System and method for hydraulically powering a seafloor pump for delivering produced fluid from a subsea well

Abstract

A system and method for hydraulically powering a seafloor pump and thereby delivering produced fluid from a subsea well are provided. The system includes a power fluid source, such as a seawater source, which is located at a seasurface location of a sea, and a hydraulically-driven pump, which is located at a seafloor location. The pump is configured to receive a flow of produced fluid from a subsea well and deliver the produced fluid through a riser to a receiver at a seasurface location. One or more conduits that define a feed passage connect the source and the pump, and the source is configured to receive power fluid and provide a flow of the power fluid via the feed passage of the conduit to the pump. The pump is hydraulically operated by the flow of power fluid and delivers the produced fluid from the pump to the receiver.

1 . A system for hydraulically powering a seafloor pump for delivering produced fluid from a subsea well, the system comprising:
 a power fluid source located at a first seasurface location of a sea;   a hydraulic pump located at a seafloor location, the pump configured to receive a flow of produced fluid from a subsea well and deliver the produced fluid through a riser to a receiver at a second seasurface location; and   at least one conduit defining a feed passage connecting the source and the pump,   wherein the source is configured to receive power fluid and provide a flow of the power fluid via the feed passage of the conduit to the pump to thereby hydraulically operate the pump and deliver the produced fluid from the pump to the receiver.   
     
     
         2 . A system according to  claim 1  wherein the source is configured to receive seawater from the sea as the power fluid at the seasurface location and the pump is configured to discharge the flow of seawater to the sea at the seafloor location. 
     
     
         3 . A system according to  claim 1  wherein the at least one conduit further comprises a return passage connecting the pump to the source and wherein the source is configured to deliver the flow of power fluid to the pump via the feed passage and return the flow of power fluid to the source via the return passage. 
     
     
         4 . A system according to  claim 1  wherein the pump is configured to deliver the produced fluid and the flow of power fluid as a mixed stream to the receiver via the riser. 
     
     
         5 . A system according to  claim 4  wherein the receiver is a separator configured to separate the power fluid from the produced fluid. 
     
     
         6 . A system according to  claim 1 , further comprising a seawater treatment device at the first seasurface location, the seawater treatment device configured to receive a flow of seawater from the sea as the power fluid, process the seawater, and provide the flow of the seawater to the source as the power fluid. 
     
     
         7 . A system according to  claim 1  wherein the source is a pump configured to increase the pressure of the power fluid to thereby provide the flow of the power fluid, the pump being powered by at least one of the group consisting of electric and hydraulic power. 
     
     
         8 . A system according to  claim 1  wherein the source and the receiver are collocated on a topside structure. 
     
     
         9 . A method for hydraulically powering a seafloor pump for delivering produced fluid from a subsea well, the method comprising:
 delivering a pressurized flow of power fluid from a source at a first seasurface location of a sea via a feed passage of a conduit to a hydraulic pump located at a seafloor location;   receiving by the hydraulic pump a flow of produced fluid from a subsea well; and   hydraulically operating the pump by the flow of power fluid such that the pump delivers the produced fluid through a riser to a receiver at a second seasurface location.   
     
     
         10 . A method according to  claim 9  wherein the source receives seawater from the sea at the seasurface location as the power fluid and the pump discharges the flow of seawater to the sea at the seafloor location. 
     
     
         11 . A method according to  claim 9 , further comprising returning the flow of power fluid from the pump to the source via a return passage separately from the produced fluid. 
     
     
         12 . A method according to  claim 9 , further comprising delivering the produced fluid and the flow of power fluid as a mixed stream to the receiver via the riser. 
     
     
         13 . A method according to  claim 12 , further comprising separating the power fluid from the produced fluid in the receiver. 
     
     
         14 . A method according to  claim 9 , further comprising receiving a flow of seawater from the sea as the power fluid, processing the seawater, and providing the flow of the processed seawater to the source. 
     
     
         15 . A method according to  claim 9  wherein delivering the pressurized flow of power fluid from the source to the pump comprises operating a pump at the first seasurface location to increase the pressure of the power fluid at the first seasurface location, the pump being powered by at least one of the group consisting of electric and hydraulic power. 
     
     
         16 . A method according to  claim 9  wherein the source delivers the pressurized flow of power fluid from a topside structure and the pump delivers the produced fluid through the riser to the receiver located on the topside structure.