System and method for sensing a liquid level

• US 8,353,677 B2
• Filed: 10/05/2009
• Issued: 01/15/2013
• Est. Priority Date: 10/05/2009
• Status: Active Grant

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Thompson, M. Clark, Webb, Charles H.
• Primary Examiner(s): FREAY, CHARLES GRANT
• Application Number:
  US12/573,434
• Publication Number:
  US 20110081256A1
• Time in Patent Office: 1,198 Days
• Field of Search: 417/36, 417/423.3, 166/250.03
• US Class Current: 417/36
• CPC Class Codes: E21B 47/047 Liquid level measuring depth or liquid level using radioactive markers E21B47/053
• CPC Class Codes: F04B 47/00 Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps by using positive or negative pressurised fluid medium acting directly on the liquid to be pumped F04F1/00
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: G01F 23/22 by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water involving the use of floats G01F23/30
• CPC Class Codes: G01F 23/284 Electromagnetic waves

Abstract

A system, method and device may be used to monitor fluid levels in a borehole. The system includes a pulse generator to generate a pulse of electromagnetic energy to propagate along the wellbore towards a surface of the fluid, a detector to detect a portion of the electromagnetic pulse reflected from the surface of the fluid and propagated along the wellbore towards the detector, a processor to analyze detected signals to determine a level of the surface of the fluid, and a pump controller to control the operation of a pump located in the wellbore based on the fluid surface level.

Claims

1. A system for measuring a fluid level in a casing-lined wellbore, comprising:

a pulse generator, positionable and operable to generate a pulse of electromagnetic energy to propagate along the wellbore towards a surface of the fluid;

a detector, positionable and operable to detect a portion of the electromagnetic pulse reflected from the surface of the fluid and propagated along the wellbore towards the detector;

a processor, configured and arranged to receive a signal from the detector representative of the detected portion of the electromagnetic pulse and to analyze it to determine a level of the surface of the fluid; and

a pump controller, configured and arranged to receive distance information from the processor and to use the distance information to control the operation of a pump located in the wellbore and wherein the detector is configured to power off once the detector detects the portion of electromagnetic pulse reflected from the surface.

2. A system as in claim 1, wherein the pump controller reduces pump capacity when the distance information indicates that the fluid level is near a pump level in the wellbore.

3. A system as in claim 1, wherein the pump controller stops the pump when the distance information indicates that the fluid level is at or below a pump level in the wellbore.

4. A system as in claim 1, wherein the pump controller increases pump capacity when the distance information indicates that the fluid level is at a level greater than a selected amount greater than the pump level.

5. A system as in claim 1, wherein the processor is further configured and arranged to analyze the signals to obtain information relating to a composition of the fluid based on an amplitude of the detected portion.

6. A system as in claim 5, wherein the composition information comprises a proportion of water to hydrocarbon.

7. A system as in claim 1, wherein a rate of change of successive distance information measurements is used to determine whether the fluid level is rising or falling, and the pump controller further controls the operation of the pump based on the direction of change of the fluid level.

8. A system as in claim 1, wherein a rate of change of successive distance information measurements is used to determine whether the fluid level is rising or falling, and the pump controller further controls the operation of the pump based on a magnitude of change of the fluid level.

9. The system as in claim 1, wherein the detector is configured to be powered on during a time window delayed with respect to the generation of electromagnetic energy.

10. A method for controlling a pump located in a casing-lined wellbore comprising:

generating a pulse of electromagnetic energy to propagate along the wellbore towards a surface of the fluid;

detecting with a detector a portion of the electromagnetic pulse reflected from the surface of the fluid and propagated along the wellbore towards the detector;

receiving a signal from the detector representative of the detected portion of the electromagnetic pulse;

analyzing the signal to determine a level of the surface of the fluid; and

controlling the operation of the pump, based on the determined surface level of the fluid wherein the detector is configured to power off once the detector detects the portion of electromagnetic pulse reflected from the surface.

11. A method as in claim 10, wherein the controlling comprises reducing pump capacity when the determined surface level is near a pump level in the wellbore.

12. A method as in claim 10, wherein the controlling comprises stopping the pump when the distance information indicates that the fluid level is at or below a pump level in the wellbore.

13. A method as in claim 10, wherein the controlling comprises increasing pump capacity when the distance information indicates that the fluid level is at a level greater than a selected amount greater than the pump level.

14. A method as in claim 10, further comprising determining information relating to a composition of the fluid based on an amplitude of the detected portion.

15. A method as in claim 14, wherein the composition information comprises a proportion of water to hydrocarbon.

16. A method as in claim 10, wherein the controlling further comprises controlling the operation of the pump based on a direction of change of the fluid level over successive measurements.

17. A method as in claim 10, wherein the controlling further comprises controlling the operation of the pump based on a magnitude of change of the fluid level over successive measurements.

18. The method as in claim 10, wherein the detector is configured to be powered on during a time window delayed with respect to the generation of electromagnetic energy.