Affiliation:
1. Institute of Geology and Geochemistry of Petroleum and Coal, Energy and Mineral Resources Group (EMR), RWTH Aachen University, Lochnerstrasse 4-20, D-52056 Aachen, Germany
Abstract
AbstractIn order to characterize the stress-dependence of porosity and permeability of Bossier shale, a series of measurements was conducted on three dry, horizontally orientated samples using various gases under controlled stress conditions.The Klinkenberg-corrected permeability and gas slippage factors varied by more than two orders of magnitude (0.21–86 µD) and by one order of magnitude (0.09–0.89 MPa), respectively. Porosity values measured under in situ stress conditions were lower by up to 30% than those measured at ambient conditions. Therefore, disregarding the stress-dependence of porosity may lead to a substantial overestimation of the free gas storage capacity.The stress sensitivity of Klinkenberg-corrected permeability coefficients (−0.012–−0.063MPa−1) is much larger than the stress sensitivity of porosity (−0.0014–−0.0033 MPa−1). Particularly for pore systems dominated by microfractures or slit-shaped pores, the permeability is highly sensitive to effective stress changes. While conventional pore models use porosity stress-sensitivity exponents (m) ranging between 3 and 5, we measured values of up to 27. Strongly stress-sensitive permeability behaviour is a result of effective stress preferentially reducing the volume and effective cross-section of transport pathways. In contrast, stress-dependent permeability of a less stress-sensitive sample is instead controlled by the redistribution of flow.
Publisher
Geological Society of London
Subject
Geology,Ocean Engineering,Water Science and Technology
Reference68 articles.
1. Variation of gas flow properties in coal with probe gas, composition and fabric: examples from western Canadian sedimentary basin;International Journal of Coal Geology, Advances in Organic Petrology,2013
2. Density, porosity, and compaction of sedimentary rocks;American Association of Petroleum Geologists Bulletin,1930
3. Compaction curves;American Association of Petroleum Geologists Bulletin,1985
4. Predicting capillarity of mudrocks;Marine and Petroleum Geology,2013
5. CBM and CO2-ECBM related sorption processes in coal: A review
Cited by
35 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献