Abstract: A pressure driven pumping system and methods for using pressure driven pumping systems. The pressure driven pumping system may include at least one pumping element. Each pumping element includes a housing having a bore at least partially bounded by first and second outer walls. A first piston is disposed between the first outer wall and the inner wall, to define a first outer chamber and a first inner chamber. A second piston is disposed between the second outer wall and the inner wall, to define a second outer chamber and a second inner chamber. A coupling member couples the first and second pistons. A plurality of valves control flow of seawater to the first and second outer chambers, and control flow of well fluid to the first inner chamber of each pumping element. A control unit controls the plurality of valves to pump well fluid. A method for using pressure driven pumping systems includes pumping injection well fluid to an injection well in conjunction with producing from a production well.

Abstract: A pressure driven pumping system includes a piston disposed within a first bore of a housing to separate a process chamber from a working chamber. A rod member coupled to the separating member extends into a reduced pressure chamber. The piston has a first face exposed to the process chamber and a second face exposed to the working chamber. The second face has an effective area less than an effective area of the first face. The housing may be placed in seawater at a selected depth. The process chamber can be in fluid communication with a well to pass well fluid into the process chamber at well pressure to move the piston, to discharge seawater from the seawater chamber. The working fluid, typically seawater in a subsea application, is pumped into the working chamber to move the piston, which discharges well fluid from the process chamber.