Abstract:
A fingerboard latch assembly includes a latch configured for operational engagement with a fingerboard for lockingly retaining at least one tubular to the fingerboard. The latch is movable within a range of motion extending from at least a locked position to an unlocked position. A positioner operatively engaged with the latch is communicably couplable to a process control network (PCN), and is sized and shaped for receipt within a latch channel of the fingerboard. The positioner is configured to move the latch within the range of motion in response to signals received from the PCN, to capture position data for the latch, including the position of the latch at a plurality of points within the range of motion, and to communicate the captured position data to the PCN.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/515,369, entitled Offshore Drilling Rig Fingerboard Latch Position Indication, filed on Aug. 5, 2011, the contents of which are incorporated herein by reference in their entirety for all purposes. 
    
    
     BACKGROUND 
     1. Technical Field 
     This invention relates to drilling rig fingerboards, and more particularly to a fingerboard latch assembly for providing real time latch position feedback via a process control network. 
     2. Background Information 
     Oil and gas well drilling systems include numerous types of piping, referred to generally as “tubulars”. Tubulars include drill pipes, casings, and other threadably connectable oil and gas well structures. Long “strings” of joined tubulars, or drill strings, are typically used to drill a wellbore and to prevent collapse of the wellbore after drilling. The drill strings are typically stored in a structure commonly referred to as a fingerboard. Fingerboards typically include an elongated support structure(s) or “fingerboard row(s)” each capable of receiving a plurality of drill strings. Each drill string is typically individually secured to one of the finger rows by a corresponding latch, which is movable between a locked and an unlocked position. On offshore drilling rigs, these tubulars are typically stacked upright in the fingerboards, while the latches hold the tubular in place until needed. 
     In some fingerboards, the latches are manually moved between the locked and unlocked positions by an oil or gas well worker who walks across the fingerboards to manually move the latches to the desired locked or unlocked position. Due to the extreme height of the fingerboards, (in some instances 90 feet tall or more) the manual operation of the latches by the worker is undesirably dangerous. This practice may be particularly dangerous when the worker moves the latches between the locked and unlocked position by kicking the latches into or out of the locked position as the worker walks across the fingerboards, which is not an uncommon practice. 
     In an effort to make fingerboards less dangerous some manufacturers include automated latches that are pneumatically actuated. Although these latches may decrease the danger to the worker relative to the aforementioned manual approaches, they are not without drawbacks. For example, when the drilling rig operator needs to collect and use one tubular he will press a button on a control panel that will raise its latch to its unlocked position to release the tubular. However, conventional pneumatic latch controls typically do not provide feedback to the operator of the actual latch position. In some cases the latch will not raise fully and at its height on the derrick, it is generally difficult to confirm the actual position of the latch. In such a situation, a worker generally needs to climb up the derrick and walk out onto the fingerboard to determine the position of the latch. As mentioned above, the height of the fingerboard tends to make this a dangerous procedure. Moreover, in some cases the drilling rig operator will press the button again, without first determining the latch position, sending another signal in an effort to open it. This may cause the second latch behind the first to open, releasing its pipe string which may then collide with the unreleased drill pipe. This collision may damage the fingerboard making it inoperable. Since oil rigs are generally 8-10 miles off shore, service/repair of the fingerboard may be difficult and/or time consuming. Also, as a result of the collision, the pipes may be released to crash onto the rig platform below possibly harming people and causing damage. 
     It is also noted that by virtue of their function, any equipment used in connection with the fingerboards is prone to damage due to the relatively harsh conditions associated with the mud and salt water, such as may be carried by the tubulars as they are withdrawn from a well and placed back into the fingerboards for storage and re-use. 
     Thus, a need exists for a fingerboard latch actuation system that addresses drawbacks associated with the prior art. 
     SUMMARY 
     In one aspect of the present invention, a fingerboard latch assembly includes a latch configured for operational engagement with a fingerboard for lockingly retaining at least one tubular to the fingerboard. The latch is movable within a range of motion extending from a locked position to an unlocked position. A positioner operatively engaged with the latch is communicably couplable to a process control network (PCN). The positioner is configured to move the latch within the range of motion in response to signals received from the PCN, and to capture position data for the latch substantially in real time. The position data includes the position of the latch at substantially any point within the range of motion. The positioner is also configured to transmit the captured position data to the PCN, substantially in real time. 
     In another aspect of the invention, a fingerboard latch assembly includes a latch configured for operational engagement with a fingerboard for lockingly retaining at least one tubular to the fingerboard. The latch is movable within a range of motion extending from at least a locked position to an unlocked position. A positioner operatively engaged with the latch is communicably couplable to a process control network (PCN), and is sized and shaped for receipt within a latch channel of the fingerboard. The positioner is configured to move the latch within the range of motion in response to signals received from the PCN, and to capture position data for the latch, including the position of the latch at a plurality of points within the range of motion. The positioner is also configured to communicate the captured position data to the PCN. 
     In yet another aspect of the invention, a method of operating a fingerboard includes placing at least a portion of the fingerboard latch assembly of the preceding aspect of the invention within a latch channel of the fingerboard. This method further includes receiving a signal via a process control network (PCN), at the fingerboard latch assembly, and moving the latch in response to the signal, within its range of motion. The latch assembly captures position data for the latch at a plurality of points within the range of motion, and transmits the captured position data via the PCN. 
     The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: 
         FIG. 1A  is a perspective view of fingerboards on an Offshore Drilling Rig; 
         FIG. 1B  is a top view of an array of fingerboard(s) of  FIG. 1A ; 
         FIG. 2  is an enlarged view of a portion of the array of fingerboard(s) of  FIG. 1B ; 
         FIG. 3  is a perspective view, with portions shown in phantom to designate movement, of a latch usable with embodiments of the present invention; 
         FIG. 4  is a perspective view of a pneumatic cylinder usable with various embodiments of the present invention. 
         FIG. 5  is a perspective view of a portion of a fingerboard including latch channels within which embodiments of the present invention may be installed; and 
         FIGS. 6A-6D  are perspective views of various alternate latches usable with embodiments of the present invention; 
         FIG. 7  is an elevational assembly drawing of an embodiment of a latch assembly of the present invention; 
         FIG. 8  is a perspective view of a plurality of examples, networked to one another, of an alternate embodiment of the present invention, with portions removed for clarity; 
         FIG. 9A  is a front elevational view of a portion of the view of  FIG. 8 ; and 
         FIG. 9B  is a side elevational view of the embodiment of  FIG. 9A . 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized. It is also to be understood that structural, procedural and system changes may be made without departing from the spirit and scope of the present invention. In addition, well-known structures, circuits and techniques have not been shown in detail in order not to obscure the understanding of this description. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents. 
     General Overview 
     Embodiments of the present invention control and transmit the position of automated latches on fingerboards. This is accomplished by the use of positioners mounted to latches on the fingerboard assemblies. These positioners control movement and provide feedback of a pneumatic control valve, pneumatic cylinder, and/or pneumatic piston. Operators may provide a signal/communication through a control or host system to the positioner to open and/or close the latch. In response to this control signal, the positioner will open and/or close the latch while also providing a feedback signal (e.g., electrical, pneumatic, fieldbus, resistance and/or wireless, etc.) back to the control or host system indicating the specific position of the latch, e.g., open, closed, or positions therebetween. 
     In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details. 
     Terminology 
     As used herein, the terms “fieldbus” and/or “process control network” refer to a digital, two-way, multi-drop communication link among intelligent measurement and control devices, and serves as a local area network (LAN) for advanced process control, remote input/output and high speed factory automation applications. The term ‘real time’ refers to sensing and responding to external events nearly simultaneously (e.g., within milliseconds or microseconds) with their occurrence, or sufficiently fast to enable the device to keep up with an external process (for example, sufficiently fast as to avoid losing data generated by the FDs). 
     Referring now to the Figures, embodiments of the present invention will be more thoroughly described. These embodiments are directed to fingerboards  10  ( FIG. 1A ) for storing a plurality of threaded tubulars  14  ( FIG. 1B ). Each fingerboard  10  has a plurality of latches  18  for securing the threaded tubulars to the fingerboard. Each latch may include a pneumatic cylinder  22  ( FIG. 3 ) that is pneumatically actuatable to move a latch finger between a locked (closed) position and an unlocked (open) position. In the closed position, the latch secures a corresponding threaded tubular to the fingerboard. When the latch is moved to its open position, a corresponding threaded tubular may be removed from the fingerboard. 
     As best shown in  FIGS. 1A ,  1 B, and  2 , fingerboards  10  according to one embodiment of the present invention, include a plurality of elongated support structures  12  (hereinafter fingerboard rows  12 ) each capable of receiving a plurality of threaded tubulars  14 . Each fingerboard row  12  includes adjacent structures (fingers)  16 , laterally spaced apart to receive the plurality of threaded tubulars  14  therein. In the depicted embodiment, each fingerboard row  12  receives fourteen threaded tubulars  14 . However, in other embodiments each fingerboard row  12  may receive any appropriate number of threaded tubulars  14 . Note that the numbers one through fourteen on the threaded tubulars shown in the leftmost fingerboard row  12  of  FIG. 1B  and the numbers one through twelve on the uppermost threaded tubular in each fingerboard row  12  are merely shown for reference purposes. 
     As mentioned above, each fingerboard row  12  includes a plurality of corresponding latches  18 . Latches  18  may be substantially any fingerboard latch known to those skilled in the art, as may be modified in accordance with the teachings of the present invention. In the depicted embodiment, each latch  18  secures a corresponding threaded tubular  14  within its corresponding fingerboard row  12 . However, in other embodiments each latch  18  may be used to secure more than one threaded tubular  14  to the fingerboard row  12 . 
     Turning now to  FIG. 3 , each latch  18  includes an arm  20 , which is pivotably mounted to a yoke  23 , for movement between its locked/closed position as shown (as also shown in  FIGS. 1B and 2 ) and its unlocked/open position as shown in phantom at  20 ′. In the locked position, the latch  18  engages its corresponding threaded tubular  14  ( FIG. 2 ) to secure the threaded tubular  14  within a fingerboard row  12 . In the unlocked position, the latch  18  disengages its corresponding threaded tubular  14  to allow the threaded tubular  14  to be removed from its fingerboard row  12 . In the unlocked position, the latch  18  also allows for the insertion of the threaded tubular  14  into its corresponding fingerboard row  12 , where it may then be secured by moving the latch  18  from the unlocked position to the locked position. 
     As shown, latch  18  may be moved between the locked and unlocked positions by a pneumatic cylinder  22  configured to mechanically actuate (pivot) the latch arm  20  between the locked and unlocked positions. For example, as best shown in  FIG. 4 , in the particular embodiments shown and described herein, a piston  24  of cylinder  22  is extended when in the unlocked position, and retracted when in the locked position as shown at  24 ′. The end of piston  24  may thus be pivotably coupled to the arm  20  in any convenient manner, such as with a mechanical linkage  25  as shown in FIGS.  3  and  6 A- 6 D, to effect the described locking and unlocking. 
     Each latch  18  may be mounted to its corresponding fingerboard row  12  using substantially any desired mechanical fastening means, such as riveting, threaded fasteners (as shown), welding, press fit, or any combination thereof. In the depicted embodiment, each latch  18  may be secured to its corresponding fingerboard row  12  by inserting a portion thereof into an opening (latch channel)  40  ( FIG. 5 ) in the fingerboard row  12 . In the embodiment shown, yoke  23  is sized and shaped for receipt within the similarly sized and shaped latch channel  40 , e.g., up to flange portion  29  thereof. Each latch  18  may thus be inserted into latch channel  40  until the flange  29  engages an upper surface of the fingerboard  12 . Once this full insertion is reached, each latch  18  may be secured to the fingerboard row  12  by one or more of the aforementioned mechanical fastening means, such as threaded fasteners  27  passing through flange  29  as shown. 
     It should be recognized that the latches of substantially any configuration may be used in various embodiments of the present invention. Non-limiting examples of various latches that may be modified as taught herein for use in embodiments of the present invention are shown at  118 ,  218 ,  318  and  418  in  FIGS. 6A-6D . These latches may all include pneumatic cylinders as shown and described hereinabove, though substantially any other actuation devices known to those skilled in the art, including electrically and/or hydraulically operated devices, may be used without departing from the scope of the present invention. As shown, the latches of  FIGS. 6A-6D  are substantially similar to one another but for the use of latch arms  120 ,  220 ,  320 , and  420 , of various sizes and shapes as may be desired for various applications. 
     Turning now to  FIG. 7 , an embodiment of the present invention includes a latch assembly  26  having a latch  18 , as discussed hereinabove, which is equipped with a positioner  30 , such as the SRD991 pneumatic positioner available from Invensys Systems, Inc. (Foxboro, Mass.). As shown, the positioner  30  is fastened, via an L-bracket  32 , onto the latch  18 , e.g., with a clamp  34  extending circumferentially about the pneumatic cylinder  22 . As also shown, the piston  24  at one end of cylinder  22  is pivotably coupled to mechanical linkage  25 , while the other end  31  of the cylinder is secured to ground  33 . 
     Turning now to  FIGS. 8-9B , an alternate embodiment of the present invention, shown as latch assembly  26 ′, includes a modified positioner  30 ′. A plurality of assemblies  26 ′ are shown linked to one another in series, e.g., as in a typical installation within a fingerboard  10  ( FIGS. 1A-2 ). The pivot arms  20  ( FIG. 3 ) have been omitted from these figures for clarity. In this embodiment, positioner  30 ′ may include the aforementioned SRD991, as modified to fit into a box at the (e.g., bottom) end  31  of the cylinder latch opposite the yoke  23 , to provide a relatively compact assembly sized and shaped to fit within the latch channel  40  ( FIG. 5 ) of a conventional fingerboard  10 , as discussed hereinabove. This mounting configuration effectively houses the positioner  30 ′ within the fingerboard  10  to help protect the positioner  30 ′ from the relatively harsh environmental conditions associated with oil rig operation, as mentioned hereinabove. Positioner  30 ′ is substantially similar to positioner  30  shown and described hereinabove, though it may be modified to exclude the onboard display/user interface common to commercial versions of the SRD991. Instead, one or more ports (not shown) may be provided to enable users to plug a portable display/user interface into the assembly  26 ′, e.g., for initial setup and/or diagnostics. Alternatively, setup and diagnostics may be accomplished remotely, e.g., via a process control network (PCN) connection  42  as discussed below. 
     As also shown, PCN and pneumatic supply lines  42  and  44 , which in particular embodiments are routed within the fingerboards  10 , are connected to the positioners  30 ′. A pneumatic line  46  pneumatically connects each positioner  30 ′ to its respective cylinder  22 . Thus, in the embodiment shown, lines  42 ,  44  and  46  are all configured for being disposed within the fingerboards  10 , to help protect them from the harsh environmental conditions. 
     In the various embodiments shown and described herein, the positioner  30 ,  30 ′ is configured to provide feedback to the user to indicate not only when each latch  18 ,  118 , etc., is disposed in its locked and unlocked positions, but to also indicate the position of the latch at a plurality of points within its range of motion between the locked and unlocked positions. This feedback may be provided using one or more position sensors  50  ( FIG. 4 ). In particular embodiments, sensor(s)  50  may include one or more limit switches used to confirm particular discrete positions of the latch, e.g., at either end (locked and unlocked positions) and/or midrange positions within its range of motion. Sensor(s)  50  may also include one or more potentiometers, such as may be disposed internally to the cylinder  22 , to provide a signal corresponding to substantially any position with the range of motion of the latch. In particular embodiments, the potentiometer(s) may be a conventional resistive (analog) device, configured to generate a signal which may be converted by the positioner into a digital signal suitable for transmission via the PCN line  42 . Moreover, a combination of potentiometer and limit switches may be used, e.g., with the limit switch(es) used to calibrate the potentiometer(s). It should be recognized that substantially any type of sensor(s) known to those skilled in the art may be used in these embodiments, without departing from the scope of the present invention. However, particular embodiments use sensors configured to directly engage moveable portions of the latch. Such direct engagement may be effected in either a contact or non-contact manner, e.g., using conventional limit switches, and/or using non-contact devices such as conventional inductive, capacitive, magnetic, and photoelectric sensors, and the like. Moreover, in particular embodiments, the sensor(s)  50  is disposed for being housed within the latch channel along with the positioner  30 ′ and a portion of the latch  18 ,  118 , etc., such as by placing sensor  50  internally to the cylinder  22  as described hereinabove. 
     It should be noted that the positioners  30 ,  30 ′ may be configured to communicate via network connection  42  using substantially any communication protocol known to those skilled in the art of industrial automation. Examples of protocols that may be used include Profibus, ModBus, FOUNDATION fieldbus, HART, Ethernet, and conventional 4-20 ma analog signal, etc., and combinations thereof. Moreover, both wired and wireless protocols may be used, as well as non-electrical (e.g., pneumatic) signaling approaches. In this regard, although network connection  42  is shown as a hard-wired electrical connection, substantially any type of connection known to those skilled in the art, including wireless or non-electrical (e.g., pneumatic) connections may be used without departing from the scope of the present invention. In particular embodiments, the positioners  30 ,  30 ′ may be configured to transmit latch position data via PCN  42  substantially in real time, e.g., to provide substantially real time position information to the PCN operator. The positioners  30 ,  30 ′ may push this information to the network  42 , and/or may provide this real time information in response to requests sent via the PCN. 
     Having described exemplary embodiments of latch assemblies of the present invention, an exemplary method in accordance with the present invention will be described with reference to the following Table I. As shown therein, at  70 , at least a portion of a fingerboard latch assembly  26 ,  26 ′, etc., is received within a latch channel of a fingerboard. At  72 , the fingerboard latch assembly receives a signal via the PCN. At  74 , the latch is moved in response to the signal, and position data for the latch is captured  76  at a plurality of points within its range of motion. At  78 , the latch assembly transmits the captured data via the PCN. 
     Optional aspects of this method are shown at  80 - 86  of Table II, and include  80  capturing position data at substantially any point within the range of motion;  82  capturing position data using a potentiometer;  84  disposing the positioner within the latch channel; and  86 , effecting the capturing  76  and transmitting  78  substantially in real time. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE I 
               
               
                   
                   
               
             
             
               
                   
                 70 
                 Fingerboard latch assembly disposed within a latch channel; 
               
               
                   
                 72 
                 Signal received at fingerboard latch assembly; 
               
               
                   
                 74 
                 Latch moved in response to signal, within range of motion; 
               
               
                   
                 76 
                 Latch position data captured at a plurality of points within 
               
               
                   
                   
                 the range of motion; 
               
               
                   
                 78 
                 Position data transmitted via PCN. 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
               
               
             
           
               
                   
                 TABLE II 
               
               
                   
                   
               
             
             
               
                   
                 80 
                 capture position data at substantially any point within the 
               
               
                   
                   
                 range of motion 
               
               
                   
                 82 
                 capture position data using a potentiometer 
               
               
                   
                 84 
                 dispose the positioner within latch channel 
               
               
                   
                 86 
                 capturing 76 and transmitting 78 substantially in real time 
               
               
                   
                   
               
             
          
         
       
     
     In the preceding specification, the invention has been described with reference to specific exemplary embodiments for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. 
     It should be further understood that any of the features described with respect to one of the embodiments described herein may be similarly applied to any of the other embodiments described herein without departing from the scope of the present invention.