Abstract:
A racking assembly for receiving and storing at least one pipe. The racking assembly comprises a set back assembly including a selectively rotatable member having a plurality of radial slots sized for receiving a portion of the pipe(s) in sliding engagement, and a base for supporting the pipe(s). The base is coupled to the selectively rotatable member so as to permit mutual rotation. A barrier is located about a peripheral edge of the base, such that the setback assembly rotates relative to the barrier. The barrier is arranged to prevent the pipe(s) from moving radially from the base. The barrier has a gap sized to permit selective lateral movement of the pipe(s). Mutual rotation of the selectively rotatable member and the base permit alignment of the gap and a selected slot of the selectively rotatable member, and thus permits the pipe stands to be moved laterally into the setback assembly.

Description:
This is a divisional of U.S. application Ser. No. 12/364,230, filed Feb. 2, 2009, now abandoned, which claims the benefit of U.S. Provisional Application Ser. No. 61/006,809, filed on Jan. 31, 2008. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to the manipulation and control of pipe stands used in for instance the petrochemical industry. In particular, the invention relates to the control of pipe stands, as they are disengaged from drill strings on extraction from a well bore. 
     BACKGROUND OF THE INVENTION 
     On the completion of the drilling of a well bore, which maybe up to several hundred metres deep, the removal of pipes can be a time consuming exercise. Further, as the pipes are of a considerable size, for instance up to 200 mm (9⅝″) in diameter and up to 9.1 metres (30′) long these pipes also present problems in handling in an efficient and safe manner. This is particularly so for applications where a pipe stand (that is 3 pipes joined) are stored, and so having a section 27.4 metres (90′) in length. 
     As the pipes are withdrawn, one method of controlling and storing the pipe stand is to individually lift them into a rack as the drill string is extracted. However, the time taken for each pipe to be moved in such a manner, can be a considerable. Further it is a logistically difficult exercise to both lift and move a pipe into a rack particularly for the first pipe within the rack as the lateral distance to be moved maybe significant. It follows that during this activity accidents may occur during replacement within the rack and therefore present a safety problem. 
     SUMMARY OF INVENTION 
     It is therefore an object of the present invention to improve either speed of handling or safety, as compared to systems of the prior art. 
     In a first aspect the invention provides a racking assembly for receiving and storing at least one pipe, the racking assembly comprising a setback assembly including a selectively rotatable member having a plurality radial slots sized to receive a first portion of the at least one pipe in sliding engagement, and a base placed distal from the selectively rotatable member and coupled thereto so as to permit mutual rotation, said base arranged to support the at least one pipe on a support face of said base; a barrier located about a peripheral edge of the base, such that the setback assembly rotates relative to the barrier, said barrier arranged to prevent the at least one pipe from moving radially from said base, said barrier having a gap sized to permit selective lateral movement of the at least one pipe; wherein mutual rotation of the selectively rotatable member and the base permit alignment of the gap and a selected slot of said selectively rotatable member, and so permitting the pipes stands to be moved laterally into said setback assembly. 
     In a second aspect the invention provides a method of receiving and storing at least one pipe, the method comprising the steps of: providing a setback assembly, said setback assembly including a selectively rotatable member with a plurality radial slots and a base placed distal from the selectively rotatable member and coupled thereto so as to permit mutual rotation; engaging the pipe in any of said slots and; moving the pipe laterally so as to slide along said slot and be placed on said base. 
     In a third aspect the invention provides a guide assembly for receiving a pipe and moving said pipe to an outlet position, the assembly comprising a first and second support assembly for engaging the pipe, said assemblies in spaced relation to engage distal portions of said pipe; said support assemblies arranged to rotate as a single entity so as to rotate the pipe from an engaging position to the outlet position. 
     In a fourth aspect the invention provides a method for receiving a pipe and moving said pipe to an outlet position, the method comprising the steps of: engaging the pipe with a first and second support assembly, said assemblies in spaced relation to engage distal portions of said pipe; rotating said support assemblies and so rotating the pipe from an engaging position to the outlet position. 
     In a fifth aspect the invention provides a pipe delivery system comprising a base to which pipes are delivered; a support block for supporting a plurality of pipe; said base having at least one slot sized to allow the support block to project from or retract into said base, said slot further sized to prevent said pipe to pass there through; wherein the support block is arranged to move along said slot, projecting from said slot with said pipe and to selectively retract below said base so as to position the pipe on said base. 
     In a sixth aspect the invention provides a method of delivering a plurality of pipes to a base, the method comprising the steps of: supporting the plurality of pipes on a support block; projecting the support block from a slot in said base; moving the support block along said slot whilst projecting from said slot with said pipes and; selectively retracting below said base so as to position the pipes on said base. 
     In one aspect, the invention provides for a more direct lateral placement of the pipe or pipe stand, instead of, for instance, a lift and drop system. This may increase the speed of positioning; as well avoid injury during the dropping step. 
     In a further aspect the lateral movement or delivery of the pipe into the rack may be provided as array of pipes (or pipe stands) with the delivery system moving several pipe stands in one movement into the rack in a controlled environment. 
     It will be noted that the invention is equally applicable to the storage of both pipes and pipe stands. Accordingly, these terms may be interchanged without limiting the scope of the invention, unless specifically identified as such. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       It will be convenient to further describe the present invention with respect to the accompanying drawings to illustrate possible arrangements of the invention. Other arrangements of the invention are possible and consequently the particularity of the accompanying drawings is not to be understood as superceding the generality of the preceding description of the invention. 
         FIGS. 1A to 1C  show various views of a setback assembly according to one embodiment of the present invention; 
         FIGS. 2A and 2B  show various views of storage racks according to a further embodiment of the present invention; 
         FIGS. 3A and 3B  show a guide assembly according to a further embodiment of the present invention; 
         FIGS. 4A to 4D  show various views of a racking assembly according to a further embodiment of the present invention; 
         FIGS. 5A to 5F  show a delivery system according to a further embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A ,  1 B and  1 C show a racking assembly designed to receive and store pipes, or pipe stands, as they are removed from a well center. Drill strings comprise individual pipe stands which are connected as the bore is drilled deeper in order to meet the exploration or hydrogen extract objective. On completion of the objective the drill string will be removed with the pipe stands each disconnected from the drill string as each pipe stand fully emerges from ground, or water in the case of drilling from a ship. 
     Each pipe can be up to 6 meters (30′) long and up to 200 mm (9⅝″) in diameter, with a pipe stand typically relating to 3 pipes connected in series and so 3 times the length. Further the wall thickness of the pipe may be considerable such as up to 25 mm and therefore each pipe stand will be of significant weight. The target rate of disengaging each pipe stand and storing ready for further withdraws of the drill string is 60 stands an hour, or one minute per stand. It will be appreciated that this is a significant rate and may not be achieved by many, if any, existing systems. Accordingly the present invention seeks to accelerate the rate of processing of the pipe stands and therefore includes features arranged to either accelerate such processing or maintain acceptable rates at far higher levels of safety than are currently available according to the prior art. 
       FIGS. 1A to 1C  show one embodiment of the present invention. A racking assembly  5  includes a fingerboard assembly  10  at the top of the racking assembly  5  with a base assembly  15  at the bottom. In this embodiment the racking assembly includes two parallel setback assemblies made up of a fingerboard  25   a ,  25   b  corresponding to a base  20   a ,  20   b . Each setback assembly acts independently in this case and in fact the invention requires only one such setback assembly with the second setback assembly increasing the overall storage capacity of the device. 
     The fingerboard  25   a ,  25   b  is connected to the corresponding base  20   a ,  20   b  by a vertical shaft  45   a ,  45   b . The shaft ensures that each fingerboard and base rotates together, that is mutual rotatability. 
     The racking assembly  5  further includes a pair of racker arms  35 ,  40  which engage an upper and lower portion of a pipe stand (not shown) and deliver the pipe stand to the fingerboard and base. In this embodiment a guide assembly, in this case slot machine assembly  30 ,  32  are included however the racking assembly according to the present invention does not require the intermediate guide assembly. 
     For convenience the racker arms  35 ,  40  are mounted to a guide assembly shaft  50 . In a further embodiment the racker arms may be conveniently place elsewhere and in fact for further convenience additional pairs of racker arms may be included so as to further engage pipe stands as they become available, subject to the speed and availability of the racking assembly to accommodate such pipe stands, at a faster rate. 
     Further shown in this embodiment are fingerboard pushers  26   a ,  26   b  which act to facilitate positioning of the pipe stands once engaged, should this be required.  FIGS. 2A and 2B  show setback assembly, and in particular the fingerboard assembly  10  and base assembly  15  in greater detail. The fingerboard assembly  10  comprises a fingerboard plate  11  with the two fingerboards  25   a ,  25   b  rotatable within the plane of fingerboard plate  11 . 
     Further included is a recess in which the top guide assembly  30  is located with an inlet  65  through which the upper part of the pipe stand enters the guide assembly as manipulated by the upper racker arm  35 . As will be explained in greater detail later, the guide assembly  30  engages the pipe stand as it enters the inlet  65  and rotates so as to deliver the pipe stand to a slot  60  which has been rotated to correspond to the outlet  75 . As will further be discussed later, in this embodiment a pipe delivery system such as a cam lifter  55  may act to facilitate the more rapid placement of each pipe stand by the guide assembly placing several pipe stands on the cam lifter  55  before said pipe stands are delivered as an array of pipes into the corresponding slot  60 . 
       FIG. 2B  shows the base assembly  15  having two bases  20   a ,  20   b  which correspond to the aforementioned fingerboards  25   a ,  25   b . As the pipe stand is delivered to the racking assembly the bottom portion of the pipe stand is simultaneously engaged by the lower racker arm  40  and delivered to the bottom guide assembly  32 . The top and bottom guide assemblies are synchronized to rotate together to deliver the pipe stand to, in this embodiment, a cam lifter  55  for placement within the assembly. A key feature of the racking assembly according to the present invention is the base arrangement whereby a barrier  21   a ,  21   b  is positioned about an edge of the base. The barrier is fixed relative to the base such that the base will rotate maintaining the barrier in the same position. The barrier  21   a ,  21   b  includes a gap  90  though which the lower portion of a pipe stands may pass. Thus the racking assembly according to the present invention does not require a “lift and drop” placement such as that known in the prior art. A racking system is disclosed in WO02/18742, the contents of which are incorporated herein. This system requires each pipe stand to be lifted and then dropped into a corresponding lower fingerboard so as to be secured. Further the lifting and lowering is achieved by racker arms which must be controllable to a sufficient degree so as to correspond to the slot within the bottom fingerboard. Not only is it time consuming. the lifting and lowering may involve a safety issue given the weight of each pipe stand and the pressure of maintaining a steady storage rate of pipe stands. 
     By comparison, the racking assembly according to the present invention merely slides each pipe into place and thus eliminating the “lift and drop” approach of the prior art. Each pipe stand or array of pipe stands located within individual slots of the top fingerboard  25   a ,  25   b  are maintained in position by the fingerboard plate  11  at the top and by the barrier  21   a ,  21   b  at the lower portion. A further advantage includes the ease of manufacture of the base as compared to a lower fingerboard according to the prior art, having several slots formed to accommodate the respective pipe stands. 
       FIGS. 3A and 3B  show respective detail views of the upper guide assembly  30  and lower guide assembly  32  according to a further aspect of the present invention. The guide assembly  30 ,  32  acts as an intermediary placement mechanism. It will be appreciated that the guide assembly  30 ,  32  may also be incorporated into different racking assemblies. Whilst there is distinct advantage in the use of the racking assembly  5  with the guide assembly  30 ,  32 , advantage can also be gained by using the guide assembly in other systems. Equally the racking assembly  5  also has advantage without the guide assembly  30 ,  32  compared to the prior art which of course can benefit further by combining these two key elements. 
       FIG. 3A  shows the top guide assembly  30  having a pipe guide  72  which is shaped to guide the shaft of the pipe stand directly below the spigot head of the pipe. Not shown are latches that act to keep the pipe stand in place, and so acting as a mechanical lock, for added prevention of the pipe slipping out of position. Other types of guidance assemblies will be appreciated and the invention is not restricted to this particular type as shown for this embodiment. The pipe stand enters the void  95  through a gap  65  and once engaged with the gripper  72  will rotate about bearing  100  until the pipe stand corresponds with the outlet gap  70 . In this embodiment the fingerboard has been rotated so as to present a vacant slot  60  to receive the pipe stand once engaged. 
       FIG. 3B  shows the bottom guide assembly  32  which in this case includes a pipe gripper  82  with a support plate  80 . The pipe stand is lifted onto the support plate  80  by the racker arms and then subsequently engaged by the upper gripper  72  and lower gripper  82  so as to control the rotation of the pipe stand by the guide assembly. Slot  81  is further provided, in this embodiment, to assist with the eventual placement of the pipe stand into the setback assembly, and corresponds to slot  215  in the base, as shown in  FIG. 5B . The lower guide assembly  32  includes a further bearing  105  which assists with rotation under controlled conditions and corresponds to the rotation of the upper guide assembly  30 . As the pipe stand is rotated the lower of the pipe stand is placed upon in this embodiment a delivery system (not shown) which will be described in further detail later. The guide assembly according to the present invention does not require a delivery system such as that shown in  FIG. 3B . However, in combination with the delivery system according to a further aspect of the present invention provides further advantage rather than using other processes according to the prior art. Thus on rotation of the pipe stand, the pipe stand may enter through gap  90  so as to be placed on the base  20   a.    
     The use of racker arms for engaging a pipe stand is known and is a useful way of engaging a pipe or pipe stand during detachment from the drill string. After detachment of the pipe or pipe stand from the string, the racker arms may also be used for placement, albeit an inaccurate, given the size and weight of such an object. To better control the placement and storage of the pipe stand, the guide assembly, has fewer degrees of freedom and a shorter lever arm and so having a better design both in terms of strength and accuracy. Accordingly, placement of a pipe stand may be more accurate and faster than the use of the racker arms of the prior art. Thus whilst the guide assembly in one embodiment may provide an intermediate step, the speed by which pipe stand can be placed accurately as compared to the use of racker arms provides a distinct advantage over the prior art. 
     As mentioned whilst the invention is broad enough to include one setback assembly, the arrangement shown in  FIGS. 1A to 1C  show two setback assemblies working in parallel. One use of the dual setback assemblies may be to allow the first setback assembly to reach capacity which, subject to weight constraints, may be completely full or partially full. Once at capacity, the guide assembly or racker arms may deliver pipe stands to the second setback assembly until that reaches the capacity or the drill string has been completely withdrawn and the pipe stands stored. 
       FIGS. 4A to 4D  show a further embodiment of the present invention with a different type of racker assembly  110 . In fact the embodiment shown in  FIGS. 4A to 4D  is similar to that shown in  FIGS. 1A to 1C  whereby two setback assemblies are provided. However together with a first set of racker arms  125 ,  130  as provided with the earlier embodiment, there is also provided a second set of racker arms  135 ,  140 . Further two sets of guide assemblies  145 ,  155 ,  150 ,  160  are provided with each corresponding to one of the pairs of racker arms. The embodiment shown in  FIGS. 4A to 4D  is intended to show an arrangement that can accommodate two well centers within the same racking assembly  110 . In this embodiment, the first guide assembly  145 ,  155  works with the first pair of racker arms  125 ,  130  to service the first well center. It follows that the second guide assembly  150 ,  160  works with the second pair of racker arms  135 ,  140  to service the second well center. This arrangement may therefore have the first well center service by the first setback assembly  111  and the second well center service by the second setback assembly  112 . Alternatively, subject to logistics and control systems the first setback assembly  111  may receive pipe stands from both well centers until it has reached capacity and then the second setback assembly  112  will receive pipe stands from both well centers until each drawstring has been extracted and stored. Which particular process to adopt will depend on the circumstances and is not a limitation of the present invention. 
     In a further aspect of the present invention, a further device which acts to increase the speed of placement of pipe stand both safely and accurately is shown in  FIGS. 5A to 5F . 
       FIG. 5A  shows a slot  197  in the finger board  196  into which several pipes  191  have been slid. A first support assembly, in this case a rotatable guide  195  is in the process of delivering a pipe  190  to the slot  197 , having rotated about bearing  175 . The first support assembly acts to support the upper. As will be explained in more detail, the pipe has previously been received through a gap  180  having been delivered by a set of racker arms (not shown). 
     With regard to the process of insertion into the setback assembly,  FIG. 5C  shows a cut away view of the base to display the delivery system  200  in more detail. Here a different embodiment of the guide assembly  177  delivers several pipe stands  210  on top of a block  205 . Rather than placing the pipe stands directly in the slot, placement on the block allows several pipe stands to be placed, so that they can be delivered to the racking assembly an array. Thus the block acts both as a “buffer” for collecting pipe stands as well as a means to deliver into the racking assembly and so may accommodate a greater number of pipe stands within a given time without causing a bottleneck for the guide assembly which in itself acts to free the racker arms as quickly as possible. Thus a further advantage of the guide assembly and delivery system individually, and in combination, is to avoid bottlenecks in “upstream” systems. 
     Thus the delivery system includes the block  205  which in this embodiment is placed upon a series of vertically oriented actuators (such as hydraulic rams)  220 . The extension of the actuators  220  allows the block to move up and down relative to the base which is important in the means of delivery of the pipe stand. The block and actuators are located upon a trolley  230  which includes rollers  235 . When the block has reached its capacity (either by weight of length) of pipe stands the delivery system moves into slots  215  within the base so as to bring the pipe stands into a closely packed arrangement on the base directed radially from the center. In a further embodiment, the block will be of sufficient size to contain a sufficient number of pipe stands to completely fill each radial line of storage of the base which of course must correspond to slots within the corresponding fingerboard. 
     Once the block has reached the inner position as shown in  FIG. 5C , the actuators  220  retract as shown in  FIG. 5E . As the slot  215  in the base is sized to allow the block to project from and retract within the base, as the actuators  220  retracts and the block also retracts leaving the pipes, which are too large to pass through the slots, placed on the support face  245  of the base. The delivery system can then move the block in a retracted position using the trolley back to its original position for receiving further pipe stands. 
     In one embodiment the block may retract through the base so as to allow free rotation of the base without inference from the block. Alternatively, the trolley may permit the block to move completely out of the base so again may permit the base to rotate without interfering with the block. 
     In an alternative embodiment, the actuators may be replaced by upstands which are rotatable about a hinge. On rotation of the upstands, the block retracts beneath the support face, in a similar manner to the retraction of the actuators. 
       FIG. 5F  shows partially completed storage of the pipe stand  252  which the first base  250  and second  255  both receiving pipe stand.