초록 ▼

The production rate, useful life and operating efficiency of electric submergible pumping systems (ESP) is improved by operating the system so that the motor (220, 320) is cooled by two passes of production. Production fluids remove waste heat from the motor (220, 320) by passing the fluid in contac

The production rate, useful life and operating efficiency of electric submergible pumping systems (ESP) is improved by operating the system so that the motor (220, 320) is cooled by two passes of production. Production fluids remove waste heat from the motor (220, 320) by passing the fluid in contact with the exterior of the motor (220, 320). The improved cooling permits the motor to be operated at a lower temperature improving life and efficiency, and/or to be operated at higher power at a similar temperature. Additionally, oversized and excess equipment is not required, further improving performance and economics for the user. In another aspect, the invention is a method of pumping fluids using a motor having vortex generators (366) on its exterior surfaces or on the interior surfaces of a surrounding shroud.

대표청구항 ▼

The invention claimed is: 1. A method for producing fluids from a well having a casing that contains perforations through which production fluids enter the well, comprising (a) positioning an electrical submergible pumping system including an electric motor within said casing such that the electric

The invention claimed is: 1. A method for producing fluids from a well having a casing that contains perforations through which production fluids enter the well, comprising (a) positioning an electrical submergible pumping system including an electric motor within said casing such that the electric motor is at or below at least some of said perforations, and (b) pumping production fluids from the well with said pumping system, wherein (1) the pumping system includes a pump, an electrical motor having a hollow rotor shaft and production fluid intakes located below said electrical motor, said pumping system being adapted to pump said production fluids through said hollow rotor shaft of the electrical motor, (2) production fluids entering the well through at least some of the perforations in the casing pass in fluid contact with exterior portions of the electrical motor and remove heat therefrom before entering the production fluid intakes, and (3) production fluids pass through the hollow rotor shaft of the electrical motor as the fluid travels to the wellhead, and remove additional heat from the motor. 2. The method of claim 1 wherein the production fluids pass though the hollow rotor shaft of the electrical motor under conditions of turbulent flow. 3. The method of claim 2 wherein the electrical motor is located between the wellhead and the pump. 4. The method of claim 3 wherein production fluids entering the well through the perforations in the casing travel downward in fluid contact with exterior portions of the electrical motor to an intake, and the liquid production fluids are subsequently pumped upwardly through the hollow rotor shaft of the electrical motor and then to the wellhead. 5. The method of claim 4, wherein the flow of production fluid through the hollow rotor shaft is characterized by a Reynolds number of at least 2300. 6. The method of claim 5 wherein the motor contains a motor fluid at a positive pressure to the exterior of the motor, and has seals which allow motor fluid to leak into the production fluid. 7. The method of claim 5, wherein conditions are selected such that heat transfer from at least one of the hollow rotor shaft and the exterior surfaces of the motor to the production fluid is characterized by a Nusselt number of at least 10. 8. The method of claim 5 wherein conditions are selected so as to generate a Brinkmann number of less than 2. 9. The method of claim 5 wherein conditions are selected so as to generate a Rossby number of more than 0.5. 10. The method of claim 2 wherein the pump is located between the wellhead and the electric motor. 11. The method of claim 2 wherein the electrical submergible pumping system contains two pumps, one of which is located above the electric motor and one of which is located below the electric motor. 12. A method comprising pumping a fluid with a submergible pumping system including a pump and an electrical motor, wherein the electrical motor has a hollow rotor shaft and said pumping system is adapted to pump at least a portion of said fluid through said hollow rotor shaft, and wherein during operation at least a portion of said fluid passes in fluid contact with exterior portions of the electrical motor and removes heat therefrom wherein (a) the electrical motor has a hollow rotor shaft and the pumping system has a fluid intake below the electrical motor and in liquid communication with said hollow rotor shaft; (b) the pumping system has at least one outlet located at or below the electrical motor, said outlet being in liquid communication with the fluid intake, (c) the pumping system is submerged in a well having a well casing; (d) the cross-section that the electrical motor is such that the electrical motor fits within the well casing and a space is defined between the well casing and the electrical motor; and (e) said pumping system is adapted so that during operation a portion of the fluid entering the fluid intake is pumped though the hollow rotor shaft of the electrical motor, and a portion of the fluid entering the fluid intake is pumped through the outlet and upwardly in fluid contact with the outside of the electrical motor. 13. A method of pumping fluids, comprising (I) positioning a pumping system in a well with the pump being located between the electrical motor and the wellhead; wherein (a) electrical motor has a hollow rotor shaft which is in liquid communication with the pump, (a) the cross-section of the electrical motor is such that the electrical motor fits within the well casing and a space is defined between the well casing and the electrical motor; (b) the pumping system has a first fluid intake in liquid communication with said hollow rotor shaft; (c) the pumping system has a second fluid intake above the motor in liquid communication with the space defined between the well casing and the electrical motor, with the at least one outlet located at or below the electrical motor, said outlet being in liquid communication with the fluid intake; and (II) operating said pumping system under conditions such that during operation a portion of the fluids enter said first fluid intake and is pumped through the hollow rotor shaft of the electrical motor, and a second portion of the fluids are pumped through the space defined between the well casing and the electrical motor and in fluid contact with the exterior of the electrical motor to enter the second fluid intake, and said first and second portions of the fluids are then pumped to the wellhead. 14. A mechanism for providing motive force, the mechanism comprising (I) a power unit including: (a) a housing having an exterior wall; (b) a hollow rotor shaft having a longitudinal axis and opposite ends, the hollow rotor shaft being rotatably mounted within the housing for rotation of the hollow rotor shaft relative to the housing, substantially about the longitudinal axis of the hollow rotor shaft; and (c) a drive system mounted within said housing connected to the hollow rotor shaft for causing rotation of the hollow rotor shaft relative to the housing, wherein the drive system includes a plurality of magnets mounted within the housing, located around the hollow rotor shaft, wherein the magnets create magnetic forces for causing the hollow rotor shaft to rotate relative to the housing; and (II) a pumping unit located below the power unit, wherein (i) the pumping unit includes a longitudinal hollow drive shaft that is in fluid communication with the hollow rotor shaft in the power unit, the hollow drive shaft being rotated substantially about its longitudinal axis when the hollow rotor shaft of the power unit is rotated; (ii) the hollow drive shaft of the pumping unit has a shaft inlet proximate to its bottom, portion for allowing fluids being pumped to enter the hollow drive shaft; (iii) at least one impeller mounted to the exterior of the hollow drive shaft of the pumping unit such that when the hollow drive shaft is rotated, the impeller pumps fluids downwardly toward the inlet in the hollow drive shaft; and (iv) the pumping unit has fluid intakes proximate to a topmost portion thereof through which fluids being pumped enter the pumping unit; the fluid intakes, hollow drive shaft, shaft inlet and impellers being adapted such that when the hollow drive shaft is rotated about its longitudinal axis, fluids are pumped into the pumping unit through said fluid intakes, downwardly within the pumping unit to the shaft inlet, and then through the hollow drive shaft of the pumping unit and through the hollow rotor shaft of the power unit. 15. A method of removing a mixture of gaseous and liquid fluids from a well having at least one point where a mixture of gaseous and liquid fluids enter the well, comprising (I) positioning a pumping system in the well above the point or points where the mixture of gaseous and liquid fluids enter the well, wherein: (a) the pumping system includes at least one power unit, at least one pumping unit, and at least one intake through which fluids being pumped enter the pumping system; (b) the power unit includes a hollow rotor shaft in fluid communication said intake, and the pumping system is adapted such that fluids entering the intake are pumped through the hollow rotor shaft of the motor; (c) the power unit and pumping unit are smaller in diameter than the well; (d) the intake is located below at least a portion of the pumping system and is of smaller diameter than at least that portion of the pumping system above the intake; (e) the intake is adapted such that liquid fluids being pumped by the pumping system are caused to flow downwardly through a section of the intake to enter the pumping system; and (II) operating the pumping system such that (i) the gaseous fluids and the liquid fluids separate at a point proximate to the intake and below that portion of the pumping system above the intake, (ii) the gaseous fluids bypass the pumping system and rise to the surface of the well, and (iii) the liquid fluids being pumped flow upwardly to the intake, then downwardly through a section of the intake and then through the hollow rotor shaft of the motor and out of the well. 16. A method of pumping fluids with a submergible pumping system including a pump and an electrical motor, wherein the pumping system is submerged in production fluids such that said fluids flow across vortex generators adapted to impart streamwise vorticity to the production fluids as they pass in fluid contact with the exterior portions of the electrical motor wherein the vortex generators are attached to the exterior portions of the electric motor. 17. A method of pumping fluids with a submergible pumping system including a pump and an electrical motor, wherein the pumping system is submerged in production fluids such that said fluids flow across vortex generators adapted to impart streamwise vorticity to the production fluids as they pass in fluid contact with the exterior portions of the electrical motor wherein the vortex generators are attached to the interior surface of a motor shroud.