Anisotropy of permeability in faulted porous sandstones
Anisotropy of permeability in faulted porous sandstones
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DOI：
10.1016/j.jsg.2014.02.008
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发表时间：
2014-06-01
影响因子：
3.1
通讯作者：
Taylor, C. W.
中科院分区：
文献类型：
--
作者：
Farrell, N. J. C.;Healy, D.;Taylor, C. W.
断层岩渗透率的研究有助于理解断层周围流体的运移模式，并有助于预测断层的稳定性。在这项研究中，提出了一个新的模型相结合的脆性变形结构形成的断裂过程中，流体流动通过孔隙。它评估了断层对多孔砂岩渗透率各向异性的影响，假设断层相关的微尺度变形结构的形成将改变寄主岩石的孔隙度组织，并创造新的渗透率通道。在正断层周围对岩心塞和薄片进行取样，并相对于断层面进行定向。渗透率的各向异性确定在三个方向的断层面在环境压力和围压。结果表明，平行于断层倾角测得的渗透率比沿着断层走向测得的渗透率高10倍。相应的薄片分析表明，细长孔的方向与最大主古应力（σ（1））成低角度，并平行于断层倾角，表明渗透率各向异性是由与断层相关的颗粒尺度变形机制产生的。利用土壤力学的“空细胞模型”，这项研究表明，如何细长孔可以产生在断层多孔砂岩压实和重组的颗粒通过剪切和碎裂。(c)2014作者爱思唯尔有限公司出版
Studies of fault rock permeabilities advance the understanding of fluid migration patterns around faults and contribute to predictions of fault stability. In this study a new model is proposed combining brittle deformation structures formed during faulting, with fluid flow through pores. It assesses the impact of faulting on the permeability anisotropy of porous sandstone, hypothesising that the formation of fault related micro-scale deformation structures will alter the host rock porosity organisation and create new permeability pathways. Core plugs and thin sections were sampled around a normal fault and oriented with respect to the fault plane. Anisotropy of permeability was determined in three orientations to the fault plane at ambient and confining pressures. Results show that permeabilities measured parallel to fault dip were up to 10 times higher than along fault strike permeability. Analysis of corresponding thin sections shows elongate pores oriented at a low angle to the maximum principal palaeo-stress (sigma(1)) and parallel to fault dip, indicating that permeability anisotropy is produced by grain scale deformation mechanisms associated with faulting. Using a soil mechanics 'void cell model' this study shows how elongate pores could be produced in faulted porous sandstone by compaction and reorganisation of grains through shearing and cataclasis. (c) 2014 The Authors. Published by Elsevier Ltd.