Pressure driven pumping system

1. A pressure driven pumping system, comprising:

a housing;

a separating member disposed within a first bore of the housing to separate a process chamber from a working chamber, the separating member movable within the housing; and

a rod member coupled to the separating member and extending into a reduced pressure chamber, the reduced pressure chamber being sealed from the working chamber and configured for sustaining a pressure less than a pressure in the working chamber;

one or more working fluid ports passing through the housing to the working chamber; and

one or more working fluid valves for controlling flow through the one or more working fluid ports,

wherein the separating member comprises a first face exposed to a process fluid and a second face exposed to a working fluid, the first face having an effective area greater than an area of the second face,

wherein the working chamber is sandwiched between the process chamber and the reduced pressure chamber such that the rod member extends through the entire working chamber; and

wherein at least one of the working fluid ports is in fluid communication with a pump for passing working fluid into the working chamber.

2. The pressure driven pumping system of claim 1 , wherein the first face of the separating member further comprises a piston member in sealing engagement with the first bore of the housing.

3. The pressure driven pumping system of claim 2 , wherein the piston comprises a first face exposed to the process chamber and a second face exposed to the working chamber, the second face having an effective area equal to between 25% and 75% of an effective area of the first face.

4. The pressure driven pumping system of claim 1 , wherein at least one of the working fluid ports is in fluid communication with seawater when the housing is submerged in the seawater.

5. The pressure driven pumping system of claim 1 , further comprising one or more process fluid ports passing through the housing to the process chamber, wherein at least one of the process fluid ports is adapted for fluid communication with a subsea wellhead.

6. The pressure driven pumping system of claim 5 , wherein at least one of the process fluid ports is adapted for fluid communication with a production line.

7. The pressure driven pumping system of claim 1 , further comprising a flow control device in communication with the working chamber for controlling flow of working fluid out of the working chamber.

8. The pressure driven pumping system of claim 1 , further comprising:

a diaphragm disposed within the housing for preventing migration of fluid from the process chamber to the working chamber.

9. The pressure driven pumping system of claim 8 , wherein the diaphragm comprises a rolling diaphragm disposed within the process chamber.

10. A pumping system to be connected to a subsea well for extracting a well fluid from the well, the pumping system comprising:

a housing having a process chamber, a working chamber and a reduced pressure chamber in this order;

a separating member disposed within a first bore of the housing to separate the process chamber from the working chamber, the separating member being movable within the housing;

a rod member coupled to the separating member and extending through the working chamber into the reduced pressure chamber, the reduced pressure chamber being sealed from the working chamber and configured to sustain a pressure less than a pressure in the working chamber,

wherein the process chamber has a first port configured to be connected to the well and a second port configured to be connected to a pipe that takes the well fluid to a surface of sea,

wherein the working chamber has a first port configured to be connected to ambient seawater and a second port configured to be connected to an external pump,

wherein the pressure reduced chamber has a single port, and

a ratio of an area of a face of the separating member to an area of a face of the rod member are set such that a pressure of the well fluid, when smaller than a pressure of the ambient seawater, pushes out the seawater from the working chamber and the well fluid into the process chamber.

11. A pressure driven pumping system, comprising:

a housing;

a separating member disposed within a first bore of the housing to separate a process chamber from a working chamber, the separating member movable within the housing;

a rod member coupled to the separating member and extending into a reduced pressure chamber, the reduced pressure chamber being sealed from the working chamber and configured for sustaining a pressure less than a pressure in the working chamber; and

one or more process fluid ports passing through the housing to the process chamber, wherein at least one of the process fluid ports is adapted for fluid communication with a subsea wellhead,

wherein the separating member comprises a first face exposed to a process fluid and a second face exposed to a working fluid, the first face having an effective area greater than an area of the second face, and

wherein the working chamber is sandwiched between the process chamber and the reduced pressure chamber such that the rod member extends through the entire working chamber.

12. The pressure driven pumping system of claim 11 , wherein the first face of the separating member further comprises a piston member in sealing engagement with the first bore of the housing.

13. The pressure driven pumping system of claim 12 , wherein the piston comprises a first face exposed to the process chamber and a second face exposed to the working chamber, the second face having an effective area equal to between 25% and 75% of an effective area of the first face.

14. The pressure driven pumping system of claim 11 , further comprising:

one or more working fluid ports passing through the housing to the working chamber;

one or more working fluid valves for controlling flow through the one or more working fluid ports; and

wherein at least one of the working fluid ports is in fluid communication with a pump for passing working fluid into the working chamber.

15. The pressure driven pumping system of claim 14 , wherein at least one of the working fluid ports is in fluid communication with seawater when the housing is submerged in the seawater.

16. The pressure driven pumping system of claim 11 , wherein at least one of the process fluid ports is adapted for fluid communication with a production line.

17. The pressure driven pumping system of claim 11 , further comprising a flow control device in communication with the working chamber for controlling flow of working fluid out of the working chamber.

18. The pressure driven pumping system of claim 11 , further comprising:

a diaphragm disposed within the housing for preventing migration of fluid from the process chamber to the working chamber.

19. The pressure driven pumping system of claim 18 , wherein the diaphragm comprises a rolling diaphragm disposed within the process chamber.

20. A pressure driven pumping system, comprising:

a housing;

a separating member disposed within a first bore of the housing to separate a process chamber from a working chamber, the separating member movable within the housing;

a rod member coupled to the separating member and extending into a reduced pressure chamber, the reduced pressure chamber being sealed from the working chamber and configured for sustaining a pressure less than a pressure in the working chamber; and

a diaphragm disposed within the housing for preventing migration of fluid from the process chamber to the working chamber,

wherein the separating member comprises a first face exposed to a process fluid and a second face exposed to a working fluid, the first face having an effective area greater than an area of the second face, and

wherein the working chamber is sandwiched between the process chamber and the reduced pressure chamber such that the rod member extends through the entire working chamber.

21. The pressure driven pumping system of claim 20 , wherein the first face of the separating member further comprises a piston member in sealing engagement with the first bore of the housing.

22. The pressure driven pumping system of claim 21 , wherein the piston comprises a first face exposed to the process chamber and a second face exposed to the working chamber, the second face having an effective area equal to between 25% and 75% of an effective area of the first face.

23. The pressure driven pumping system of claim 20 , further comprising:

one or more working fluid ports passing through the housing to the working chamber;

one or more working fluid valves for controlling flow through the one or more working fluid ports; and

wherein at least one of the working fluid ports is in fluid communication with a pump for passing working fluid into the working chamber.

24. The pressure driven pumping system of claim 23 , wherein at least one of the working fluid ports is in fluid communication with seawater when the housing is submerged in the seawater.

25. The pressure driven pumping system of claim 20 , further comprising one or more process fluid ports passing through the housing to the process chamber, wherein at least one of the process fluid ports is adapted for fluid communication with a subsea wellhead.

26. The pressure driven pumping system of claim 25 , wherein at least one of the process fluid ports is adapted for fluid communication with a production line.

27. The pressure driven pumping system of claim 20 , further comprising a flow control device in communication with the working chamber for controlling flow of working fluid out of the working chamber.

28. The pressure driven pumping system of claim 20 , wherein the diaphragm comprises a rolling diaphragm disposed within the process chamber.