Flow-induced electrostatic power generator for downhole use in oil and gas wells

• US 8,511,373 B2
• Filed: 04/27/2011
• Issued: 08/20/2013
• Est. Priority Date: 04/27/2011
• Status: Active Grant

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Tosi, Luis Phillipe, Cornette, H. Mitchell, Underdown, David R.
• Primary Examiner(s): Stephenson, Daniel P
• Application Number:
  US13/094,964
• Publication Number:
  US 20120273235A1
• Time in Patent Office: 846 Days
• Field of Search: 166/65.1, 166/265, 310/309, 174/24, 209/54, 209/46
• US Class Current: 166/65.1
• CPC Class Codes: E21B 41/0085 Adaptations of electric power generating means for use in boreholes

Abstract

The present invention is directed to processes (methods) for harnessing flow-induced electrostatic energy in an oil and/or gas well and using this energy to power electrical devices (e.g., flowmeters, electrically-actuated valves, etc.) downhole. The present invention is also directed to corresponding systems through which such methods are implemented.

Claims

1. A method of powering devices in a petroleum well through the generation of electrostatic energy downhole, the petroleum well originating at a geological surface and being operable for the production of oil, natural gas, or mixtures thereof, said method comprising the steps of:

a) flowing a substantially non-conductive hydrocarbon-based fluid, as a flowstream, through a substantially insulating membrane;

b) generating a net, steady-state electrostatic potential between the flowstream and said membrane, wherein the membrane comprises a plurality of flow channels through which the substantially non-conductive hydrocarbon-based fluid can pass, and wherein at least a majority of said flow channels have an effective diameter of at least about 500 nm and at most about 200 μ

m;

c) harvesting electrical energy from the electrostatic potential via a ground electrode in electrical contact with the flowstream and an electrical lead in electrical contact with the membrane; and

d) using the electrical energy harvested in step (c) to power one or more devices downhole.

2. The method of claim 1, wherein the ground electrode take the form of a conductive mesh.

3. The method of claim 1, wherein the substantially non-conductive hydrocarbon-based fluid is selected from the group consisting of (a) completion fluid, (b) displacement fluid, (c) drilling fluid, and (d) combinations thereof.

4. The method of claim 1, wherein the substantially insulating membrane is comprised of a material selected from the group consisting of polytetrafluoroethylene (PTFE), polyamides (Nylon), polyimides, polyvinylchloride, polyolefins, polyesters, and combinations thereof.

5. The method of claim 1, wherein the net, steady-state electrostatic potential is at least about 0.5 mV and at most about 50 kV.

6. The method of claim 1, wherein the device deriving power from the harvested electrical energy is selected from the group consisting of one or more of the following:

a pressure sensor, a temperature sensor, a valve, telemetry electronics, flow meter, fluid sensing device, and combinations thereof.

7. The method of claim 1, wherein the device draws power from an electrical storage device that is, in turn, charged by the harvested electrical energy.

8. A system for powering devices in a petroleum well through the generation of electrostatic energy downhole, said system comprising:

a) a wellbore originating at a geological surface extending from a surface into a geological formation;

b) a plurality of tubular segments disposed within the wellbore, wherein said tubular segments are useful in conveying hydrocarbon-based fluids out of said wellbore;

c) at least one membrane-bearing tubular segment comprising;

i) an electrically-grounded outer upstream membrane electrode;

ii) an inner downstream membrane electrode;

iii) a dielectric filter membrane, comprising flow channels, disposed between the inner and outer membrane electrodes wherein at least a majority of said flow channels have an effective diameter of at least about 500 nm and at most about 200 μ

m;

d) at least one device-bearing tubular segment comprising at least one device that can be usefully employed downhole;

e) at least one electrical lead establishing connectivity between the inner downstream membrane electrode and the at least one device-bearing tubular segment;

f) a flow of substantially non-conductive hydrocarbon-based fluid, wherein said flow is directed through the tubular segments in an upward direction toward the surface;

wherein an electrical potential exists between the electrically-grounded outer upstream membrane electrode and the inner downstream membrane electrode, and wherein this electrical potential is harnessed to power at least one device in the at least one device-bearing tubular segment.

9. The system of claim 8, wherein the petroleum well is operable for producing oil, gas, or combinations thereof.

10. The system of claim 8, wherein the petroleum well is a multilateral well.

11. The system of claim 8, wherein the at least one device-bearing tubular segment comprises one or more devices selected from the group consisting of pressure sensors, temperature sensors, valves, telemetry electronics, flow meters, fluid sensing devices, and combinations thereof.

12. The system of claim 8, wherein the membrane-bearing tubular segment varies in length from at least about 10 cm to at most about 1000 m.

13. The system of claim 8, wherein each of the electrically-grounded outer upstream membrane electrode, the inner downstream membrane electrode, and the dielectric filter membrane, are of substantially the same length.

14. The system of claim 8, wherein the dielectric filter membrane is comprised of a material selected from the group consisting of polytetrafluoroethylene (PTFE), polyamides (Nylon), polyimides, polyvinylchloride, polyolefins, polyesters, and combinations thereof.

15. The system of claim 8, wherein one or more of the electrically-grounded outer upstream membrane electrode, the inner downstream membrane electrode, and the dielectric filter membrane, can additionally be used for purposes other than generating power.

16. The system of claim 8, wherein the at least one electrical lead can span a distance within the wellbore of up to 5,000 meters.

17. The system of claim 8, wherein the flow of substantially non-conductive hydrocarbon-based fluid comprises a fluid selected from the group consisting of heptanes, diesel, crude oil, mineral oil, and combinations thereof.

18. The system of claim 8, wherein the flow of substantially non-conductive hydrocarbon-based fluid possesses a flow rate of between about 1 liter/minute to about 5,000 liters/minute.

19. The system of claim 8, wherein electrical potential is harnessed by first charging an electrical storage device, and then using said electrical storage device to power the at least one device in the at least one device-bearing tubular segment.

20. The system of claim 8 further comprising a telemetry subsystem operable for conveying device-generated data to the surface.