Revaluating coal permeability-gas pressure relation under various gas pressure differential conditions
نویسندگان
چکیده
Abstract Identifying changes in coal permeability with gas pressure and accurately codifying mean effective stresses laboratory samples are crucial predicting gas-flow behavior reservoirs. Traditionally, to is assessed using the steady-state method, where equivalent indexed average of upstream downstream pressures coal, while ignoring nonlinear gradient along flow path. For a compressible gas, traditional method consistently underestimates length/volume-averaged overestimates stress. The higher differential within sample, greater error between true for fluid that assumed as under typical reservoir conditions. A correction coefficient asymptotes approximately 1.3%, representing stress can be on order 30%, particularly highly pressure-sensitive permeabilities compressibilities, further amplifying errors evaluated properties. We utilized this volume-averaged correct compressibility data reported literature. Both corrected initial pore were found smaller than uncorrected values, due underestimation pressure, resulting an overestimation if not corrected. ranges from 0.6 0.1 (reservoir values only 40% 90% values), remains at 0.75 25% value). Errors parameters quantified various factors, such confining sorption, temperature. By analyzing evolutions compressibility, coupling mechanisms mechanical compression, adsorption swelling, thermal expansion structure interpreted. These findings provide insights useful assessing sensitivity truly representative
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ژورنال
عنوان ژورنال: International Journal of Coal Science & Technology
سال: 2023
ISSN: ['2095-8293']
DOI: https://doi.org/10.1007/s40789-023-00609-1