SYSTEMS AND METHODS OF USING SUBSEA FRAMES AS A HEAT EXCHANGER IN SUBSEA BOOSTING SYSTEMS

• US 20110247788A1
• Filed: 06/17/2011
• Published: 10/13/2011
• Est. Priority Date: 06/29/2009
• Status: Active Grant

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Mack, John J., Brown, Donn J., Tetzlaff, Steven K., Martinez, Ignacio, Merrill, Dan A.
• Granted Patent: US 8,708,675 B2
• Time in Patent Office: Days
• US Class Current: 165/104.33
• CPC Class Codes: F04D 13/10 adapted for use in mining bore holes
• CPC Class Codes: F04D 29/061 especially adapted for liquid pumps
• CPC Class Codes: F04D 29/588 cooling or heating the machine F04D29/5886, F04D29/5893 take precedence

Abstract

Systems and methods of cooling a motor of an electrical submersible pump (ESP) assembly employed in an electrical submersible subsea booster pumping system, are provided. A supporting frame structure such as an ESP mounting skid or top end assembly of a caisson having structural members exposed to environmental seawater, is modified or designed to include fluid conduits within the structural members to establish lubricant pathways for lubricant to flow. A heated/hot lubricant line connects between a supporting structure lubricant inlet port and an ESP motor lubricant outlet port. A cooled lubricant line connects between a supporting structure lubricant outlet port and an ESP motor lubricant inlet port. A pump or other fluid moving device circulates lubricant from the ESP motor to the lubricant pathways within the supporting frame structure, whereby the seawater cools the lubricant contained therein, which is then circulated back into the motor to assisting cooling the motor.

Claims

1. A method of cooling a motor of an electrical submersible pump assembly employed in an electrical submersible subsea booster pumping system, the method comprising the steps of:

circulating dielectric lubricant from a dielectric lubricant outlet port of a motor housing of a subsea electrical submersible pump motor to an inlet port of at least one of a plurality of elongate main structural members of a subsea supporting frame structure;

circulating the dielectric lubricant through the plurality of elongate main structural members, each of the plurality of elongate main structural members having a fluid conduit formed at least partially therethrough along a longitudinal axis thereof and in fluid communication with the fluid conduit of at least one other of the plurality of elongate main structural members;

removing heat from the dielectric lubricant circulating through the plurality of elongate main structural members by transferring heat energy in the dielectric lubricant to seawater flowing through the subsea supporting frame structure and across outer surfaces of the plurality of elongate main structural members to thereby reduce the temperature of the dielectric lubricant; and

circulating the dielectric lubricant from an outlet port of at least one of the plurality of elongate main structural members of the subsea supporting frame structure to a dielectric lubricant inlet port of the motor housing.

2. A method as defined in claim 1,

wherein the subsea supporting frame structure comprises an electrical submersible pump mounting skid positioned in a vicinity of a sea floor;

wherein the method further comprises the step of positioning at least major portions of an electrical submersible pump assembly within the confines of the mounting skid, the at least major portions of the subsea electrical pump assembly including the subsea electrical submersible pump motor; and

wherein the step of circulating the dielectric lubricant through the plurality of elongate main structural members includes the step of circulating the dielectric lubricant through corresponding main structural members of the electrical submersible pump mounting skid.

3. A method as defined in claim 2, wherein the subsea electrical submersible pump motor is positioned within a containment vessel also having a dielectric lubricant outlet port and a dielectric lubricant inlet port, wherein the electrical submersible pump assembly further includes a first conduit segment, a second conduit segment, a third conduit segment, a fourth conduit segment, and a fluid moving device, and wherein the method further comprises the steps of:

connecting the first conduit segment between the dielectric lubricant outlet port in the housing of the motor and the dielectric lubricant outlet port in the containment vessel to circulate the dielectric lubricant therethrough;

connecting the second conduit segment between the dielectric lubricant outlet port in the containment vessel and the inlet port of at least one of plurality of elongate main structural members of the electrical submersible pump mounting skid;

connecting the third conduit segment between the dielectric lubricant inlet port in the containment vessel and the dielectric lubricant inlet port in the housing of the motor to circulate the dielectric lubricant therethrough;

connecting the fourth conduit segment between the outlet port of at least one of plurality of elongate main structural members and the dielectric lubricant inlet port in the containment vessel; and

positioning the fluid moving device within the housing of the motor to provide motivation to circulate the dielectric lubricant.

4. A method as defined in claim 2, further comprising the step of:

connecting the plurality of elongate main structural members of the electrical submersible pump mounting skid to form a plurality of interconnected fluid pathways through the elongate main structural members of the electrical submersible pump mounting skid; and

wherein the step of circulating the dielectric lubricant through the plurality of elongate main structural members includes circulating respective portions of the dielectric lubricant through each separate one of the plurality of fluid pathways within the electrical submersible pump mounting skid.

5. A method as defined in claim 2, wherein a total quantity of the dielectric lubricant circulated within the plurality of tubes of the electrical submersible pump mounting skid and dielectric lubricant circulation components within confines of the motor housing exceed a dielectric lubricant capacity of the dielectric lubricant circulation components within the confines of the motor housing by at least a factor of three to thereby enhance cooling of the motor.

6. A method as defined in claim 1,

wherein the subsea supporting frame structure comprises a top end assembly of a subsea caisson positioned in a vicinity of a sea floor;

wherein the method further comprises the step of positioning at least major portions of the electrical submersible pump assembly within the confines of the subsea caisson, the at least major portions of the subsea electrical pump assembly including the subsea electrical submersible pump motor; and

wherein the step of circulating the dielectric lubricant through the plurality of elongate main structural members of a subsea supporting frame structure includes the step of circulating the dielectric lubricant through main structural members of the top end assembly of the subsea caisson.

7. A method as defined in claim 6, wherein the subsea electrical submersible pump motor is housed within a containment vessel also having a dielectric lubricant outlet port and a dielectric lubricant inlet port, wherein the electrical submersible pump assembly further includes a first conduit segment, a second conduit segment, a third conduit segment, a fourth conduit segment, and a fluid moving device, and wherein the method further comprises the steps of:

connecting the first conduit segment between the dielectric lubricant outlet port in the housing of the motor and the dielectric lubricant outlet port in the containment vessel to circulate the dielectric lubricant therethrough;

connecting the second conduit segment between the dielectric lubricant outlet port in the containment vessel and the inlet port of at least one of plurality of elongate main structural members of the top end assembly of the subsea caisson;

connecting a third conduit segment between the outlet port of at least one of plurality of elongate main structural members and the dielectric lubricant inlet port in the containment vessel;

connecting the fourth conduit segment between the dielectric lubricant inlet port in the containment vessel and the dielectric lubricant inlet port in the housing of the motor to circulate the dielectric lubricant therethrough; and

positioning the fluid moving device within the housing of the motor to provide motivation to circulate the dielectric lubricant.

8. A method as defined in claim 6, further comprising the step of:

connecting the plurality of elongate main structural members of the top end assembly of the subsea caisson to form a plurality of interconnected fluid pathways through the elongate main structural members of the top end assembly of the subsea caisson; and

wherein the step of circulating the dielectric lubricant through the plurality of elongate main structural members includes circulating respective portions of the dielectric lubricant through each separate one of the plurality of fluid pathways within the top end assembly of the subsea caisson.

9. A method as defined in claim 6, wherein a total quantity of the dielectric lubricant circulated within the plurality of elongate main structural members of the top end assembly of the subsea caisson and dielectric lubricant circulation components within confines of the motor housing exceed a dielectric lubricant capacity of the dielectric lubricant circulation components within the confines of the motor housing by at least a factor of three to thereby enhance cooling of the motor.

10. A method of cooling a motor of an electrical submersible pump employed in an electrical submersible subsea booster pumping system, the method comprising the steps of:

providing a electrical submersible pump assembly in a vicinity of a sea floor, the electrical submersible pump assembly including a motor and at least one pump housed within a containment vessel, the motor including a housing having a dielectric lubricant inlet port and a dielectric lubricant outlet port, the containment vessel also having a dielectric lubricant inlet port and a dielectric lubricant outlet port, the electrical submersible pump assembly further including a first conduit segment extending between the dielectric lubricant outlet port in the housing of the motor and the dielectric lubricant outlet port in the containment vessel and a second conduit segment extending between the dielectric lubricant inlet port in the containment vessel and the dielectric lubricant inlet port in the housing of the motor;

providing a subsea supporting frame structure adjacent the electrical submersible pump assembly, the subsea supporting frame structure comprising one of the following;

a mounting skid framing at least major portions of the electrical submersible pump assembly, and a top end assembly of a subsea caisson, the subsea supporting frame structure comprising a plurality of elongate main structural members, each of the plurality of elongate main structural members having a fluid conduit extending along a longitudinal axis thereof and interconnected so that the fluid conduits collectively form a manifold structure, at least one of the plurality of elongate main structural members including a fluid inlet port in fluid communication with the dielectric lubricant outlet port in the containment vessel of the electrical submersible pump assembly defining a supporting frame structure fluid inlet, at least one of the plurality of elongate main structural members including a fluid outlet port in fluid communication with the dielectric lubricant inlet port in the containment vessel of the electrical submersible pump assembly defining a supporting frame structure fluid outlet, portions of the dielectric lubricant flowing along a plurality of different pathways between the fluid inlet and the fluid outlet of the supporting frame structure formed by the plurality of elongate main structural members;

circulating dielectric lubricant from the dielectric lubricant outlet port of the motor housing to the fluid inlet of the supporting frame structure;

removing heat from the dielectric lubricant circulating through the plurality of elongate main structural members flowing through the plurality of different pathways between the fluid inlet and the fluid outlet of the supporting frame structure, by transferring heat energy in the dielectric lubricant to seawater flowing through the subsea supporting frame structure and across outer surfaces of the plurality of elongate main structural members to thereby reduce the temperature of the dielectric lubricant; and

circulating the dielectric lubricant from the outlet port of the supporting frame structure to the dielectric lubricant inlet port of the motor housing.

11. A system for cooling a motor of an electrical submersible pump assembly employed in an electrical submersible subsea booster pumping system, the system comprising:

an electrical submersible pump assembly including a subsea electrical submersible pump having a motor, a motor housing, a dielectric lubricant outlet port extending through a first portion of the housing, and a dielectric lubricant inlet port extending through a second portion of the housing, the dielectric lubricant outlet port spaced apart from the dielectric lubricant inlet port;

a subsea supporting frame structure having a plurality of elongate main structural members, each of the plurality of elongate main structural members having an exterior surface substantially exposed to seawater when positioned in a subsea environment and having a main body having a fluid conduit formed at least partially therethrough along a longitudinal axis thereof, the plurality of fluid conduits and corresponding plurality of elongate main structural members connected to form a plurality of different dielectric lubricant pathways between a supporting frame structure fluid inlet and a supporting frame structure fluid outlet;

at least one fluid conduit extending between the motor housing dielectric lubricant outlet port and the supporting frame structure fluid inlet to thereby form a heated dielectric lubricant discharge pathway therebetween;

at least one fluid conduit extending between the supporting frame structure fluid outlet and the motor housing dielectric lubricant inlet port to thereby form a cooled dielectric lubricant return pathway therebetween; and

a fluid moving device positioned to circulate dielectric lubricant for the motor through the heated dielectric lubricant discharge pathway, the plurality of different dielectric lubricant pathways through the supporting frame structure to be cooled by seawater when deployed therein, and the cooled dielectric lubricant return pathway.

12. A system as defined in claim 11,

wherein the subsea supporting frame structure comprises an electrical submersible pump mounting skid positioned in a vicinity of a sea floor;

and

wherein at least major portions of the electrical submersible pump assembly are positioned within the confines of the mounting skid, the at least major portions of the subsea electrical pump assembly including the subsea electrical submersible pump motor.

13. A system as defined in claim 12,

wherein at least one of the plurality of elongate main structural members includes a fluid inlet port defining the supporting frame structure fluid inlet;

wherein at least one of the plurality of elongate main structural members includes a fluid outlet port defining the supporting frame structure fluid outlet; and

wherein the plurality of different dielectric lubricant pathways are configured to collectively form a manifold structure to facilitate a transfer of heat energy in dielectric lubricant circulating through the plurality of different dielectric lubricant pathways to seawater flowing through the subsea supporting frame structure and across outer surfaces of the plurality of elongate main structural members when the supporting frame structure and electrical submersible pump assembly are operationally deployed to thereby reduce temperature of the dielectric lubricant.

14. A system as defined in claim 12, further comprising:

a containment vessel having a dielectric lubricant outlet port and a dielectric lubricant inlet port, and positioned to contain at least major portions of the electrical submersible pump assembly;

wherein the at least one fluid conduit extending between the motor housing dielectric lubricant outlet port and the supporting frame structure fluid inlet includes a first conduit segment connected between the motor housing dielectric lubricant outlet port and the containment vessel dielectric lubricant outlet port and a second conduit segment connected between the containment vessel dielectric lubricant outlet port and the supporting frame structure fluid inlet; and

wherein the at least one fluid conduit extending between the supporting frame structure fluid outlet and the motor housing dielectric lubricant inlet port includes a third conduit segment connected between the supporting frame structure fluid outlet and the containment vessel dielectric lubricant inlet port and a fourth conduit segment connected between the containment vessel dielectric lubricant inlet port and the motor housing dielectric lubricant inlet port.

15. A system as defined in claim 12, wherein a total quantity of the dielectric lubricant circulated within the fluid conduits in the elongate main structural members of the electrical submersible pump mounting skid and dielectric lubricant circulation components within confines of the motor housing exceed a dielectric lubricant capacity of the dielectric lubricant circulation components contained within the confines of the motor housing by at least a factor of at least four to thereby enhance cooling of the motor.

16. A system as defined in claim 11,

wherein the subsea supporting frame structure comprises a top end assembly of a subsea caisson positioned in a vicinity of a sea floor;

and

wherein at least major portions of the electrical submersible pump assembly are positioned within the confines of the subsea caisson, the at least major portions of the subsea electrical pump assembly including the subsea electrical submersible pump motor.

17. A system as defined in claim 16,

wherein at least one of the plurality of elongate main structural members includes a fluid inlet port defining the supporting frame structure fluid inlet;

wherein at least one of the plurality of elongate main structural members includes a fluid outlet port defining the supporting frame structure fluid outlet; and

wherein the plurality of different dielectric lubricant pathways are configured to collectively form a manifold structure to facilitate a transfer of heat energy in dielectric lubricant circulating through the plurality of different dielectric lubricant pathways to seawater flowing through the subsea supporting frame structure and across outer surfaces of the plurality of elongate main structural members when the supporting frame structure and electrical submersible pump assembly are operationally deployed to thereby reduce temperature of the dielectric lubricant.

18. A system as defined in claim 16, further comprising:

a containment vessel having a dielectric lubricant outlet port and a dielectric lubricant inlet port, and positioned to contain at least major portions of the electrical submersible pump assembly;

wherein the at least one fluid conduit extending between the motor housing dielectric lubricant outlet port and the supporting frame structure fluid inlet includes a first conduit segment connected between the motor housing dielectric lubricant outlet port and the containment vessel dielectric lubricant outlet port and a second conduit segment connected between the containment vessel dielectric lubricant outlet port and the supporting frame structure fluid inlet; and

wherein the at least one fluid conduit extending between the supporting frame structure fluid outlet and the motor housing dielectric lubricant inlet port includes a third conduit segment connected between the supporting frame structure fluid outlet and the containment vessel dielectric lubricant inlet port and a fourth conduit segment connected between the containment vessel dielectric lubricant inlet port and the motor housing dielectric lubricant inlet port.

19. A system as defined in claim 16, wherein a total quantity of the dielectric lubricant circulated within the fluid conduits in the elongate main structural members of the top end assembly of the subsea caisson and dielectric lubricant circulation components within confines of the motor housing exceed a dielectric lubricant capacity of the dielectric lubricant circulation components contained within the confines of the motor housing by at least a factor of at least four to thereby enhance cooling of the motor.

20. A system for cooling a motor of an electrical submersible pump assembly employed in an electrical submersible subsea booster pumping system, the system comprising:

an electrical submersible pump assembly including a subsea electrical submersible pump having a motor, a motor housing, a dielectric lubricant outlet port extending through a first portion of the housing, and a dielectric lubricant inlet port extending through a second portion of the housing, the dielectric lubricant outlet port spaced apart from the dielectric lubricant inlet port;

a containment vessel positioned to contain at least major portions of the electrical submersible pump assembly and having a dielectric lubricant outlet port and a dielectric lubricant inlet port;

a subsea supporting frame structure having a plurality of elongate main structural members, each of the plurality of elongate main structural members having an exterior surface substantially exposed to seawater when positioned in a subsea environment and having a main body having a fluid conduit formed at least partially therethrough along a longitudinal axis thereof, each fluid conduit positioned in fluid communication with at least one other of a plurality of fluid conduits corresponding to the plurality of elongate main structural members, at least one of the plurality of elongate main structural members including a fluid inlet port in fluid communication with the dielectric lubricant outlet port in the containment vessel of the electrical submersible pump assembly defining a supporting frame structure fluid inlet, at least one of the plurality of elongate main structural members including a fluid outlet port in fluid communication with the dielectric lubricant inlet port in the containment vessel of the electrical submersible pump assembly defining a supporting frame structure fluid outlet, a plurality of different dielectric lubricant pathways extending between the fluid inlet and the fluid outlet of the supporting frame structure and through a corresponding different set of one or more of the plurality of fluid conduits, the plurality of different dielectric lubricant pathways configured to facilitate a transfer of heat energy in dielectric lubricant circulating through the plurality of different dielectric lubricant pathways to seawater flowing through the subsea supporting frame structure and across outer surfaces of the plurality of elongate main structural members when the supporting frame structure and electrical submersible pump assembly are operationally deployed to thereby reduce temperature of the dielectric lubricant;

at least one fluid conduit extending between the motor housing dielectric lubricant outlet port and the supporting frame structure fluid inlet to thereby form a heated dielectric lubricant discharge pathway therebetween;

at least one fluid conduit extending between the supporting frame structure fluid outlet and the motor housing dielectric lubricant inlet port to thereby form a cooled dielectric lubricant return pathway therebetween; and

a fluid moving device positioned to circulate dielectric lubricant for the motor through the heated dielectric lubricant discharge pathway, the plurality of different dielectric lubricant pathways through the supporting frame structure to be cooled by seawater when deployed therein, and the cooled dielectric lubricant return pathway.