Energy storing hydraulic lift pump for oil wells

• US 4,724,672 A
• Filed: 06/23/1986
• Issued: 02/16/1988
• Est. Priority Date: 06/23/1986
• Status: Expired due to Fees

• Current Assignee: Peter B. Olmsted
• Original Assignee: Peter B. Olmsted
• Inventors: Olmsted, Peter B.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US06/877,490
• Time in Patent Office: 603 Days
• Field of Search: 60/413, 60/414, 60/371
• US Class Current: 60/371
• CPC Class Codes: E21B 43/129 Adaptations of down-hole pump systems powered by fluid supplied from outside the borehole gas-lift E21B43/122; jet pumps E21B43/124
• CPC Class Codes: F04B 47/04 the driving means incorporating fluid means
• CPC Class Codes: F04B 47/14 Counterbalancing
• CPC Class Codes: F04B 49/002 Hydraulic systems to change the pump delivery

Abstract

A motor driven hydraulic lift pump assembly for oil wells includes a mechanical flywheel connected to a hydraulic pump/motor combination in turn incorporated in the hydraulic circuit of the well lift cylinder. The pump/motor and flywheel assembly with associated hydraulic control can be separately mounted on a skid and connected into the hydraulic and electrical circuitry for the well lift cylinder. The combination pump/motor reverses in mode as the vertically mounted well cylinder piston moves upwardly and downwardly to pump from a deep well. As the well cylinder piston moves downwardly the pump/motor is in motor mode storing energy by increasing the rotational speed of the flywheel. As the well cylinder piston moves upwardly the pump/motor is in the pump mode and energy is taken from the flywheel to assist in raising the well cylinder piston to pump crude oil from the deep well. Thus, a portion of the energy released as the well cylinder piston moves downwardly on the return stroke is saved in the flywheel and recycled to assist in raising the well cylinder on the pumping stroke.

Claims

1. An energy storable source and sink for high pressure hydraulic fluid comprising,

high pressure hydraulic fluid input/output supply means and low pressure hydraulic fluid input/output supply means,

a hydraulic pump communicating between the high pressure supply means and the low pressure supply means, a hydraulic pump/motor communicating between the high pressure supply means and the low pressure supply means, said pump/motor being connected between the two supply means in parallel with the pump,

pump control means connected to the pump and adapted to selectably cause the pump to provide high pressure fluid to the high pressure supply means,

pump/motor control means connected to the pump/motor and adapted to selectably cause the pump/motor to provide high pressure fluid to the high pressure supply means or to accept high pressure fluid from the supply means, and

a rotatable mass, a rotatable shaft connected to said rotatable mass, said rotatable shaft mechanically connected to said pump/motor in driving engagement therewith.

2. The energy storable source and sink of claim 1 wherein said pump comprises a variable flow pump.

3. The energy storable source and sink of claim 1 wherein said pump/motor comprises a variable flow pump/motor.

4. The energy storable source and sink of claim 3 wherein said pump/motor control means includes means to change the fluid flow rate through said pump/motor in response to a change in fluid flow through the pump.

5. An energy storing well lift pump comprising,

hydraulic well lift means generally positionable above a well head and attachable to a pump rod extending downwardly into the well for vertical reciprocating movement of the pump rod,

high pressure hydraulic fluid input/output supply means in communication with the well lift means and low pressure hydraulic fluid input/output supply means in communication with the well lift means,

a hydraulic pump communicating between the high pressure supply means and the low pressure supply means, a hydraulic pump/motor communicating between the high pressure supply means and the low pressure supply means, said pump-motor being connected between the two supply means in parallel with the pump,

pump control means connected to the pump and adapted to selectably cause the pump to provide high pressure fluid to the high pressure supply means,

pump/motor control means connected to the pump/motor and adapted to selectably cause the pump/motor to provide high pressure fluid to the high pressure supply means or to accept high pressure fluid from the supply means, and

a rotatable mass, a rotatable shaft connected to said rotatable mass, said rotatable shaft mechanically connected to said pump/motor in driving engagement therewith.

6. The energy storing well lift pump of claim 5 wherein said hydraulic pump comprises a variable flow pump having variable flow control servos thereon and said pump control means comprises a source of pressurized fluid, pilot conduit means connecting the source of pressurized fluid to the pump control servos and valve means interposed in the pilot conduit means to selectably actuate the pump control servos.

7. The energy storing well lift pump of claim 5 wherein said hydraulic pump/motor comprises a variable flow pump/motor having variable flow control servos thereon and said pump/motor control means comprises a source of pressurized fluid, pilot conduit means connecting the source of pressurized fluid to the pump/motor control servos and valve means interposed in the pilot conduit means to selectably actuate the pump/motor control servos.

8. The energy storing well lift pump of claim 5 wherein said well lift means comprises a hydraulic cylinder vertically mountable above a well head with the pump rod actuatable by the piston of the hydraulic cylinder.