Mechanical compaction, microstructures and permeability evolution in sandstones

We present an overview of experimental results that we obtained in the last decade on the permeability evolution with stress and the analysis of stress-induced damage in sandstones. The goal of these studies was to get a fundamental knowledge on the interplay between deformation at the microscale level, fluid flow processes and the macroscopic rock properties. In a first part we present experimental data on the effect of stress on permeability, with emphasis on the influence of stress path and failure mode. In a second part, results from a microstructural study on the mechanics of deformation in Berea sandstone are shown. Although both studies have not been done on the same rock, some general conclusions are drawn on the influence of mechanical deformation on permeability with implications for field studies. (C) 2001 Elsevier Science Ltd. All rights reserved.