Mechanisms for permeability modification in the damage zone of a normal fault,northern Perth Basin,Western Australia |
| |
| Institution: | 1. Department of Applied Geology, Curtin University, GPO Box U1987, Perth, WA 6845, Australia;2. Department of Applied Mathematics, Australian National University, Canberra, ACT 0200, Australia;1. Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK;2. Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain;3. INEUROPA, Instituto de Neurociencias del Principado de Asturias, Spain;4. Laboratorio de Metodología, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain;1. Department of Earth Sciences, Sapienza University of Rome, Italy;1. University of Western Australia, School of Earth Sciences, Centre for Exploration Targeting, ARC Centre of Excellence for Core to Crust Fluid Systems, Australia;2. School of Earth, Atmosphere, and Environment, Monash University, Melbourne, Victoria, 3800, Australia;3. Earth Science and Resource Engineering, Commonwealth Scientific and Industrial Research Organization (CSIRO), Kensington, Perth, WA 6151, Australia;1. Department of Earth Science, University of Bergen, Allegaten 41, 5007 Bergen, Norway;2. Ocean and Earth Sciences, University of Southampton, Southampton, SO14 3ZH, UK |
| |
| Abstract: | Faults and their associated damage zones in sedimentary basins can be sealing, impeding fluid flow and creating permeability barriers, or open, creating fluid pathways. This impacts the reservoir potential of rocks in fault damage zones. Stylolitization and fracturing severely impacted permeability through compartmentalization and cementation of Apium-1, an exploration hole drilled in the northern Perth Basin, Western Australia. Apium-1 is located 1 km into the hanging wall block damage zone of a major NNW-trending normal fault. The drill core consists of fine- to medium-grained quartz arenite overlain by a coarse-grained lag and capped by impermeable shale. It was quantitatively characterized by sedimentary and structural logging, and microstructural and porosity-permeability analysis. Fractures and stylolites in the damage zone of the major fault are shown to have been sealed. Extensional cracks have been sealed by quartz precipitation; shear fractures that locally preserve brecciation are always quartz and siderite cemented; stylolites are common and contain halos of quartz cementation. In each case, porosity was reduced to approximately 1%, with concomitant reduction of permeability to <<0.01 mD. These structures are observed to be interconnected in the core and are likely to form a larger-scale 3D network of steeply-dipping fractures and shallowly-dipping stylolites. The bulk permeability of the damage zone would reflect the permeability of the fractures and stylolites, compartmentalizing the Mesozoic rocks in the northern Perth Basin into elongate NW-SE trending blocks if the magnitude of stress does not exceed the cemented rock strength. |
| |
| Keywords: | Fault zone Fault damage Stylolites Sandstone |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
