Anisotropic pore fabrics in faulted porous sandstones
Anisotropic pore fabrics in faulted porous sandstones
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DOI：
10.1016/j.jsg.2017.09.010
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发表时间：
2017-11-01
影响因子：
3.1
通讯作者：
Healy, D.
中科院分区：
文献类型：
--
作者：
Farrell, N. J. C.;Healy, D.
断层带周围沉积岩的孔隙组构可能会发生显著的变化。了解孔隙组构在断层作用期间和之后如何变化，对于了解岩石如何在断层带周围传输流体非常重要，并且可以帮助预测由于孔隙流体压力变化而导致的机械不稳定性。缺乏详细描述断层多孔岩石中孔隙结构几何形状的数据集。本文描述了从两个出露的正断层砂岩中量化的孔隙组构。从岩心塞和薄片中量化孔隙度和孔隙的大小、形状和几何形状。结果被映射在一个框架内的故障，以更好地说明如何使用这些数据集，以提高对断层带周围的流体流动的理解。来自成熟的富石英砂岩的结果显示孔隙组构的变化，从水平取向且平行于叠层的孔隙到与sigma（1）成低角度取向的孔隙。孔隙织物量化从粘土丰富，石英次长石砂岩从中等纵横比孔没有优先方向，高纵横比孔定向占主导地位的子平行于断层面的变化。在相应的岩心塞上测得的渗透率显示出渗透率的各向异性，最大渗透率沿两个断层的断层倾角向下。(C)2017作者出版社：Elsevier Ltd
The fabric of pores in sedimentary rocks around fault zones can be subject to significant modification. Knowledge of how pore fabrics vary during and after faulting is important for understanding how rocks transmit fluids around fault zones, and can help to predict mechanical instability due to changes in pore fluid pressure. Datasets detailing the geometry of pore fabrics in faulted porous rocks are lacking. This paper describes pore fabrics quantified from two outcrops of normally faulted sandstone. The porosity and the size, shape and geometry of pores were quantified from core plugs and thin sections. Results were mapped within a framework of the faults to better illustrate how these datasets may be used to improve understanding of fluid flow around fault zones. Results from a mature, quartz-rich arenite show a change in pore fabric from pores oriented horizontally and parallel to laminations to pores oriented at a low angle to sigma(1). Pore fabrics quantified from a clay-rich, quartz sub-arkose changed from moderate aspect ratio pores with no preferred orientation, to high aspect ratio pores oriented dominantly sub parallel to the fault surface. Permeabilities measured on corresponding core plugs showed anisotropy of permeability with maximum permeability oriented down fault dip around both faults. (C) 2017 The Authors. Published by Elsevier Ltd.