Enhancing coal seam gas pressure measurement accuracy and preventing leakage through dual chamber pressure balancing in borehole
Document Type
Journal Article
Publication Title
Gas Science and Engineering
Volume
129
Publisher
Elsevier
School
Centre for Sustainable Energy and Resources / School of Engineering
Funders
National Natural Science Foundation of China / Natural Science Foundation of Henan Province / Scientific and Technological Research Project in Henan Province / Fundamental Research Funds for the Universities of Henan Province
Grant Number
52304083, 42202210, 232300420303, 232102320336, NSFRF220441
Abstract
Accurate measurement of coal seam gas pressure (CSGP) is critical to the evaluation of coal mine gas hazards and the potential of coal seam gas extraction. In this study, we investigate gas leakage from chambers and its influences on CSGP measurement results (MR) through numerical simulations. Furthermore, we propose, analyze and validate a novel method that balances gas pressure between two chambers, i.e. the measurement and regulation chambers, in a borehole. The results demonstrate that: (1) Traditional CSGP measurement method utilizing boreholes with a single chamber exhibit a gradual expansion of the gas pressure dropping region around the borehole, accompanied by an initial increase in chamber gas pressure followed by stabilization. The gas leakage process within the chamber undergoes three typical stages. (2) The increase of gas leakage lowers the MR value and raises the CSGP measurement error ratio (R). The relationship between MR, R and the stable value of gas leakage is nearly linear. (3) The proposed novel CSGP measurement method involves continuous gas injection into the regulation chamber to establish a dynamic gas pressure balance region between the two chambers. This approach minimizes gas leakage in the measurement chamber and accelerates gas pressure recovery. Maintaining dynamic pressure equality between the dual chambers is essential for minimizing R. (4) An automatic regulation unit is developed to achieve dynamic gas pressure balancing between the two chambers. With the novel method, R values remain below 3%, yielding higher CSGP measurement accuracy compared to alternative approaches.
DOI
10.1016/j.jgsce.2024.205413
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Comments
Wang, Z., Sun, Y., Li, Z., Sun, Z., Zhang, S., Ding, L., & You, Z. (2024). Enhancing coal seam gas pressure measurement accuracy and preventing leakage through dual chamber pressure balancing in borehole. Gas Science and Engineering, 129, 205413. https://doi.org/10.1016/j.jgsce.2024.205413