Influence of damage on pore size distribution and permeability of rocks

Abstract

International audienceThe model proposed in this article relates permeability to porosity measurements that can easily be performed in the laboratory. The pore size distribution (PSD) curve is updated with strains and damage. The updated volumetric fractions of natural pores and cracks are introduced in the expression of permeability. Contrary to classical permeability models based on PSD integrations, the model proposed in this article accounts for possible changes in the porosity modes: one mode for undamaged samples and two modes for cracked samples. The proposed approach also accounts for varying states of damage, as opposed to classical fracture network models, in which the cracks pattern is fixed. The only material parameters that are required to describe the microstructure are the lower and upper bounds of the pores size for both natural pores and cracks. All the other PSD parameters involved in the model are related to macroscopic parameters that can easily be determined in the laboratory, such as the initial void ratio. The framework proposed in this article can be used in any damage constitutive model to determine the permeability of a brittle porous medium. Drained triaxial compression tests have been simulated. Before cracks initiation, permeability decreases while the larger natural pores are getting squeezed. After the occurrence of damage, permeability grows due to the increase of cracks density. The model performs well to represent the influence of the confining pressure on damage evolution and permeability variations. © 2012 John Wiley and Sons, Ltd

Back Analysis of Geomechanical Parameters of Rock Masses Based on Seepage‐Stress Coupled Analysis

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“…Depletion activities during hydrocarbon extraction may result in inelastic compaction that gives rise to ground surface subsidence, borehole instability, or triggered seismicity. Carbon sequestration, hydraulic fracturing applied to geothermal reservoirs and shale gas production, and numerous enhanced hydrocarbon recovery methods that rely on injecting fluids at elevated pressure may induce seismicity, brittle fractures, and faults , .…”

Chemomechanical evolution of pore space in carbonate microstructures upon dissolution: Linking pore geometry to bulk elasticity

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