System and method for injecting water into an underwater hydrocarbon reservoir

Abstract

Water is supplied from a host facility ( 2 ) to a pump ( 10 ) in a seabed facility ( 5 ) via a connecting pipeline ( 6 ). The pump ( 10 ) pumps the water to a higher pressure, and injects the pumped water into a hydrocarbon reservoir at a pressure higher than the pressure of the fluid in the reservoir so that it drives production fluid there to the host facility ( 2 ).

1 . A system ( 1 ) for injecting water into a hydrocarbon reservoir, comprising a host facility ( 2 ) having water supply means ( 3 ), an underwater pump ( 10 ) remote from the host facility ( 2 ), and connected to the water supply means ( 3 ) by a pipeline ( 6 ), and at least one water injection well ( 7 ) connected to the underwater pump ( 10 ) whereby the pump ( 10 ) is arranged to pump the water received from the pipeline ( 6 ) to the or each well ( 7 ) to inject the pumped water into the reservoir at a pressure higher than the pressure of the fluid in the reservoir, characterised in that 
 said underwater pump comprises an electric motor driven pump ( 10 ).    
     
     
         2 . A system as claimed in  claim 1 , wherein the pump ( 10 ) is connected to the at least one water injection well ( 7 ) by at least one flowline ( 8 ) which is able to withstand conveyed fluid of a higher pressure than the pipeline ( 6 ) between the host facility ( 2 ) and the underwater pump ( 10 ).  
     
     
         3 . A system as claimed in  claim 1  or  2 , wherein the pump ( 10 ) is located at an underwater facility ( 5 ).  
     
     
         4 . A system as claimed in  claim 3 , wherein the underwater facility ( 5 ) includes a retrievable module ( 16 ) which incorporates the pump ( 10 ).  
     
     
         5 . A system as claimed in any preceding  claim 1 , including a power and control umbilical ( 13 ) from the host facility ( 2 ) to the underwater pump ( 10 ) for conveying power and control signals to the pump.  
     
     
         6 . A system as claimed in  claim 5 , wherein the power and control umbilical ( 13 ) is arranged to convey power and control signals required for other underwater equipment.  
     
     
         7 . A method for injecting water into a hydrocarbon reservoir, comprising the steps of supplying water from a host facility ( 2 ) to an underwater pump ( 10 ) via a connecting pipeline ( 6 ), pumping the water received by the underwater pump ( 10 ) to a higher pressure, and injecting the pumped water into the reservoir at a pressure higher than the pressure of the fluid in the reservoir, characterised by the step of: 
 driving the underwater pump ( 10 ) with an electric motor.