Patent Publication Number: US-6705414-B2

Title: Tubular transfer system

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a tubular transfer system for a drill rig, and in particular, to a tubular transfer system that moves the tubulars between a horizontal position on the deck and a vertical position at the rig floor entry. 
     2. Description of Related Art 
     Drill rigs have utilized several methods for transferring tubular members from a pipe rack adjacent to the drill floor to a mousehole in the drill floor or the well bore for connection to a previously transferred tubular or tubular string. The term “tubular” as used herein includes all forms of drill pipe, drill collars, casing, liner, bottom hole assemblies (BHA), and other types of tubulars known in the art. Conventionally, drill rigs have utilized a combination of the rig cranes and the traveling system for transferring a tubular from the pipe rack to a vertical position above the center of the well. The obvious disadvantage with the prior art systems is that there is a significant manual involvement in attaching the pipe elevators to the tubular and moving the pipe from the pipe rack to the rotary table. This manual transfer operation in the vicinity of workers is potentially dangerous and has caused numerous injuries in drilling operations. Further, the hoisting system may allow the tubular to come into contact with the catwalk or other portions of the rig as the tubular is transferred from the pipe rack to the drill floor. This can cause damage to the tubular and may affect the integrity of the connections between successive tubulars in the well. Finally, past systems have only been able to transfer single joints of pipe or casing. 
     In response to the disadvantages of a conventional handling system, other prior art apparatuses for gripping a drill pipe and transferring the pipe from a horizontal position on the pipe rack to a vertical position above the drill floor have been developed. Some of these systems allow the pipe to be handled without the necessity of manual interaction in grasping the pipe or transferring the pipe to the well. One of these apparatuses is disclosed in U.S. Pat. No. 3,633,771 to Woolslayer, et al. Woolslayer teaches a drill string that is moved by a strongback having hydraulic grasping jaws. This apparatus is mounted to the drilling platform and is centered in the V-door of the rig. 
     Another apparatus is disclosed in U.S. Pat. No. 4,834,604 to Brittian et al. Brittian teaches a strongback that is connected to a one piece boom with the boom being mounted on a base located adjacent the rig and operating directly through the V-door of the rig. The strongback transfers pipe through the V-door to a vertical position and raises or lowers the pipe so that a connection between the pipe and the drill string can occur. 
     Yet another apparatus is disclosed in U.S. Pat. No. 5,458,454 to Sorokan. Sorokan discloses a pipe handling method for moving tubulars from a horizontal position on a pipe rack adjacent to the well bore to a vertical position over the center of the well by using a bicep and forearm assembly and gripper head for attachment to a tubular. The tubular is moved along or close to the conventional path of the tubular utilizing known cable transfer techniques so as to allow access to the drill floor through the V-door of the rig. More recent designs have utilized a deck transfer system complete with a conveyer to move individual joints from the deck area to the rig floor entry. 
     The disadvantages of the prior art are several: a substantial amount of human physical contact with tubulars and lifting devices is required; the process for transferring tubulars is lengthy, costing more in rig time and total operational spread cost; the condition of a drilled hole deteriorates with time and may cause damage to the well; the space on the rig floor is limited, thus limiting the ability to conduct simultaneous operations such as drilling and picking up tubulars from the deck; and there are safety risks associated with a crane interface with the rig floor. All of the previous systems have only been able to pick up a single length of drill pipe, which is generally 30 feet long, or a single length of casing, which is generally 40 feet long. 
     Ideally, one would like to have a horizontal to vertical tubular transfer system that allows multiple segments of tubulars to be assembled on the deck, prior to being moved to the rig floor, then stored in a pipe rack until needed by the drilling operation. The system should minimize required manual contact with tubulars while maintaining the simplicity of the drilling operation. The tubular transfer system should also be relatively lightweight, and low-cost. The system should also increase the efficiency of the tubular handling operation. 
     SUMMARY OF THE INVENTION 
     The present invention is a method and apparatus for transferring tubular stands, which include more than one length of connected tubulars, between a substantially horizontal position on the catwalk and a substantially vertical position at the rig floor entry. In one embodiment of the invention, the drilling rig is a cantilever jack-up in which the cantilever beams are of sufficient length that three joints of Range II drill pipe (nominal 30 ft lengths) can be stored when assembled together; such a length of three drill pipes is normally called a stand. In this embodiment, individual joints of drill pipe are transferred from the main deck pipe racks to the cantilever pipe rack and then to a stand make-up/break-out machine, also called a bucking machine. The bucking machine stabs the drill pipe connections and makes them up to the correct torque. The drill pipe stand is then transferred from the bucking machine to a stand storage area (pipe rack) or to a trolley pick-up area. When additional stands are needed by the drilling operation, a trolley is moved into position over the trolley pick-up area to retrieve stands previously made up. The stands are clamped to the trolley and the trolley is moved from a substantially horizontal position to a substantially vertical position at the rig floor entry. A vertical pipe racking machine permanently located in the derrick transfers the stands to the well center where it can be picked up by the traveling equipment or to the vertical pipe rack in the derrick (or set back) where it can be stored until needed by the drilling operation. The stand is made up to the drill string already in the hole and the stand is run into the hole. This operation is repeated until all of the drill pipe required by the drilling operation has been installed in the hole. The operation can also be reversed to remove stands from the rig floor entry and break out the stands in a horizontal position on the cantilever pipe rack deck. The description above relates to drill pipe but exactly the same process can be applied to casing, which normally comes in 40 ft lengths and therefore a stand of casing in this embodiment will consist of two joints of pipe also made up by the bucking machine on the cantilever pipe rack deck. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIGS. 1A and 1B are perspective views of a jack-up rig in accordance with an embodiment of the invention. 
     FIG. 2 is a perspective view of the cantilever and vee-door of FIGS. 1A and 1B in accordance with an embodiment of the invention. 
     FIG. 3 is a cut away perspective view of the power tongs on the bucking machine shown in FIG. 2 in accordance with an embodiment of the invention. 
     FIG. 4A is a perspective view of the cantilever with the trolley in a half-way-down position in accordance with an embodiment of the invention. 
     FIG. 4B is a perspective view of the cantilever with the trolley lowered to the horizontal position in accordance with an embodiment of the invention. 
     FIGS. 4C,  4 D,  4 E and  4 F are end views of the trolley in the various states of a pick-up operation in accordance with an embodiment of the invention. 
     FIG. 4G is a perspective view of the cantilever showing the trolley approximately halfway between the horizontal and vertical position in accordance with an embodiment of the invention. 
     FIGS. 4H and 4I are side views of the trolley and the track in accordance with an embodiment of the invention. 
     FIGS. 5A,  5 B,  5 C and  5 D, are top perspective views showing the inside of the derrick in accordance with an embodiment of the invention. 
     FIG. 6 is a bottom perspective view showing the inside of the derrick in accordance with an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIGS. 1A and 1B, perspective views of a jack-up rig  100 , in accordance with an embodiment of the invention, is illustrated. The jack-up rig in FIG. 1A is shown in a floating mode. The jack-up rig has independent legs  110 ,  120 ,  130  that are positioned in proximity to a respective corner of the triangular platform  140 . The independent legs  110 ,  120 ,  130  are extended through the platform  140  to the floor of the body of water over which the platform is located. Once the independent legs  110 ,  120 ,  130  have made contact with the floor, the platform  140  can then be “jacked-up” above the surface of the water. This method of jacking-up the platform is well known in the art. While the invention is described in regard to an off-shore jack-up rig, the invention is not limited to any particular type of drilling rig, nor is it limited to drilling rigs in particular. The invention may be used anywhere a tubular transfer system is needed without departing from the scope of the invention. For example, the invention may be used for land rigs, production and drilling platforms, tender assist rigs, and drilling barges. 
     Once the platform  140  has been jacked-up, the cantilever  150  can be extended out over the water as shown in FIG.  1 B. The upper surface of the platform  140  supports a helipad  155 , and living quarters  160 ,  170 . The cantilever comprises two beams  150  which support at their aft end a substructure on which is mounted the drill floor. In the presently preferred embodiment, the drill floor is capable of lateral movement on the substructure. The cantilever is extended and the drill floor is moved laterally on the substructure so that the rotary table can be placed in a precisely pre-selected location aft of the jack-up hull transom. In an alternative embodiment the drill floor remains stationary on the substructure and the entire cantilever is moved laterally. In the current design, the living quarters were mounted to the sides of the bow leg, rather than being positioned aft, as they are in previous designs. This change allowed the cantilever to extend all of the way forward to the bow leg when in the stowed position. As result it is much longer than prior art cantilevers which terminated at the aft side of the quarters house. This increased cantilever length also increased the cantilever pipe rack length to more than the 90 feet required to accommodate a stand of three connected drill pipes. Prior art cantilever pipe racks generally are not long enough to accommodate a stand of drill pipe. This increased cantilever pipe rack length pointed to a need to be able to move assembled stands of pipe or casing from a horizontal position on the cantilever pipe rack to a vertical position at the vee door entrance. 
     Referring now to FIG. 2, a cut away perspective view of the cantilever  150  of FIGS. 1A and 1B in accordance with an embodiment of the invention is illustrated. A deck or rig crane  205  is used to place single pieces of drill pipe or casing called “tubulars”  210 ,  215  in the cantilever staging area  220 . Once the individual tubulars have been prepared for make-up, the deck or rig crane  205  transfers the tubulars  210 ,  215  to the bucking machine  225  for assembly of the tubulars into a stand. In this embodiment, the bucking machine  225  is located on the catwalk  230 . The bucking machine  225  aligns, stabs, and makes up the connection to the correct torque value. After make-up, the stand is transferred from the bucking machine  225  to a stand storage area  235  on the cantilever pipe rack  150  using the deck or rig crane  205 . Alternatively, the stand could be placed directly into the trolley pick-up area  240  to be picked-up by the trolley  245 . 
     All of the stands that will be needed for a section can be made-up prior to the drilling operation or the make-up process can be ongoing while the drilling operation is being conducted. By making-up the tubulars into stands before they are needed by the drilling operation, the process for make-up of the stands is taken out of the critical path of the drilling operation. Because the number of make-ups is reduced by making up the stands prior to the drilling operation, the time required to run the stands into the hole is reduced. Depending on the length of the cantilever  150 , as well as the length of the tubulars  210 ,  215  double, treble, or more sections of tubulars can be made up in the horizontal position before being transferred to the derrick  180 . The terms “horizontal” and vertical” as used herein are intended to encompass minor variations from perfectly horizontal and perfectly vertical, respectively. One with skill in the art will understand that these terms refer to approximate positions relative particular components of the drill rig. 
     The length of the cantilever  150 , as well as the height of the derrick  180  can be varied depending on the length of the stands  255 ,  260  desired. In one embodiment of the invention, the dimensions of the cantilever  150  and the derrick  180  are such that a stand of approximately 90 feet can be accommodated and made up on the cantilever in the horizontal position and then transported to a vertical position in the derrick  180  in. A pair of power tongs  250  are utilized by the bucking machine  225  to make-up or break-out a tubular stand. These power tongs  250  are commonly known in the art. 
     Referring now to FIG. 3, a cut away perspective view of the power tongs  250  shown in FIG. 2 in accordance with an embodiment of the invention is illustrated. The jaws  315 ,  320 ,  325 ,  330  clamp down on the tubulars  330 ,  335  to mate the male end  340  of tubular  335  with the female end  345  of tubular  330 . The jaws turn the tubulars in the direction of the arrows  305 ,  310  to screw the tubulars  330 ,  335  together and torque them to the appropriate value. The process can be reversed to break out the connection. 
     Referring now to FIG. 4A, a perspective view illustrates the cantilever with the trolley  245  in a halfway down position in accordance with an embodiment of the invention. Two tubular stands  405 ,  410  are placed in the trolley pick-up area  240  prior to the trolley  245  traveling down to the horizontal position. At the lower and upper ends of the trolley  245 , a pair of wheels  415  are attached. The wheels  415  travel along a track  420  that extends from the lower end of the trolley travel on the cantilever  150  to the upper end of trolley travel on the derrick  180 . The trolley  245  is attached to a drive means such as a cable winch  450  that is used to winch the trolley  245  up and down. The cable winch  450  could also be any drive means capable of moving the trolley  245  along the track  420  and is not limited to a cable winch. For example, the drive means could be a rack and pinion or a sliding mechanism in the track  420  that engages the trolley  245  to move it up and down. 
     Referring now to FIG. 4B, a perspective view illustrates the cantilever with the trolley  245  lowered to the horizontal position in accordance with an embodiment of the invention. In the position shown, the trolley can pick up stands of tubulars from the trolley pick-up area  240 . The number of stands picked up can vary depending on the design of the trolley  245 . For example, with relatively small diameter tubulars, a higher number of stands may be picked up, and for relatively large diameter tubulars, a smaller number of stands may be picked up. One with skill in the art will recognize that any number of stands may be picked up at any given time without departing from the scope and spirit of the invention. 
     Referring now to FIGS. 4C,  4 D,  4 E and  4 F, these drawings illustrate end views of the trolley  245  in the various states of a pick-up operation in accordance with an embodiment of the invention. In FIG. 4C, the trolley  245  is shown in the horizontal position as the pick up of the tubular stands  405 ,  410  begins. Before the trolley  245  is lowered to the horizontal position, the tubular stands  405 ,  410  are placed in the trolley pick up area such that they nest in a cut away in the push-up arms  435 . Push-up arms  435  are located at a plurality of locations along the length of the tubular stands  405 ,  410  for pushing the tubular stands  405 ,  410  up into the trolley  245 . FIG. 4D shows the tubular stands  405 ,  410  as they are pushed up into the trolley  245 . At this point in the operation, the fingers  425 ,  430  are still in a retracted position. Once the tubulars have been pressed into place by the push-up arms  435 , the fingers  425 ,  430  extend downward and swing inward from the stored position as shown in FIG.  4 E. Once the fingers  425 ,  430  are under the tubulars as shown in FIG. 4E, the fingers  425 ,  430  are then lifted up to hold the tubulars  405 ,  410  in position on the trolley  245  and the push-up arms are lowered as shown in FIG.  4 F. Once the tubular stands  405 ,  410  are clamped into place by the fingers  425 ,  430  on the trolley  245 , the cable  450  is hoisted in an upward direction such that the trolley  245  moves along the track going first up the incline  440  (illustrated in FIG. 4G) such that the trolley  245  is transferred from a substantially horizontal position at the trolley pick up area into a substantially vertical position in the derrick  180 . 
     The shape and structure of the trolley  245  has been disclosed and described in reference to FIGS. 4C,  4 D,  4 E, and  4 F. However, the trolley is not required to have the structure disclosed. Any trolley capable of retrieving a tubular and moving along a track may be used. The particular grasping means disclosed can also be varied without departing from the scope of the invention. 
     Referring now to FIG. 4G, a perspective view of the cantilever illustrates the trolley  245  approximately halfway between the horizontal and vertical position in accordance with an embodiment of the invention. FIG. 4G illustrates that the tubulars have been picked up and that there are no longer any tubulars in the trolley pick up area  240 . Once the trolley  245  is clear of the trolley pick up area  240 , another set of tubular stands may be placed in the trolley pick up area  240  either by using the deck or rig crane  205  or manually moving the stands to place them in the cut-out of the push-up arms  435 . 
     Referring now to FIGS. 4H and 4I, side views of the trolley  245  and the track  420  in accordance with an embodiment of the invention are illustrated. FIG. 4H shows the trolley in transit between the horizontal and vertical positions. FIG. 4I shows the trolley in a vertical position ready for the tubular stands to be removed from the trolley by a vertical pipe racking machine. 
     Referring now to FIGS. 5A,  5 B,  5 C, and  5 D, top perspective views inside the box derrick  180  in accordance with an embodiment of the invention are illustrated. FIG. 5A shows the trolley in a vertical position before the tubular stands  405 ,  410  are released from the trolley  245 . FIG. 5B shows a vertical pipe racking machine  505  as it attaches to the tubular  410  before the fingers  430  are released and retracted by the trolley  245 . 
     FIG. 5C shows the fingers  430  in a retracted position and the tubular stand  410  in transit between the trolley  245  and the well center. Provided that the prior tubular  510  has been run into the well far enough, the tubular  410  may be attached to the prior tubular  510  with traveling equipment  515 , as is commonly known in the art, so that it may also be run into the well. However, if drilling is slow and the prior tubular  510  is not low enough for the tubular stand  410  to be installed at the time that the vertical pipe racking machine  505  removes the tubular stand  410  from the trolley  245 , then the vertical pipe racking machine  505  can instead place the tubular stand  410  on the vertical pipe rack  520  in one of the slots shown. In this manner, a number of tubulars stands  525  can be held in the vertical pipe rack  520  for use in the event that the horizontal to vertical tubular transfer system malfunctions or is delayed for whatever reason. Thus, the horizontal to vertical transport system is kept out of the critical path of the operation except when it is in a vertical position at the rig floor entry. This system provides a more efficient and faster tubular handling operation then has been available in the past. 
     FIG. 5D shows the tubular stand  410  in a vertical position over the well center. Once the tubular stand  410  is screwed into the previous stand and torqued to the appropriate value by the tubular tong equipment  511 , the vertical pipe racking system then retrieves the tubular stand  405  from the trolley  245  and either places it in a position so that it can be run into the well or places it in the vertical pipe rack  520  if the drilling operation is not ready for an additional tubular stand. Once the tubular stand  405  is removed, the trolley  245  can then be transported back down to the horizontal position by unwinding the cable winch  450  attached to the top of the trolley  245  to allow the trolley  245  to roll back down into the horizontal position. The operation can then be repeated with another set of stands. One with skill in the art with understand that the operation described above can simply be reversed to remove stands from the hole and break them out on the platform in a horizontal position using the breakout machine  250 . This system significantly speeds up the process. 
     Referring now to FIG. 6, a bottom perspective view inside the box derrick  180  in accordance with an embodiment of the invention is illustrated. FIG. 6 shows the drill floor  190  as well as the tracks  420  on which the trolley  245  moves up and down between the horizontal and vertical position. The vertical pipe racking system  502  and traveling equipment  515  are also illustrated. 
     Those skilled in the art should understand that the previously described embodiments of the tubular transfer system are submitted for illustrative purposes only and other embodiments thereof are well within the scope and spirit of the present invention. Although the present invention has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form. For example, changes to the design of the trolley and pick-up mechanism can be made. Other types of tubulars than those disclosed could also be used. Further, the pipe handling means inside the box derrick may also be varied without departing from the scope of the invention.