The impact of cementation on permeability and strength of porous limestone

Abstract

We studied mechanical compaction, strain localization and permeability in Leitha limestone. This carbonate from the area of Vienna (Austria) occurs with a broad range of grain sizes and porosity, due to changes in depositional regime and degree of cementation. Our new mechanical data revealed a simple relation between porosity and mechanical strength. Increasing cementation and decreasing porosity led to a significant increase of the rock strength both in the brittle and ductile regimes. Micromechanical modelling showed that the dominant micromechanisms of inelastic deformation in Leitha limestone are pore-emanated microcracking in the brittle regime, and grain crushing and cataclastic pore collapse in the ductile regime. Microstructural analysis revealed the development of compaction bands in some of the less cemented samples, while more cemented end-members failed by cataclastic flow in the compactant regime. In contrast to mechanical strength, permeability of Leitha limestone was not significantly impacted by increasing cementation and decreasing porosity.