Wellhead product testing system

Abstract

A method of controlling flows from plural hydrocarbon extraction wellhead trees ( 50, 52, 54, 56 ) in an extraction system including plural wellhead trees ( 50 ) connected by a pipeline network ( 60, 62, 88, 104 ) to a host facility ( 64 ) via a manifold system ( 130, 132 ) situated remotely from the host facility ( 64 ). Each wellhead tree ( 50 ) has a production outlet connected by a production conduit ( 88 ) to the manifold system ( 130, 132 ) and a test flow outlet ( 76 ) connected by a test conduit ( 104 ) to the manifold system ( 130, 132 ). Wellhead tree outlet valves are operable to divert the flow from one wellhead tree only to the manifold system ( 130, 132 ) from where it is routed via a test pipeline ( 62 ) to testing equipment at the host facility. Alternatively, one or more modules ( 132 ) of the manifold system ( 130, 132 ) may be replaced by one or more different modules each containing a multi-phase flow meter so that testing can take place at the manifold system. The method obviates the requirement for remotely operable valves to be installed in the manifold system for flow testing purposes.

1 . A method of controlling flows from plural hydrocarbon extraction wellhead trees ( 50 ,  52 ,  54 ,  56 ) in an extraction system including plural wellhead trees ( 50  . . . ) connected by a pipeline network ( 60 ,  62 ,  88 ,  104 ) to a host facility ( 64 ) via a manifold system ( 58 ) situated remotely from the host facility ( 64 ), the method involving selective opening and closing of valves ( 74 ,  78 ) controlling the flows through the pipeline network to enable selective delivery of output from a selected wellhead tree ( 50  . . . ) to testing means for analysing the content of the output from the selected wellhead tree wherein the method includes the steps of providing each wellhead tree ( 50  . . . ) with a production flow outlet ( 72 ), a test flow outlet ( 76 ) and valve means ( 74 ,  78 ) operable to selectively divert the output from the wellhead tree ( 50  . . . ) through one of the outlets ( 72 ,  76 ) and operating the valve means ( 74 ,  78 ) to divert the output of one wellhead tree only to the testing means.  
     
     
         2 . The method of according to  claim 1  including the step of providing each wellhead tree ( 50  . . . ) with a production flow valve ( 74 ) and a test flow valve ( 78 ) for respectively controlling output through the production and test flow outlets ( 72 ,  76 ) which valves ( 74 ,  78 ) constitute the valve means of the wellhead tree ( 50  . . . ).  
     
     
         3 . The method according to  claim 1  or  2  including the step of connecting the test flow outlets ( 76 ) of two or more wellhead trees ( 50  . . . ) with each other by a test conduit ( 104 ) to form a wellhead tree group and connecting the test conduit ( 104 ) to the manifold system ( 58 ).  
     
     
         4 . The method of  claim 3  wherein two or more wellhead trees ( 50  . . . ) of the group are connected in parallel to the test conduit ( 104 ).  
     
     
         5 . The method of claims  2  and  3  including the step of opening the test flow valve ( 78 ) of a selected one of the wellhead trees ( 50  . . . ) of the group only while maintaining the or each other test flow valve ( 78 ) closed and passing output from the selected wellhead tree ( 50  . . . ) to the testing means via the test conduit ( 104 ).  
     
     
         6 . The method of  claim 5  wherein output from the selected wellhead tree ( 52 ,  54 ,  56 ) passes through a portion of the test conduit ( 104 ) connecting two wellhead trees ( 50 ,  52 ,  54 ,  56 ) prior to passing through a different part of the test conduit ( 104 ) for delivery to the manifold system ( 58 ).  
     
     
         7 . The method according to any preceding claim including the step of connecting the test flow outlet ( 76 ) of each wellhead tree ( 212 ) to the manifold system ( 130 ) by an individual test conduit ( 210 ).  
     
     
         8 . The method according to claims  2  and  7  including the step of opening the test flow valve ( 76 ) of a selected one of the wellhead trees ( 212 ) only while maintaining the others closed and passing output from the selected wellhead tree ( 212 ) to the testing means via the corresponding individual test conduit ( 210 ).  
     
     
         9 . The method according to any preceding claim wherein the manifold system comprises a docking manifold ( 130 ) for receiving one or more system modules ( 132 ,  158 ,  180 ) for acting on wellhead tree outputs flowing through the manifold system and the method includes docking at least one such system module ( 132 ,  158 ,  180 ) in the docking manifold ( 130 ).  
     
     
         10 . The method according to  claim 9  wherein at least one said system module ( 132 ) docked in the docking manifold ( 130 ) simply provides through connection firstly ( 150 ) between the production flow outlets ( 72 ) of the wellhead trees ( 50  . . . ) and a production pipeline ( 60 ) connecting the docking manifold ( 130 ) and the host facility ( 64 ) and secondly ( 152 ) between the test flow outlets ( 76 ) of the wellhead trees ( 50  . . . ) and a test pipeline ( 62 ) connecting the docking manifold ( 130 ) and the testing means which is situated at the host facility ( 64 ), the method including the step of conveying output from a selected one of the wellhead trees ( 50  . . . ) to the testing means via the system module ( 132 ).  
     
     
         11 . The method according to  claim 9  wherein at least one said system module ( 158 ) docked in the docking manifold ( 130 ) firstly ( 164 ,  160 ) provides simple throughflow connection between the production flow outlets ( 72 ) of the wellhead trees ( 50  . . . ) and a production pipeline ( 60 ) connecting the docking manifold ( 130 ) and the host facility ( 64 ) and secondly ( 168 ,  160 ) includes the testing means ( 162 ), the method including the step of conveying output from a selected one of the wellhead trees ( 50  . . . ) to the testing means ( 162 ) of the system module ( 158 ) and analysing its contents.  
     
     
         12 . The method according to  claim 9  wherein at least one said system module ( 180 ) docked in the docking manifold ( 130 ) includes the testing means ( 202 ) and separating means ( 194 ) for separating constituent components of the flows from the wellhead trees ( 50  . . . ), the method including the step of operating the valve means ( 74 ,  78 ) of the wellhead trees ( 50  . . . ) to divert the output from one selected wellhead tree test flow outlet ( 76 ) only to the separating means ( 194 ) and measuring and/or analysing its contents with the testing means ( 202 ).  
     
     
         13 . The method according to any preceding claim wherein control signals for controlling the valve means ( 74 ,  78 ) of each wellhead tree ( 50  . . . ) are provided from the host facility ( 64 ).  
     
     
         14 . The method according to  claim 13  wherein the control signals are routed to the wellhead trees ( 50  . . . ) via the manifold system ( 58 ) but without passing through any control means forming part of the manifold system ( 58 ).  
     
     
         15 . The method according to  claim 13  wherein the control signals are routed to the wellhead trees ( 50  . . . ) without passing through the manifold system.  
     
     
         16 . The method according to  claim 9  wherein at least one of the system modules ( 158 ,  180 ) includes the testing means ( 162 ,  202 ), the method including the step of conveying output from a selected one of the wellhead trees ( 50  . . . ) to the testing means ( 162 ,  194 ) of the system module ( 158 ,  202 ).  
     
     
         17 . A method of operating a hydrocarbon extraction system including the methods of claims  10  and  12  including the steps of employing the method of  claim 10  involving conveying output from a selected one of the wellhead trees ( 50  . . . ) to the testing means via the system module ( 132 ) and the test pipeline ( 62 ) and subsequently employing the method of  claim 12  and conveying one of the constitute components from the separating means ( 194 ) to the host facility ( 64 ) via the pipeline ( 190 ) previously used as the test pipeline ( 62 ).  
     
     
         18 . Apparatus for controlling flows from plural hydrocarbon extraction wellhead trees ( 50  . . . ) in an extraction system including plural wellhead trees ( 50  . . . ) connected by a pipeline network ( 60 ,  62 ,  88 ,  104 ) to a host facility ( 64 ) via a manifold ( 58 ) situated remotely from the host facility ( 64 ) characterised by each wellhead tree ( 50  . . . ) having a production flow outlet ( 72 ), a test flow outlet ( 76 ) and valve means ( 74 ,  78 ) operable to selectively divert output from the wellhead tree ( 50  . . . ) through one of the outlets ( 72 ,  76 ) and the interconnecting pipeline network for delivering the output from one of the test flow outlets ( 76 ) to the testing means.