Experimental studies on gas and water permeability of fault rocks from the rupture of the 2008 Wenchuan earthquake, China
Experimental studies on gas and water permeability of fault rocks from the rupture of the 2008 Wenchuan earthquake, China
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DOI：
10.1007/s11430-014-4948-7
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发表时间：
2014-09
期刊：
影响因子：
--
通讯作者：
Qingbao Duan;Xiaosong Yang
中科院分区：
文献类型：
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作者：
Qingbao Duan;Xiaosong Yang
以氮气和蒸馏水为孔隙流体，在20 ~ 180 MPa的围压范围内，对汶川地震破裂带断层岩的渗透率进行了室温下的测定。实验结果表明，随着围压的增加，气体渗透率和水渗透率均呈幂律关系减小，B= 0.2×10−3kl−0.557。水渗透率比气体渗透率小一个数量级，也比通过Klinkenberg效应校正的渗透率小半个数量级，即所谓的本征渗透率。渗透率的差异表明，除了Klinkenberg效应外，水分子粘附在粘土颗粒表面和膨胀性粘土矿物的水膨胀引起的有效孔径减小也有助于降低水渗透率。因此，断层岩的液体渗透率不能通过克林肯伯格修正的气体渗透率可靠、准确地推导出来，需要以液体作为孔隙介质直接测量其输运性质。
The permeabilities of fault rocks from the rupture of Wenchuan earthquake were measured by using nitrogen gas and distilled water as pore fluids under the confining pressure ranging from 20 to 180 MPa at room temperature. Experimental results indicate that both gas and water permeabilities decrease with increasing confining pressure, described by power law relationship, i.e.,b= 0.2×10−3kl−0.557. The water permeability is about one order less than gas permeability and also half order smaller than the permeability corrected by the Klinkenberg effect, so-called intrinsic permeability. The differences in the permeabilies imply that the reduction of effective pore size caused by the adhesion of water molecules to clay particle surface and water-swelling of expandable clay minerals contributes to lessening the water permeability besides the Klinkenberg effect. Hence, the liquid permeability of fault rocks cannot be deduced by gas permeability by the Klinkenberg correction reliably and accurately, and it is necessary to use liquid as pore media to measure their transport property directly.