Gas Meter With Adjustable Channel For Fugitive Emission Measurement
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Solution Overview
Problem
Current methods for measuring fugitive gas emissions from oil and gas wells, such as the 'bubble test', are inaccurate due to operator subjectivity, inability to distinguish between air and hydrocarbon emissions, and lack of direct measurement of flow rates, leading to incomplete quantification and qualification of methane emissions.
Innovation Solution
A gas meter with an adjustable channel portion that modifies cross-sectional area to control flow velocity, coupled with thermal mass flow measurement and gas property sensors to accurately measure flow rates and gas composition, enabling precise quantification and qualification of fugitive emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bubble test method is used to measure fugitive gas emissions, then the measurement process is simple and low-cost, but the measurement precision is poor due to operator subjectivity and inability to distinguish between air and hydrocarbon emissions
Solution Approach 1:
The patent replaces the manual bubble test method with an automated electronic flow meter that uses thermal conductivity sensors to directly measure gas flow rates. This substitution eliminates operator subjectivity and provides objective, quantifiable measurements while maintaining ease of field deployment.
Solution Approach 2:
The patent introduces a thermal conductivity sensor as an intermediary between the gas flow and the measurement system. This sensor detects the thermal properties of the gas to distinguish between air and hydrocarbon emissions, providing accurate identification and measurement without requiring direct operator intervention.
2Device complexity
If a fixed cross-sectional area channel is used in the flow meter, then the device structure is simple, but the adaptability is limited for measuring both low and high flow rates accurately
Solution Approach 1:
The patent implements a variable cross-sectional area channel with adjustable geometry that can be dynamically modified to match different flow rate conditions. This dynamic adjustment allows the flow meter to maintain measurement accuracy across a wide range of flow rates from very low to very high emissions.
Solution Approach 2:
The patent changes the geometric parameters of the channel, specifically the cross-sectional area, to optimize measurement for different flow conditions. By adjusting this physical parameter, the device can accurately measure both low flow rates from restricted vents and high flow rates from open vents.
3Measurement precision
If the cross-sectional area of the channel is modified to control flow velocity, then the measurement accuracy is improved, but the device complexity increases due to moveable parts
Solution Approach 1:
The patent divides the channel into multiple discrete cross-sectional area sections that can be independently selected or adjusted. This segmentation allows the device to achieve variable geometry through discrete configurations rather than continuous complex mechanisms, reducing overall device complexity while maintaining measurement precision.
4Measurement precision
If thermal mass flow measurement is used, then the measurement precision for low flow rates is improved, but the use of energy increases due to thermal sensing requirements
Solution Approach 1:
The patent utilizes thermal conductivity variations in the gas phase to detect flow rates. By measuring the thermal properties of the gas without requiring phase changes or extreme temperature conditions, the system achieves high precision low flow rate measurement with minimal energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides accurate and reliable measurement of low and high flow rates, distinguishing between hydrocarbon and non-hydrocarbon gases, and allows for real-time data transmission, enhancing regulatory compliance and environmental monitoring.
Implementation Method 1
a thermal mass flow meter positioned within the adjustable channel and which measures the mass flow rate by heating a portion of the flowing fluid and then recording how that heat is dispersed by the flow
Data Source
Figure 1a~1c
Figure 1d
Figure 2a~2b
AI summary
A device which: optically detects the presence of, measures the flow rate of, and identifies the characteristics of venting fugitive gas emissions. Specifically the device provides a spectral analysis of emission gas constituents; selective detection of the presence of venting hydrocarbons; measurement of venting emissions flow rates, the measurement of shut-in and flowing venting system pressures and the venting system temperatures. The flow rates are corrected, relative to the detection of the gas constituents and standard temperature and pressure (STP). These devices are configured to collect such data electronically and transmit via various telemetry systems, to a secure remote data network for reporting, access, evaluation, real-time monitoring and archiving as required.