Subsea manifold system

Abstract

A modular, subsea hydrocarbon production hub 36 comprises a primary manifold 22 and a plurality of co-located extension structures 26, 30, 34 . The primary manifold 22 has first connections 23 for connection a top-side facility 21 , second connections 27, 35 for connection to at least one extension structure 26, 34 , and third connections 25 for connection to at least one well 24 . The extension structures 26, 30, 34 may comprise a secondary manifold 26, 30 , having first connections 27, 31 for connection to the primary manifold 22 or another secondary manifold 26, 30 , second connections 31 for connection to at least one further extension structure 26, 30, 36 , and third connections 28, 31 for connection to further wells 29, 32 . The extension structures 26, 30, 34 may also comprise one or more functional units, such as a pumping unit 34 or a separator unit 51.

1 . A modular, subsea hydrocarbon production hub comprising a primary manifold and one or more co-located extension structure(s), the primary manifold having first connections for connection to at least a riser and an umbilical from a top-side facility, and second connections for connection to at least one extension structure, wherein at least one of the extension structure(s) comprises a secondary manifold having first connections connected to the second connections of the primary manifold, second connections for connection to at least one further extension structure, and third connections for connection to at least one wellhead or template, the secondary manifold providing for a flow of produced hydrocarbon from the at least one wellhead or template to the top-side facility via the primary manifold and the riser, and facilitating electrical and/or hydraulic control from the top-side facility via the primary manifold and the umbilical. 
     
     
         2 . A hub according to  claim 1 , wherein the second connections of the primary manifold provide services in respect of water injection and/or gas injection to the secondary manifold. 
     
     
         3 . A hub according to  claim 1 , wherein the second connections of the primary manifold provide power to the secondary manifold. 
     
     
         4 . A hub according to  claim 1 , wherein the primary manifold has third connections for connection to at least one wellhead or template. 
     
     
         5 . A hub according to  claim 1 , wherein each of the extension structures is within 500 meters, and preferably within 100 meters, of the primary manifold. 
     
     
         6 . A hub according to  claim 1 , wherein the extension structures comprise a plurality of secondary manifolds. 
     
     
         7 . A hub according to  claim 6 , wherein at least two of the secondary manifolds are connected to the primary manifold in series. 
     
     
         8 . A hub according to  claim 6 , wherein at least two of the secondary manifolds are connected to the primary manifold or to another secondary manifold in parallel. 
     
     
         9 . A hub according to  claim 1 , wherein the primary manifold comprises a valving arrangement so that flow within various production lines of the primary manifold may be controlled and/or a switching arrangement for distribution of electrical power, communications and control. 
     
     
         10 . A hub according to  claim 1 , wherein one of the extension structures comprises a service unit connected to the second connections of the primary manifold or an extension structure, wherein the service unit provides an ancillary service, and preferably provides one or more of the following: processing of produced fluids, such as separation of oil from water and/or gas, oil, gas and water treatment; boosting of fluid by means of a pump or compressor; and measuring the flow of one or more fluid streams. 
     
     
         11 . A hub according to  claim 1 , wherein one of the extension structures comprises a separator unit connected to second connections of the primary manifold or an extension structure. 
     
     
         12 . A hub according to  claim 11 , wherein the separator unit separates water from a hydrocarbon stream before the hydrocarbon stream is passed to the riser. 
     
     
         13 . A hub according to  claim 11 , wherein the separator unit separates a hydrocarbon gas phase from a hydrocarbon liquid phase, and optionally wherein the gas phase is used to provide gas lift and/or the liquid phase is used as a driving medium for an ejector. 
     
     
         14 . A hydrocarbon production system comprising a top-side production platform connected by means of a riser and an umbilical to a hub on the sea floor according to  claim 1 , the hub being in turn connected subsea to one or more wells, wherein hydrocarbons produced from each of the wells flow to the platform via a secondary manifold of the hub, the primary manifold of the hub, and the riser, and wherein one or more of service fluids, electrical control signals, electrical power and injection fluids are transmitted to each of the wells via first the primary manifold and then a secondary manifold. 
     
     
         15 . A method of connecting a subsea wellhead to a top-side production platform via a modular, subsea hydrocarbon production hub connected to the platform via a riser and an umbilical, the method comprising:
 connecting a secondary manifold to the subsea hub; and   connecting the wellhead subsea to the extension manifold of the hub such that hydrocarbons produced from the wellhead flow to the platform via the hub and the riser, and one or more of service fluids, electrical control signals, electrical power and injection fluids are transmitted to the wellhead via the hub and the umbilical.