Subsea hydrocarbon production system

Abstract

A system ( 1 ) for extracting subsea hydrocarbon fluid has five discrete subsea developments ( 10, 12, 14, 16, 18 ) for hydrocarbon extraction linked to four hydrocarbon receiving facilities ( 2, 4, 6, 8 ) by a pipeline network ( 94 ). Each subsea development ( 10, 12, 14, 16, 18 ) has a manifold to which pipelines of the network ( 94 ) are connected, and a pair of retrievable modules ( 22 ) docked on the manifold. Each module has a control pod which is able to control flows of fluids between the subsea developments and between the subsea developments and the receiving facilities, and each control pod is connected to monitoring devices for monitoring parameters pertaining to the subsea developments. Parameters are monitored at a first one of the subsea developments and a requirement for a first fluid type is identified and parameters at another second one of the subsea developments are monitored and a surplus of the first fluid type is identified. The relevant control pods are then operated to enable a quantity of the first fluid to be conveyed from the second to the first subsea development via the pipeline network ( 94 ).

1 . A system for extracting subsea hydrocarbon fluid comprising at least three discrete subsea developments for hydrocarbon extraction and a hydrocarbon receiving facility linked by a pipeline network configured to permit: 
 (a) diversion of fluid from at least one of said subsea developments selectively to one or more of said other developments; and    (b) conveyance of fluid from each of said subsea developments to said receiving facility.    
   
   
       2 . The system as claimed in  claim 1 , wherein said pipeline network is also configured to permit conveyance of fluid from at least one of said subsea developments to said receiving facility selectively via at least two alternative routes.  
   
   
       3 . The system as claimed in  claim 1  comprising a plurality of receiving facilities, wherein said pipeline network is configured to permit conveyance of fluid from each of said subsea developments to any said receiving facility.  
   
   
       4 . The system as claimed in  claim 1 , wherein said pipeline network further comprises plural pipelines between at least two of said subsea developments, said pipelines being suitable for respectively conveying different fluids such as hydrocarbon liquid, hydrocarbon gas and water.  
   
   
       5 . The system as claimed in  claim 3 , comprising a control means for controlling flows of fluids between said subsea developments and between said subsea developments and at least one said receiving facility.  
   
   
       6 . The system as claimed in  claim 5 , wherein said control means comprises a monitoring means for monitoring parameters pertaining to at least one of said subsea developments.  
   
   
       7 . The system as claimed in  claim 5 , wherein said control means comprises signal processing means located at said subsea developments, wherein said subsea developments communicate thereby and control, at least to a limited extent, the distribution of fluids around said pipeline network.  
   
   
       8 . The system as claimed in  claim 5 , wherein the said control means is arranged to operate by automatically sensing what items of hardware are in use at a particular subsea development.  
   
   
       9 . The system as claimed in  claim 8 , wherein each said item of hardware comprises an electronic chip containing identification information.  
   
   
       10 . The system as claimed in any  claim 5 , comprising a remote input/receiving device for effecting control of the flow of said fluids.  
   
   
       11 . The system as claimed in  claim 5 , wherein said control means further comprises means to calculate the best place to store or dispose of a particular fluid.  
   
   
       12 . The system as claimed in  claim 1 , wherein at least one of said subsea developments comprises separating means for at least substantially separating constituent components of fluid received by said subsea development from each other.  
   
   
       13 . The system as claimed in  claim 1 , wherein at least one of said subsea developments comprises a manifold connected to said pipeline network; and 
 at least one retrievable module having equipment for acting on fluid received thereby;    wherein said module is docked with said manifold for fluid connection to said pipeline network.    
   
   
       14 . The system as claimed in  claim 3 , comprising a network of power lines between said subsea developments and each receiving facility for distributing power.  
   
   
       15 . The system as claimed in  claim 3 , comprising a network of control lines between said subsea developments and each said receiving facility for transmitting control signals.  
   
   
       16 . The system as claimed in  claim 3 , comprising a network of chemical injection lines between said subsea developments and each said 3receiving facility for conveying chemical injection fluids.  
   
   
       17 . A method of operating a system for extracting subsea hydrocarbon fluid, the system comprising plural discrete subsea developments for hydrocarbon extraction and a hydrocarbon receiving facility linked by a pipeline network and control means for controlling flows of fluids between the subsea developments and between the subsea developments and the receiving facility, the control means comprising monitoring means for monitoring parameters pertaining to the subsea developments, the method comprising the steps of: 
 (i) monitoring parameters at a first subsea development and identifying a requirement for a first fluid type;    (ii) monitoring parameters at a second subsea development and identifying a surplus of the first fluid type; and    (iii) operating the control means to convey a quantity of the first fluid from the second to the first subsea development via the pipeline network.    
   
   
       18 . The method as claimed in  claim 17 , wherein the system comprises plural receiving facilities and at least one of the subsea developments comprises separating means for at least substantially separating constituent components of fluid received by the development from each other, the method comprising the steps of: 
 (i) at least substantially separating fluid received by the subsea developments into first and second fluid types;    (ii) conveying the first fluid type to one of the receiving facilities; and    (iii) conveying the second fluid type to another of the receiving facilities.