ACOUSTIC SENSING SYSTEM FOR DETERMINING AN INTERFACE BETWEEN TWO MATERIALS

• US 20140160888A1
• Filed: 12/12/2012
• Published: 06/12/2014
• Est. Priority Date: 12/12/2012
• Status: Active Grant

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Childers, Brooks, Duncan, Roger
• Granted Patent: US 9,213,121 B2
• Time in Patent Office: Days
• US Class Current: 367/25
• CPC Class Codes: E21B 47/047 Liquid level measuring depth or liquid level using radioactive markers E21B47/053
• CPC Class Codes: G01F 23/292 Light , e.g. infrared or ultraviolet
• CPC Class Codes: G01F 23/2927 for several discrete levels, e.g. with more than one light-conducting sensing element
• CPC Class Codes: G01H 9/004 using fibre optic sensors light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125
• CPC Class Codes: G01V 1/40 specially adapted for well-logging
• CPC Class Codes: G01V 1/48 Processing data

Abstract

A system for locating an interface between a first material and a second material including one or more acoustic sensing elements operatively arranged to measure a characteristic of one or more acoustic signals at a plurality of locations along a length thereof. An instrumentation unit is coupled with the one or more acoustic sensing elements, and arranged to determine a difference between at least a first value of the characteristic measured at a first location and a second value of the characteristic measured at a second location of the plurality of locations for identifying the interface between the first material and the second material as being located between the first and second locations if the difference is greater than a preselected threshold amount. A method of locating an interface is also included.

Claims

1. A system for locating an interface between a first material and a second material, comprising:

one or more acoustic sensing elements operatively arranged to measure a characteristic of one or more acoustic signals at a plurality of locations along a length of the one or more acoustic sensing elements; and

an instrumentation unit coupled with the one or more acoustic sensing elements, the instrumentation unit operatively arranged to determine a difference between a first value of the characteristic measured at a first location of the plurality of locations and a second value of the characteristic measured at a second location of the plurality of locations for identifying the interface between the first material and the second material as being located between the first and second locations if the difference is greater than a preselected threshold amount.

2. The system of claim 1, wherein the one or more acoustic sensing elements comprises one or more optical fibers.

3. The system of claim 2, wherein the one or more optical fibers are arranged with one or more fiber Bragg gratings.

4. The system of claim 2, wherein the one or more optical fibers are arranged for distributed acoustic sensing.

5. The system of claim 1, wherein the difference is associated with a change in acoustic coupling between the first and second materials.

7. The system of claim 1, wherein the characteristic is amplitude, frequency, wavelength, or a combination including at least one of the foregoing.

8. The system of claim 1, further comprising one or more noise producing devices operatively arranged for producing the acoustic signal.

9. The system of claim 8, wherein the one or more noise producing devices produce the acoustic signal having known values for the characteristic.

10. The system of claim 1, wherein the volume is defined by a storage tank or vessel.

11. The system of claim 1, wherein the first or second materials relate to performance of a downhole operation and include treatment fluids, stimulation fluids, proppant, drilling mud additives, or a combination including at least one of the foregoing.

12. The system of claim 1, wherein the volume is defined by a borehole.

13. The system of claim 12, wherein the interface is associated with a boundary between a water-bearing zone and an oil-bearing zone proximate to the borehole.

6. The system of claim 6, wherein the one or more acoustic elements are one or more optical fibers and the instrumentation unit is an optical frequency-domain reflectometry instrument.

14. A method of locating an interface between a first material and a second material, comprising:

measuring a characteristic of one or more acoustic signals with one or more acoustic sensing elements at a plurality of locations within a volume; and

comparing a first value of the characteristic measured at a first location of the plurality of locations with a second value of the characteristic measured at a second location of the plurality of locations; and

determining the interface between the first material and the second material to be located between the first location and the second location if the first and second values differ by at least a preselected threshold amount.

15. The method of claim 14, wherein the one or more acoustic sensing elements are one or more optical fibers.

16. The method of claim 14, further comprising comparing a third value of the characteristic measured at a third location of the plurality of locations with the first or second values and determining a second interface to be located if a second difference between the third value and the first or second values differs by at least a second preselected threshold amount.

17. The method of claim 14, further comprising producing the acoustic signal with one or more noise producing devices.

18. The system of claim 14, wherein the comparing and the determining are performed by an instrumentation unit coupled to the one or more acoustic elements.