Abstract:
The method of providing a shuttle valve which will accept 3 or more inputs, comprising providing a body having a bore and an outlet, providing two or more shuttles within the bore, providing an inlet in the body between each of the shuttles, and causing flow from an inlet to move the shuttles to positions appropriate to allow flow from the inlet into the shuttle valve and blocking flow out of the other of the inlets.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to the method of shuttling fluid from more than 2 input ports to a single outlet for the control of functions, especially in deep water. 
       CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0002]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0003]    Not applicable 
       REFERENCE TO A “MICROFICHE APPENDIX” 
       [0004]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0005]    Subsea drilling control systems as used on subsea blowout preventer stacks have conventionally had two redundant control systems—a blue system and a yellow system. The systems are completely redundant down to the point of a shuttle valve which accepts flow from either of the control systems and delivers it to the function to be controlled. The shuttle valve becomes a single point of failure of the system as when it fails, the system is completely disabled. 
         [0006]    There has been some limited additional control by either an acoustically controlled system or a hydraulic connection called a “hot stab” from a remotely operated vehicle or an ROV. If either of these devices are used, a second shuttle valve must be introduced into the system with an additional fail point. 
         [0007]    With the new safety requirements, there will be a trend to having both an acoustically controlled backup system and an ROV controlled backup system. This leads to tripling in the number of required shuttle valves as well as a considerable complication to the plumbing, which is already complex. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The object of this invention is to provide a single shuttle valve which can receive more than 2 inputs. 
         [0009]    A second object of this invention is to provide a shuttle valve which can have as many inputs as desired. 
         [0010]    A third objective of the present invention is to simplify the plumbing required to deal with multiple input signals to a single outlet. 
         [0011]    Another objective of this present invention is to provide rotational flexibility on installation but rigid after installation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a view of a deepwater drilling system which would use the shuttle valve of this invention. 
           [0013]      FIG. 2  is a graphical representation of the blowout preventer of  FIG. 1  showing the blue control pod, the yellow control pod, and the typical shuttle valve arrangement for receiving control from 2 locations. 
           [0014]      FIG. 3  is the graphical representation of  FIG. 2  showing the complication of the plumbing when additional inputs from 2 other sources is desired. 
           [0015]      FIG. 4  is the graphical representation of  FIG. 2  showing the shuttle valve of the present invention illustrating how many fewer connections are required. 
           [0016]      FIG. 5  is a cross section of the shuttle valve of the present invention showing fluid being input into or received out of a port. 
           [0017]      FIG. 6  is a cross section of the shuttle valve of the present invention showing fluid being input into or received out of a different port. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Referring now to  FIG. 1 , a view of a complete system for drilling subsea wells  20  is shown in order to illustrate the utility of the present invention. The drilling riser  22  is shown with a central pipe  24 , outside fluid lines  26 , and control lines  28 . 
         [0019]    Below the drilling riser  22  is a flex joint  30 , lower marine riser package  32 , lower blowout preventer stack  34  and wellhead  36  landed on the seafloor  38 . 
         [0020]    Below the wellhead  36 , it can be seen that a hole was drilled for a first casing string, that string  40  was landed and cemented in place, a hole drilled through the first string for a second string, the second string  42  cemented in place, and a hole is being drilled for a third casing string by drill string  44  which includes drill bit  45 , heavy weight drill collars  46 , and lighter weight drill pipe  47 . 
         [0021]    The lower Blowout Preventer stack  34  generally comprises a lower hydraulic connector for connecting to the subsea wellhead system  36 , usually 4 or 5 ram style Blowout Preventers, an annular preventer, and an upper mandrel for connection by the connector on the lower marine riser package  32 . 
         [0022]    Below outside fluid line  26  is a choke and kill (C&amp;K) connector  50  and a pipe  52  which is generally illustrative of a choke or kill line. Pipe  52  goes down to valves  54  and  56  which provide flow to or from the central bore of the blowout preventer stack as may be appropriate from time to time. Typically a kill line will enter the bore of the Blowout Preventers below the lowest ram and has the general function of pumping heavy fluid to the well to overburden the pressure in the bore or to “kill” the pressure. The general implication of this is that the heavier mud will not be circulated, but rather forced into the formations. A choke line will typically enter the well bore above the lowest ram and is generally intended to allow circulation to circulate heavier mud into the well to regain pressure control of the well. 
         [0023]    Normal drilling circulation is the mud pumps  60  taking drilling mud  62  from tank  64 . The drilling mud will be pumped up a standpipe  66  and down the upper end  68  of the drill pipe  47 . It will be pumped down the drill pipe  47 , out the drill bit  45 , and return up the annular area  70  between the outside of the drill pipe  47  and the bore of the hole being drilled, up the bore of the casing  42 , through the subsea wellhead system  36 , the lower blowout preventer stack  34 , the lower marine riser package  32 , up the drilling riser  24 , out a bell nipple  72  and back into the mud tank  64 . 
         [0024]    During situations in which an abnormally high pressure from the formation has entered the well bore, the thin walled central pipe  24  is typically not able to withstand the pressures involved. Rather than making the wall thickness of the relatively large bore drilling riser thick enough to withstand the pressure, the flow is diverted to a choke line  26 . It is more economic to have a relatively thick wall in a small pipe to withstand the higher pressures than to have the proportionately thick wall in the larger riser pipe. 
         [0025]    When higher pressures are to be contained, one of the annular or ram Blowout Preventers are closed around the drill pipe and the flow coming up the annular area around the drill pipe is diverted out through choke valve  54  into the pipe  52 . The flow passes up through C&amp;K connector  50 , up pipe  26  which is attached to the outer diameter of the riser  24 , through choking means illustrated at  74 , and back into the mud tanks  64 . 
         [0026]    On the opposite side of the drilling riser  24  is shown a cable or hose  28  coming across a sheave  80  from a reel  82  on the vessel  84 . The cable  28  is shown characteristically entering the top of the lower marine riser package  32 . These cables typically carry hydraulic, electrical, multiplex electrical, or fiber optic signals. Typically there are at least two of these systems, which are characteristically painted yellow and blue. As the cables or hoses  28  enter the top of the lower marine riser package  32 , they typically enter the top of the control pod to deliver their supply or signals. When hydraulic supply is delivered, a series of accumulators are located on the lower marine riser package  32  or the lower Blowout Preventer stack  34  to store hydraulic fluid under pressure until needed. 
         [0027]    Referring now to  FIG. 2 , blowout preventer  100  has rams  102  and  104  which will sealingly engage each other to seal the bore. Pistons  106  and  108  are pressurized through line  110  to move them towards the bore to move the rams  102  and  104  into the bore  112 . Line  110  is pressurized through line  116  from blue control pod  118  or through line  120  from yellow control pod  122 . As this occurs flow from the opposite side of pistons  106  and  108  flows through line  130  to shuttle valve  132  and back to either the blue pod  118  through line  134  or the yellow pod  122  through line  136 . This can be repeated for up to one hundred functions on a complex subsea drilling system. 
         [0028]    Referring now to  FIG. 3 , shuttle valve  114  is complimented with shuttle valves  140  and  142  in order to receive signals through line  144  from an acoustic control pod or through line  146  from an ROV. Likewise shuttle valve  132  is complimented with shuttle valves  150  and  152  in order to receive signals through line  154  from an acoustic control pod or through line  156  from an ROV. As one can imagine, if this is repeated for  100  different functions, the control systems become extremely complex. 
         [0029]    Referring now to  FIG. 4 , the triple shuttle valves of  FIG. 3  are replaced by a single shuttle of the type of this invention. The same line designations are used to illustrate how much simpler the plumbing becomes with the use of this valve. Multi-port shuttle valve  160  has replaced shuttle valves  114 ,  140 , and  142  along with all the associated plumbing. Multi-port shuttle valve  162  has replaced shuttle valves  132 ,  150 , and  152  along with all the associated plumbing. 
         [0030]    Referring now to  FIG. 5 , multi-port shuttle valve  160  is shown in detail. Body  200  has inlet/outlet ports  202 ,  204 ,  206 , and  208 . Pivot axle  210  has a thread  212  and seal  214  on one end to engage a function to be operated such as a blowout preventer. When the head  216  is turned to screw the pivot axle  210  into the desired function, the body  200  is free to be swiveled until the spacer  218  contacts the face of the object to be engaged and the spring washers  220  are preloaded. This preloading will friction lock the body  200  into a specific desired orientation so the unit will not swivel in service. End plug  230  has seals  232  which sealingly engage bore  234  of body  200  at the first end. End plug  240  has seals  244  which sealingly engage bore  242  at the second end. 
         [0031]    Shuttles  250 ,  252 , and  254  have seals  260 ,  262 , and  264  respectively to seal in bore  242  of body  200  and have internal seals  270 ,  272 , and  274  which seal against projections  280 ,  282 , and  284  respectively. End plug  230  has projection  286  and end plug  240  has internal seal  288 . 
         [0032]    Double arrows  290 ,  292 ,  294 , and  296  illustrate the flow path from the control system attached to port  204  to the operated function to which pivot axle  210  is attached. 
         [0033]    Referring now to  FIG. 6 , multi-port shuttle  160  has had flow input from the function attached to port  208  and shuttles  252  and  254  have been moved (upwards on the page) to allow the flow path as indicated by the double arrows  300 ,  302 ,  304 , and  306 . Similarly flow into ports  202 ,  204 , or  206  will shift shuttles to appropriate positions to direct the flow appropriately. 
         [0034]    The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.