Article ID Journal Published Year Pages File Type
4733019 Journal of Structural Geology 2015 21 Pages PDF
Abstract

•Permeability data synthesis of cataclastic bands formed in porous sandstones.•Permeability decrease is as a function of grain crushing intensity.•Major influence of normal-fault regime and moderate burial depth (1–3 km).•High porosity can slightly amplify the permeability reductions in the bands.•Coarse-grain size and good sorting can also slightly amplify these reductions.

Improving the prediction of sub-seismic structures and their petrophysical properties is essential for realistic characterization of deformed sandstone reservoirs. In the present paper, we describe permeability contrasts induced by cataclastic deformation bands and faults in porous sandstones (766 data synthesized from field examples and the literature). We also discuss the influence of several factors, including tectonic regime, presence of a fault, burial depth, host sandstone porosity, and grain size and sorting for their initiation and permeability. This analysis confirms that permeability decrease is as a function of grain-crushing intensity in bands. Permeability reduction ranges from very limited in crush-microbreccia of compaction bands to high permeability reduction in cataclasites and ultracataclasites of shear-dominated bands, band clusters and faults. Tectonic regime, and especially normal-fault regime, with its tendency to localize strain and generate faults, is identified as the most important factor, leading to the formation of cataclastic bands with high permeability contrasts. Moreover, moderate burial depth (1–3 km) favors cataclastic bands with high permeability contrasts with respect to the host sandstone. High porosity, coarse-grain size and good grain sorting can slightly amplify the permeability reductions recorded in bands.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Geology
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