Systems and methods for determining a survey area for gas leak detection

• US 10,330,555 B1
• Filed: 04/25/2016
• Issued: 06/25/2019
• Est. Priority Date: 05/14/2012
• Status: Active Grant

• Current Assignee: Picarro, Inc.
• Original Assignee: Picarro, Inc.
• Inventors: Tan, Sze M., Rella, Chris W.
• Primary Examiner(s): Islam, Mohammad K
• Application Number:
  US15/137,550
• Time in Patent Office: 1,156 Days
• CPC Class Codes: F02M 65/006 Measuring or detecting fuel leakage of fuel injection apparatus
• CPC Class Codes: G01M 3/00 Investigating fluid-tightness of structures
• CPC Class Codes: G01M 3/007 Leak detector calibration, standard leaks G01M3/207 takes precedence
• CPC Class Codes: G01M 3/04 by detecting the presence of fluid at the leakage point
• CPC Class Codes: G01M 3/16 using electric detection means G01M3/045, G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence
• CPC Class Codes: G01M 3/24 using infrasonic, sonic, or ultrasonic vibrations
• CPC Class Codes: G01M 3/26 by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
• CPC Class Codes: G01M 3/28 for pipes, cables or tubes; for pipe joints or seals; for valves ; for welds
• CPC Class Codes: G01M 3/2807 for pipes G01M3/2892, G01M3/30 take precedence
• CPC Class Codes: G01M 3/2892 for underground fuel dispensing systems G01M3/30 takes precedence
• CPC Class Codes: G01M 3/38 by using light G01M3/02 takes precedence
• CPC Class Codes: G01W 1/00 Meteorology
• CPC Class Codes: G06F 15/00 Digital computers in general details G06F1/00 – G06F13/00; Data processing equipment in general
• CPC Class Codes: G06F 16/29 Geographical information databases

Abstract

In some embodiments, at least one processor is employed to determine a boundary of a survey area. Data representative of the locations of measurement points adjacent to or outside of the survey area is received, as well as data representative of wind direction at the measurement points. The boundary of the survey area is determined according to the data representative of wind direction and a maximum detection distance value representative of an estimated maximum distance from a potential gas leak source at which a gas leak from the potential source can be detected. The boundary is determined such that if the potential gas leak source is located in the survey area and has a rate of leakage meeting a minimum leak rate condition, then an estimated probability of detection of the gas leak at one or more of the measurement points satisfies a probability condition.

Claims

1. A method comprising:

performing a gas leak detection survey by measuring one or more gas concentration values at one or more measurement points using a gas concentration measurement device carried by a moving vehicle along a survey path;

employing at least one hardware processor to determine a maximum detection distance value for one or more measurement points along the survey path, the maximum detection distance value being determined according to data representative of wind direction at the one or more measurement points, wherein the maximum detection distance value is representative of an estimated maximum distance from a potential gas leak source at which a gas leak from the potential gas leak source is detectable by the survey at the one or more measurement points; and

employing the least one hardware processor to determine a boundary of a survey area for the gas leak detection survey according to the maximum detection distance value—

wherein the boundary of the survey area is determined such that if the potential gas leak source is located in the survey area and has a rate of leakage meeting a minimum leak rate condition, then an estimated probability of detection of the gas leak at the one or more measurement point satisfies a probability condition, wherein determining the boundary of the survey area comprises computing an estimated probability of detection of the gas leak at the one or more measurement points, and comparing the estimated probability of detection to a threshold, the threshold being greater than or equal to 50%.

2. The method of claim 1, wherein the probability of detection at the one or more of the measurement points is estimated according to an angle subtended by a segment of the survey path relative to a candidate point for the potential gas leak source, the segment of the survey path being positioned within a distance of the candidate point that is less than or equal to the estimated maximum distance.

3. The method of claim 2, wherein the probability of detection is further estimated according to a cumulative probability of wind directions with respect to the subtended angle.

4. The method of claim 3, wherein the data representative of wind direction comprises a plurality of wind direction measurements, and wherein the cumulative probability of wind directions is determined according to a representative wind direction and a wind direction variability calculated from the wind direction measurements.

5. The method of claim 4, wherein the representative wind direction comprises a mean, median, or mode of the wind direction measurements, and wherein the wind direction variability comprises a variance or standard deviation of the wind direction measurements.

6. The method of claim 1, wherein the maximum detection distance value is determined according to data representative of wind speed at the one or more measurement points.

7. The method of claim 6, wherein the maximum detection distance value is further determined according to data representative of atmospheric stability conditions at the one or more measurement points.

8. The method of claim 1, wherein the threshold is greater than or equal to 70%.

9. The method of claim 1, wherein performing the gas leak detection survey comprises performing a set of wind measurements using a wind measurement device carried by the moving vehicle, for generating the data representative of wind direction.

10. An apparatus comprising:

a gas concentration measurement device configured to measure one or more gas concentration values at one or more measurement points along a survey path traveled by a moving vehicle conducting a gas leak detection survey, the vehicle carrying the gas concentration measurement device; and

at least one hardware processor coupled to the gas concentration measurement device and configured to;

determine a maximum detection distance value for one or more measurement points along the survey path the maximum detection distance value being determined according to data representative of wind direction at the one or more measurement points, wherein the maximum detection distance value is representative of an estimated maximum distance from a potential gas leak source at which a gas leak from the potential gas leak source is detectable by the survey at the one or more measurement points; and

determine a boundary of a survey area for the gas leak detection survey according to the maximum detection distance value wherein determining the boundary of the survey area comprises computing an estimated probability of detection of the gas leak at the one or more measurement points, and comparing the estimated probability of detection to a threshold, the threshold being greater than or equal to 50%.

11. The apparatus of claim 10, the probability of detection at the one or more measurement points is estimated according to an angle subtended by a segment of the survey path relative to a candidate point for the potential gas leak source, the segment of the survey path being positioned within a distance of the candidate point that is less than or equal to the estimated maximum distance.

12. The apparatus of claim 11, wherein the probability of detection is further estimated according to a cumulative probability of wind directions with respect to the subtended angle.

13. The apparatus of claim 12, wherein the data representative of wind direction comprises a plurality of wind direction measurements, and wherein the cumulative probability of wind directions is determined according to a representative wind direction and a wind direction variability calculated from the wind direction measurements.

14. The apparatus of claim 13, wherein the representative wind direction comprises a mean, median, or mode of the wind direction measurements, and wherein the wind direction variability comprises a variance or standard deviation of the wind direction measurements.

15. The apparatus of claim 10, wherein the maximum detection distance value is determined according to data representative of wind speed at the one or more measurement points.

16. The apparatus of claim 15, wherein the maximum detection distance value is further determined according to data representative of atmospheric stability conditions at the one or more measurement points.

17. The apparatus of claim 10, wherein the threshold is greater than or equal to 70%.

18. The apparatus of claim 10, further comprising a wind measurement device configured to perform a set of wind measurements for generating the data representative of wind direction.

19. A non-transitory computer-readable medium encoding instructions which, when executed by a computer system, cause the computer system to:

receive one or more gas concentration values measured at one or more measurement points by a gas concentration measurement device carried by a moving vehicle along a survey path;

determine a maximum detection distance value for one or more measurement points along the survey path, the maximum detection distance value being determined according to data representative of wind direction at the one or more measurement points, wherein the maximum detection distance value is representative of an estimated maximum distance from a potential gas leak source at which a gas leak from the potential gas leak source is detectable by the survey at the one or more measurement points; and

determine a boundary of a survey area for the gas leak detection survey according to the maximum detection distance value, wherein determining the boundary of the survey area comprises computing an estimated probability of detection of the gas leak at the one or more measurement points, and comparing the estimated probability of detection to a threshold, the threshold being greater than or equal to 50%.