so forth. Alternatively, the counter moment system  44  may include a counter weight (e.g., a hanging mass and pulley system) to have a gravity-based counter moment system  44 . In other embodiments, the counter moment system  44  may include any other device or mechanism capable of applying a linear force (e.g., in the direction  114 ) on the pin  110  and the joint  56 . 
     By way of example, in one embodiment, the gravitational force  72  of the top drive  40  may be approximately 40,000 pounds, and the distance  74  that the center of gravity  70  is offset from the axis  76  of the hanging load of the top drive  40  may be approximately 0.5 feet. As such, the overturning moment  78  is approximately 20,000 foot-pounds of torque. As discussed in detail above, to provide the counter moment  116 , the force  100  is applied to the joint  56 . Specifically, the force  100  may be equal to the amount of the overturning moment  78  divided by the distance  118  from the pin  110  of the joint  56  to the pin  120  of the joint  60 . In the present example, if the distance  118  is approximately 7 feet, then the force  100  applied to the pin  110  may be equal to approximately 2,857 pounds. As a result, the lower link  54  may be biased at an angle  122  relative to the axis  76  of the hanging load (i.e., the quill  42  and/or the tubular  38 ) of the top drive  40 . In the present example, the angle  122  may be approximately equal to the arctangent of (2,587/40,000), or approximately 4.08 degrees. As a result, a force  124  acting on the lower link  54  may be approximately equal to (1/cosine(4.08)*40,000), or 40101 pounds. Furthermore, in the present example, a distance  126  that the pin  110  is offset from the axis  76  when the force  100  is applied may be approximately equal to sin(4.08)*7 feet, or approximately 0.5 feet. 
     Continuing with the present example, if the top drive  40  were loaded with 40,000 pounds of tubular  38 , then a total force  128  acting on the top drive  40  would equal approximately 40,000 pounds of tubular  38  plus the 40,000 pound weight of the top drive  40  (e.g., gravitational force  72 ), or 80,000 pounds. Using similar calculations discussed above, if the force  100  applied to the pin  110  to counter act the overturning moment  78  remained at 2,857 pounds, then the center of gravity  72  of the top drive  40  would shift toward the axis  76  by 0.25 feet (i.e., arc tangent of (2,857/80,000), or approximately 0.25 feet). 
     As discussed in detail above, embodiments of the present disclosure are directed towards a counter moment system  44  for the top drive  40 . Specifically, the counter moment system  44  is configured to produce a force (e.g., the force  100 ) acting on the pin  110  and the joint  56  coupling the upper and lower links  50  and  52 . As the counter moment system  44  creates the force  100  acting on the pin  110  and the joint  56 , the reaction force  115  acting on the pin  110  and the joint  56  produces the counter moment  116 . As discussed above, the counter moment  116  counterbalances the overturning moment  78  acting on the top drive  40  caused by the offset center of gravity  70  of the top drive  40 . In this manner, forces (e.g., reaction moment  84 ) resulting from the overturning moment  78  and acting on the torque bushing  82  of the torque track system  80  may be reduced, thereby reducing premature and excessive wear on the torque bushing  82 . 
     While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.