Linear Hydraulic Pump for Submersible Applications

1 . A submersible pumping system comprising:

an electric motor;

a rotary hydraulic pump driven by the electric motor, wherein the rotary hydraulic pump produces a pressurized working fluid; and

a linear hydraulic pump that is configured to move a production fluid, wherein the linear hydraulic pump is driven by the pressurized working fluid.

2 . The submersible pumping system of claim 1 , wherein the rotary hydraulic pump comprises:

a rotatable pump shaft driven the electric motor;

a plurality of linearly reciprocating piston assemblies; and

a tilt disc assembly connected to the rotatable pump shaft and to the plurality of linearly reciprocating piston assemblies.

3 . The submersible pumping system of claim 2 , wherein the tilt disc assembly further comprises:

a drive plate; and

a rocker plate.

4 . The submersible pumping system of claim 1 , wherein the rotary hydraulic pump comprises:

a rotatable pump shaft driven the electric motor;

a plurality of linearly reciprocating piston assemblies; and

a camshaft assembly connected to the rotatable pump shaft and to the plurality of linearly reciprocating piston assemblies.

5 . The submersible pumping system of claim 4 , wherein the camshaft assembly comprises:

a camshaft;

a plurality of lobes on the camshaft; and

a plurality of connecting rods, wherein each of the plurality of connecting rods is connected to a different one of the plurality of linearly reciprocating piston assemblies.

6 . The submersible pumping system of claim 5 , wherein the lobes on the camshaft have a stepped profile that causes the plurality of linearly reciprocating piston assemblies to sequentially reciprocate in a manner that produces a progressive cavity within each of the plurality of manifolds.

7 . The submersible pumping system of claim 1 , wherein the linear hydraulic pump comprises:

a master cylinder in fluid communication with the pressurized working fluid;

a master piston within the master cylinder;

a slave cylinder in fluid communication with the production fluid; and

a slave piston within the slave cylinder, wherein the slave piston is operably connected to the master piston.

8 . The submersible pumping system of claim 7 , wherein the linear hydraulic pump further comprises:

upper and lower injection ports in fluid communication with the master cylinder;

upper and lower vents in fluid communication with the master cylinder;

a lower valve plate; and

an upper valve plate.

9 . The submersible pumping system of claim 7 , further comprising a pushrod connected between the master piston and the slave piston.

10 . The submersible pumping system of claim 1 , further comprising a seal section positioned between the pump and the motor.

11 . The submersible pumping system of claim 1 , further comprising a one or more working fluid lines connected between the rotary hydraulic pump and the linear hydraulic pump, wherein the working fluid lines provide a conduit for the pressurized working fluid.

12 . The submersible pumping system of claim 11 , wherein the working fluid lines are internal working fluid lines.

13 . The submersible pumping system of claim 11 , wherein the working fluid lines are external working fluid lines.

14 . A submersible pumping system disposed in a wellbore, the submersible pumping system comprising:

an electric motor, wherein the electric motor is filled with a motor lubricant fluid;

a hydraulic pump driven by the electric motor, wherein the hydraulic pump increases the pressure of the motor lubricant fluid; and

a production pump configured to produce a production fluid from the wellbore, wherein the production is driven by the pressurized motor lubricant fluid.

15 . The submersible pumping system of claim 14 , wherein the production pump comprises:

a master cylinder in fluid communication with the pressurized motor lubricant fluid;

a master piston configured for linear reciprocating movement within the master cylinder;

a slave cylinder in fluid communication with the production fluid; and

a slave piston within the slave cylinder, wherein the slave piston moves in response to the movement of the master piston.

16 . The submersible pumping system of claim 15 , wherein the production pump further comprises:

upper and lower injection ports in fluid communication with the master cylinder;

upper and lower vents in fluid communication with the master cylinder;

a lower valve plate; and

an upper valve plate.

17 . The submersible pumping system of claim 15 , wherein the production pump further comprises a pushrod connected between the master piston and the slave piston.

18 . A method for controlling the temperature of an electric motor within a submersible pumping system disposed in a wellbore, the method comprising the steps of:

providing an electric motor that is filled with motor lubricant fluid at a first temperature;

driving a hydraulic pump with the electric motor;

pumping the motor lubricant fluid with the hydraulic pump from the electric motor to a production pump;

driving the production pump with the motor lubricant fluid to evacuate a production fluid from the wellbore; and

providing the return of the motor lubricant fluid from the production pump to the electric motor at second temperature that is lower than the first temperature.

19 . The method of claim 18 , wherein the step of pumping the motor lubricant to the production pump further comprises pumping the motor lubricant to the linear hydraulic pump through an external working fluid line.

20 . The method of claim 18 , wherein the step of pumping the motor lubricant to the linear hydraulic pump further comprises pumping the motor lubricant to the linear hydraulic pump through an internal working fluid line.