External Oil Expansion Chamber for Seabed Boosting ESP Equipment

• US 20100329893A1
• Filed: 06/28/2010
• Published: 12/30/2010
• Est. Priority Date: 06/29/2009
• Status: Active Grant

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Martinez, Ignacio, Merrill, Dan A.
• Granted Patent: US 8,485,797 B2
• Time in Patent Office: Days
• US Class Current: 417/53
• CPC Class Codes: E21B 43/128 Adaptation of pump systems with down-hole electric drives
• CPC Class Codes: E21B 47/017 Protecting measuring instruments
• CPC Class Codes: F04D 13/08 for submerged use
• CPC Class Codes: F04D 13/10 adapted for use in mining bore holes
• CPC Class Codes: F04D 29/086 especially adapted for liquid pumps

Abstract

An expansion chamber to serve ESP equipment installed on the seabed located in either a caisson or a conduit on a skid. The expansion chamber provides an external reservoir for expansion and contraction of motor oil in the ESP equipment. During operation of an ESP, the heat generated in the motor raises the temperature of the motor oil, causing it to expand. The expansion chamber is connected to the ESP equipment via oil lines that allow oil to expand into the expansion chamber when the temperature of the motor oil increases. The expansion chamber has a movable barrier therein that defines primary and secondary chamber. Oil communicates with the primary chamber. Formation fluid within the conduit surrounding the motor communicates with the secondary chamber.

Claims

1. A method for boosting pressure of well fluid flowing from a subsea well, comprising:

mounting a motor and a pump within a subsea conduit;

providing a submerged expansion housing external of the conduit in a vicinity of a sea floor, the expansion housing having a movable barrier therein, defining a primary and a secondary fluid chamber;

flowing formation fluid into the conduit around the motor and operating the motor and pump to pump formation fluid from the capsule;

communicating a dielectric lubricant from the motor with the primary chamber within the expansion chamber;

communicating formation fluid with the secondary chamber within the expansion chamber; and

allowing the flexible barrier to move to equalize pressure between the primary and secondary chambers.

2. The method of claim 1, wherein the movable barrier comprises a bellow and communicating the dielectric lubricant comprises flowing the dielectric lubricant to move into an interior of flexible bellows.

3. The method of claim 2, wherein communicating formation fluid comprises flowing the formation fluid around an exterior of the bellows.

4. The method of claim 2, wherein primary and secondary chambers are sealed from hydrostatic pressure of seawater.

5. The method of claim 1, wherein the conduit comprises a capsule located on a sea floor.

6. The method of claim 1, further comprising providing a second submerged expansion housing having a movable barrier, therein;

communicating a dielectric lubricant comprising flowing dielectric lubricant to the primary chamber of the first mentioned expansion housing;

communicating formation fluid comprising flowing formation fluid to secondary chamber of secondary expansion chamber; and

communicating dielectric lubricant from the secondary chamber of the first expansion housing to the primary chamber of the secondary expansion housing.

7. The method of claim 1, wherein the conduit comprises a caisson extending into the sea floor and the expansion housing is located on the sea floor.

8. The method of claim 1, wherein a battery of mechanical seals is located between the motor and the pump and an expansion chamber is located at a base of the motor.

9. A subsea electrical submersible booster pumping system, comprising:

a conduit;

a centrifugal pump within the conduit, and having an inlet for drawing fluid from the conduit into the pump and an outlet to discharge fluid from the conduit, and located within the conduit;

an electrical motor cooperatively coupled to the centrifugal pump;

an expansion housing exterior of the conduit, the expansion housing having a movable barrier therein, defining a primary and a secondary chamber;

a dielectric lubricant line in communication with an interior of the motor and connected to the primary chamber of the thermal expansion housing; and

a formation fluid line in communication with the interior of the conduit exterior of the motor and connected to the secondary chamber of the expansion chamber.

10. The system of claim 9, wherein the movable barrier expansion housing substantially equalizes pressure between the primary and secondary chambers.

11. The system of claim 10, wherein the movable barrier comprises a bellows that can expand and contract as the dielectric lubricant expands and contracts.

12. The system of claim 10, wherein the expansion housing is sealed so as to prevent hydrostatic pressure of sea water from acting on the primary and secondary chambers.

13. The system of claim 10, wherein the conduit comprises a capsule located on the sea floor.

14. The system of claim 9, wherein a battery of mechanical seals is located between the motor and the pump and an expansion chamber is located at a base of the motor.

15. The method of claim 9, further comprising providing a second submerged expansion housing having a movable barrier, therein;

communicating a dielectric lubricant comprising flowing dielectric lubricant to the primary chamber of the first mentioned expansion housing;

communicating formation fluid comprising flowing formation fluid to secondary chamber of secondary expansion chamber; and

communicating dielectric lubricant from the secondary chamber of the first expansion housing to the primary chamber of the secondary expansion housing.

16. The system of claim 9, wherein a plurality of the expansion housing are connected in series, a coupling line connecting a primary chamber of one expansion housing to a secondary chamber of a second expansion housing, the secondary chamber defined by the inner surface of the second expansion housing and the external surface of a primary chamber within the second expansion chamber.

17. The system of claim 9, wherein the secondary chamber of the one of the expansion housing and the primary chamber of the second expansion housing are pre-filled with dielectric lubricant.

18. The system of claim 9, wherein the dielectric lubricant line and the formation fluid line connected to the expansion housing pass through a cap located at one end of the conduit.

19. The system of claim 9, wherein the expansion housing is located exterior to a caisson that contains the motor and the centrifugal pump within, the caisson extending into the seabed.

20. A subsea booster pump system, comprising:

a subsea conduit having a well fluid inlet and a well fluid outlet;

a centrifugal pump and electric motor located in the conduit;

an expansion housing located subsea exterior of the conduit;

an inlet dielectric fluid line connected between the motor and the expansion housing;

an inlet well fluid line connected between the conduit and the expansion housing; and

the expansion chamber having a movable barrier between the inlet dielectric fluid line and the inlet well fluid line.