Abstract:
A bracket and tension rod device to mount to atop-drive dolly to carry the weight of a sheave wheel assembly is disclosed. The invention is deployed by connecting the sheave wheel assembly to a rigid dolly arm with an adjustable tension rod to relieve a gooseneck from adverse tensile, compressive and bending forces from the movement of a wireline through the sheave assembly.

Description:
BACKGROUND OF INVENTION  
         [0001]    The present invention generally relates to a bracket for support of a wireline entry device adjacent a top-drive unit on an oil and gas drilling platform. More particularly, the present invention relates to a bracket or mounting system for supporting a wireline sheave assembly adjacent a top-drive of a drilling ship, platform, or rig to minimize stress on a gooseneck assembly and pressure control system.  
           [0002]    The majority of large oil rigs operating throughout the world are using top-drive units to speed the assembly of drill string and to permit rapid, almost continuous, drilling. Wireline operations required on deep wells using these expensive rigs can be a severe bottleneck if they cannot be carried out with the expediency and efficiency which is sought by all drilling contractors. To remedy the problem of inserting a wireline in a top-drive unit, a top-entry apparatus providing a safe and effective means of inserting and manipulating a wireline in a top-drive unit has been developed and is the subject of U.S. Pat. No. 5,735,351 hereby incorporated herein by reference for background of this technology.  
           [0003]    As the wells being drilled by top-drive units has increased and the depth of the wells being attempted by these top-drives has increased, the need for heavier and more robust wireline equipment has likewise be appreciated. Stringing wireline in well bore from above the top drive can be dangerous if the sheave and pulley system used is inadequate to support the weight of the increased wireline diameters (from {fraction (3/16)}″ to over {fraction ( 1 / 2 )}″) required to go to the depths currently being drilled. Accordingly, the need for robust sheave and pulley systems increases the stresses on the wireline entry gooseneck and the pressure control systems (i.e. packing) which is required to allow the wireline to be paid out to the tubular suspended below under possible pressures.  
         SUMMARY OF INVENTION  
         [0004]    Preferred embodiments of the present invention disclose improvements to a top entry access system that include a bracket and a load member connected to components of a top-drive unit (for example, a Varco top-drive) to prevent damage to top entry access system components. The brackets preferably include tie brackets for connecting with lower clevis hitches of load members. When employed, the systems act to relieve stresses in the gooseneck of the top entry access system that can result from the weight and wireline loads experienced from the weight of the sheave assembly. Preferably, the position of the load member is adjustable through the manipulation of a turnbuckle on the load member itself or the mounting locations at the tie bracket of the sheave wheel. Alternatively, the top entry access system can be used with slickline, coiled tubing, or fiber optic cable if wireline is not deployed. Furthermore, the load member of alternative embodiments to the preferred embodiment can be constructed as a single solid bar, a pair of solid bars connected in series with a turnbuckle therebetween, braided wire rope, a hydraulic ram, and a ball screw device. Additionally, the preferred embodiment includes a method for using the present invention in top-entry wireline (and other conduit) operations. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0005]    [0005]FIG. 1 is a perspective view drawing of a bracket assembly in accordance with a preferred embodiment of the present invention.  
         [0006]    [0006]FIG. 2 is a perspective view drawing of a tension rod assembly in accordance with a preferred embodiment of the present invention.  
         [0007]    [0007]FIG. 3 is a left side front perspective view drawing showing the bracket assembly of FIG. 1 and the tension rod assembly of FIG. 2 used in conjunction with a wireline top entry access system sheave assembly.  
         [0008]    [0008]FIG. 4 is a right side front perspective view drawing showing the bracket assembly of FIG. 1 and the tension rod assembly of FIG. 2 used in conjunction with a wireline top entry access system sheave assembly.  
         [0009]    [0009]FIG. 5 is a perspective view drawing of a bracket assembly in accordance with a second preferred embodiment of the present invention.  
         [0010]    [0010]FIG. 6 is a right side front perspective view drawing showing the bracket assembly of FIG. 5 mounted to a dolly of a top drive drilling apparatus.  
         [0011]    [0011]FIG. 7 is a perspective view drawing of a bracket assembly in accordance with a third preferred embodiment of the present invention.  
         [0012]    [0012]FIG. 8 Is a right side rear perspective view drawing showing the bracket assembly of FIG. 7 and a tension rod assembly used in conjunction with a wireline top entry access system sheave assembly.  
         [0013]    [0013]FIG. 9 is a left side rear perspective view of a bracket and tension rod assembly in accordance with a fourth preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0014]    Referring initially to FIG. 1, a bracket assembly  15  in accordance with a preferred embodiment of the present invention is shown. Bracket assembly  15  is preferably constructed from a rectangular extension arm  36  to which two gusset brackets  37  are laterally attached. Rectangular extension arm  36  and gusset brackets  37  are designed to slidably engage the lower gusset or strut of an existing top-drive dolly (shown as items  100   a, b  in FIGS. 3-4). An open channel in the rectangular extension arm  36  mates with the sloping support arm of the dolly (best seen in FIGS. 3 and 4). A notch  37   a  is provided on the upper edge of each gusset bracket  37  to clear obstructions of an upper gusset  102  (FIGS. 3-4). Hex bolts  38   a  are then inserted in holes provided in the upper edge of each gusset bracket  37  to form a cage around the adjacent interior edge of a lower gusset  104  (FIGS. 3-4). The angle of the holes in the end of the gusset brackets  37  approximates the slope of the dolly gusset adjacent thereto. Furthermore, while bracket assembly  15  is shown mounted to the left gusset  100   a  in FIGS. 3-4, is should be understood that the bracket assembly could just as easily be attached to the right gusset  100   a  if the preferences of the end user so desire.  
         [0015]    Referring again to FIG. 1, the bracket assembly is further secured to top drive assembly gussets by an optional L-shaped hanger assembly  20 . L-shaped hanger assembly  20  is connected to the bottom of the rectangular extension arm  36  by bolts  42   a  and on its lateral edge by bolts  42   b . Hanger assembly  20  is shown ribbed for strength-by strip  41  which prevents the hanger assembly from movement once in place. Additional L-shaped attachments  39  are connected to the hanger assembly  20  to allow the hanger to engage the upper and lower edges of the guard assembly on a standard top-drive assembly. Bolts  40   a  extend through hanger assembly  20  and compressively hold the top-drive guard by bracket  39   a  on the guard&#39;&#39;s lower edge. Likewise, bolts  40   b  extend through hanger assembly  20  and compressively hold the top-drive guard by bracket  39   b  on the guard&#39;&#39;s upper edge.  
         [0016]    Referring still to FIG. 1, an adjustment cap  43  is slidably engaged over the end of extension arm  36 . Adjustment cap  43  is configured to be slidably adjustable along the length of extension arm  36  with the use of slots  43   a  and securing bolts  38   b  and  38   c . Adjustment cap  43  further includes a clevis tie bracket  44  at its distal end. Tie bracket includes a plurality of holes  44   a  for adjustably mounting a clevis hitch (or a yoke end linkage) thereto. Sliding cap  43  thus allows an operator to fine-tune its position to achieve optimal position for clevis tie bracket  44 .  
         [0017]    Referring now to FIG. 2, a tension rod assembly  10  for connection with turnbuckle tie bracket  44  of FIG. 1 is shown. Tension rod assembly  10  includes an upper lug  52 , an upper adjustment rod  51 , a turnbuckle  50 , a lower adjustment rod  48 , and a lower lug  46 . Lower lug  46  is constructed as a clevis (or yoke linkage) so that it can be placed over the end of clevis hitch tie bracket ( 44  of FIG. 1) and secured with a shear pin and cotter pin assembly  45 . Lower adjustment rod  48  is then threaded into lower end of turnbuckle  50 . Upper adjustment rod  51  extends from upper end of turnbuckle  50  and terminates into upper lug  52 . Upper lug  52 , as shown more clearly in FIGS. 3-4, is connected to a Top Entry Access System sheave wheel  30  at any one of a plurality of mounting locations  54  with a shear pin. Turnbuckle  50  is preferably constructed such that the threads at one end are left hand threads so that rotation of turnbuckle  50  either extends or retracts adjustment rods  48 ,  51  simultaneously. Because connections between turnbuckle  50 , rods  48 ,  51 , and lugs  46 ,  52  are all threaded connections, hex jam nuts  47  can be used restrict movement thereof.  
         [0018]    Referring now to FIGS. 3-4 together, a sheave wheel assembly  30  is shown in conjunction with bracket assembly  15 , and tension rod assembly  10 . Sheave wheel assembly  30  generally includes a pair of large diameter sheave wheels  31   a ,  31   b  sandwiched between a pair of contoured plates  32   a ,  32   b . A gooseneck  34  connects sheave wheel assembly  30  to the top of a top drive assembly (not shown). Wireline cable  5 , extends from above sheave wheel  30 , underneath wheel  31   a , and over wheel  31   b  through pack off assembly and into gooseneck  34  to wellbore.  
         [0019]    For deep wells, sheave wheel assembly  30  can weigh as much as 1,500 lbs (680 kg.). If this much weight were allowed to rest solely on gooseneck  34 , substantial bending forces would be introduced into gooseneck  34  and pressure control assembly (not shown) which could damage assembly  34  and thereby increase the risk of failure of the pressure control system. Furthermore, the manipulation of wireline  5  during wellbore operations can move sheave assembly  30  and place considerable stresses on gooseneck  34 . Particularly, when large loads (as are often seen in deep water drilling operations) are pulled upward on wireline  5 , the stress to gooseneck  34  can be intense. When coupled with the lateral forces introduced into the sheave assembly by the movement and manipulation of a wireline  5  in sheave wheel assembly  30 , even more substantial damage could result to gooseneck  34  and pack assembly.  
         [0020]    The installation of the present bracket assembly  15  and tension rod  10  therefore allows the operator to adjust (by manipulation of turnbuckle  50 ) the pre-load to sheave assembly  30  to completely counterbalance the forces impinging on gooseneck  34 . These forces are then carried by the dolly extensions  100   a  and  100   b . Depending on loading conditions that are expected to be experienced by sheave assembly  30  and wireline S, the amount of pre-load in tension rod assembly  10  can be quickly and easily adjusted. While nomenclature suggests that tension rod assembly  10  is only capable of tensile loading, it should be understood by one skilled in the art that tension rod assembly  10  is capable of carrying both tensile and compressive loads. As such, an operator can adjust mounting points  54 ,  44   a  and turnbuckle  50  to adjust the load condition experienced by tension rod assembly  10 , and subsequently gooseneck  34 .  
         [0021]    Referring now to FIG. 5, an first alternative preferred embodiment of a bracket assembly  215  in accordance with the present invention is shown. Bracket assembly  215  includes an L-shaped hanger assembly  220 , a pair of gusset brackets  237 , and a square-shaped tie bracket  244 . Tie bracket  244  is angled from axis of bracket assembly  215 , is disposed upon a sliding adjustment arm  243 , and includes a plurality of mounting holes  244  for the attachment of a clevis hitch or yoke end linkage thereto. Sliding adjustment arm  243  in combination with bolts  238   a  and nuts  238   b  allows for the positioning and fine-tuning of tie bracket  244  by operator.  
         [0022]    Referring now to FIG. 6, bracket assembly  215  is shown attached to portions of a dolly  270  of a top drive drilling assembly (not shown). Because pre-existing dolly assemblies  270  vary by manufacturer, size, configuration, and style, the attachment scheme for bracket assembly  215  varies as well. Dolly  270  of FIG. 6 includes a pair of arms  272 ,  274 , each with an upper  276 , lower  278 , and middle  280  truss. Dolly  270  of FIG. 6 also includes a guard rail assembly  282  to prevent injury and to keep unwanted equipment clear. Bracket assembly  215  is installed by placing it over lower truss  278  of dolly arm  274  and bolting it in place. Because components of drilling rigs are often leased or purchased at high cost from differing vendors, it is important that permanent modifications are avoided whenever possible. As such, bracket assembly  215  is bolted into place upon lower truss  278  of dolly  274  without such modifications. After secured in place, a tension rod assembly  210 , similar to that of FIG. 2, is attached to the tie bracket  244  at a lower lug  246 . The length of tension rod assembly  210  can be adjusted by turning turnbuckle  250  to lengthen or shorten the length of an adjustment rod  248 .  
         [0023]    Referring now to FIG. 7, a second alternative preferred embodiment of a bracket assembly  315  in accordance with the present invention is shown. Like earlier embodiments, bracket assembly  315  includes an optional L-shaped hangar assembly  320 , a pair of gusset brackets  337 , a sliding adjustment cap  343  with a tie bracket  344  thereattached. Tie bracket  344  includes a plurality of holes  344  for receiving a clevis hitch or a yoke end linkage (not shown). Bracket assembly  315  is designed for applications upon top drive dollies where brackets  15 ,  215  of FIGS. 1, 5 will not fit because of space considerations. As with brackets  15 ,  215 , bracket  315  is bolted in place with a plurality of bolts and nuts  338  and adjustment cap includes slots  343   a  and bolts  338   a  to adjust and fine-tune positioning of tie bracket  344 .  
         [0024]    Referring now to FIG. 8, bracket assembly  315  of FIG. 7 is shown attached to a dolly assembly  370  of a top drive system (not shown). Top drive dolly  370  includes a pair of arms  372 ,  374 , each with an upper  376 , lower  378 , and middle  380  truss. Bracket assembly  315  is installed on dolly  370  by placing it over lower truss  378  of arm  374  and bolting it in place. Gusset brackets  337  surround lower truss  378  and are compressed securely against truss  378  when bolts  338  are tightened. A sheave wheel assembly is then located into position over the top drive unit (not shown) and a conduit  305  is disposed therethrough. Sheave wheel assembly includes a top wheel  331   a , a lower wheel  331   b , a pair of side plates  332  and a gooseneck assembly  334 . Bracket assembly  315 , together with a tension rod assembly  310 , help keep sheave wheel assembly  330  in place to prevent damage to gooseneck  334 . This is accomplished by connecting tension rod assembly  310  between sheave wheel assembly  30  and bracket assembly  315  by properly adjusting turnbuckle  350 , adjustment cap  343 , and mounting hole  344   a.    
         [0025]    Referring now to FIG. 9, a third preferred embodiment of a bracket assembly  415  in accordance with the present invention is shown. Bracket assembly  415  shown is one designed for attachment to “bailes” of a top drive assembly (not shown). The bailes (not shown) are large, bar-shaped links that act like links of a chain between the lifting hook of the derrick not shown and the top drive assembly. This arrangement would be beneficial in situations where the drilling operation company desired that nothing be attached, even removably, to the dolly  270  of the top drive assembly. Bracket assembly  415  includes a main bracket  460 , a pair of tension rod assemblies  410 , a pair of bail clamps  465 , and a sheave wheel assembly  430 .  
         [0026]    Sheave wheel assembly  430  shown in FIG. 9 is departure from that shown in FIGS. 3, 4, and  8  in that sheave wheel assembly  430  is of a compact configuration. Instead of sheave wheel assembly  430  having two large-diameter sheave wheels, assembly  430  has an upper sheave wheel  431   a  and a plurality of small diameter rollers  431   b  arranged in an arcuate pattern to simulate the curvature of a sheave wheel. It is important to note that bracket assembly  415  of FIG. 9 (or bracket assemblies  15 ,  215 , and  315  of the preceding Figures) is capable of being used with either a standard sheave wheel (for example, item  330  of FIG. 8) or the compact sheave wheel assembly  430  of FIG. 9.  
         [0027]    Main bracket  460  of bracket assembly attaches to sheave wheel assembly  430  at any one of a plurality of holes  432 . Connection methods between sheave wheel assembly  430  and main bracket  460  are any number of those currently available to those skilled in the art, but preferably is of a shear-pin design. From main bracket  460 , two tension rod assemblies  410  attach at a plurality of holes  462  upon bracket  460  and extend downwardly until they each terminate at a ball clamp  465 . Bail clamps  465  are analogous to tie brackets  44 ,  244 , and  344  of FIGS. 1, and  4 - 8  In that they allow the positional adjustment of the lower ends of tension rod assemblies  410 . Ball clamps are preferably constructed as simple pipe clamps but may be of any design that is capable of securely fastening to the bailes. Bail clamps  465  may be adjusted along the bailes in a manner similar to the adjustment of adjustment caps  43 ,  343  and adjustment arm  243 . With clamps  465  securely tightened upon bailes (not shown), a turnbuckle  450  is then adjusted on each tension rod assembly  410  to properly position and resist movement of sheave wheel assembly  430 . The movement of sheave wheel assembly is restricted to prevent seal elements contained within a gooseneck  434  at its lower end from being damaged by changes in loading that might otherwise deflect sheave wheel assembly  430 .  
         [0028]    While preferred embodiments of the present invention are shown, it should be understood that alternatives not shown still fall within the spirit and scope of the invention. Generally, various changes in the size, shape, and materials, as well as the details of the illustrated operation and construction may be made. More particularly, different embodiments for the bracket assemblies  15 ,  215 ,  315 , and  415  and tension rod assemblies  10 ,  210 ,  310 , and  410  may be employed. Specifically, the actual design and configuration of mountings for components of the present invention will differ from one installation to another because of variables including, but not limited to, the make and model of the top-drive assembly to be installed upon, customer preferences, and regional safety requirements. It should be understood that the preferred embodiments shown are capable of being adapted and modified to accommodate a wide array of top drive assemblies. Furthermore, it should be understood that features of the present invention may be integrated into the design of top drive assemblies (contrasted from the aftermarket installation herein disclosed) without departing from the spirit of the invention.  
         [0029]    Finally, in some installations, tension rod assemblies  10 ,  210 ,  310 , and  410  may be constructed of tension-only members (i.e. wire rope) or real-time adjustable load members (i.e. hydraulic piston ram or mechanical ball or screw) without departing from the spirit and scope of the invention. Such a real-time adjustable load members would enable an operator (or an automated system) to continuously adjust the load on tension rod assemblies  10 ,  210 ,  310 , and  410  for various downhole and wirelines conditions to optimize performance of Top Entry Access System and sheave wheel  30 ,  330 , and  430  assemblies. It should also be understood that a system in accordance with a preferred embodiment of the invention will be capable of allowing access of various forms of elongate conduits into a wellbore. Examples of said conduits include, but are not limited to, wireline, fiber optic cable, slickline, and coiled tubing.