Frontier Field Development System for Large Riser Count and High Pressures for Harsh Environments

Abstract

A system comprising a semisubmersible, at least two offloading terminals and shuttle tankers in optional combination with an FSO may be deployed in deep water harsh environments where riser performance (either SCR or LWSCR) is a key performance parameter. The semisubmersible is used to support the risers because of its favorable motion characteristics under harsh conditions. The semisubmersible supports the entire process train and provides well maintenance, which may include water and/or gas injection. The semisubmersible may provide work-over capabilities for well intervention. The produced hydrocarbons are exported through flexible pipes to at least two off-loading buoys. A FSO or shuttle tanker receives the produced hydrocarbons. Two or more off-loading buoys may be employed to allow for uninterrupted production when a shuttle-tanker-only embodiment is utilized.

What is claimed is: 
     
         1 . A system for offshore oilfield development comprising:
 a semi-submersible having hydrocarbon processing equipment thereon;   a plurality of subsea risers in fluid communication with the hydrocarbon processing equipment and wellheads on the seafloor;   a submersible mooring buoy having means for fluid connection to a shuttle tanker moored to the mooring buoy; and   at least one fluid conduit connecting the mooring buoy to the hydrocarbon processing equipment on the semi-submersible.