Stress-Dependent Permeability Measurement of Indiana Limestone and Silurian Dolomite Samples in Hydrostatic Tests Available to Purchase

Permeability is an intrinsic property of porous materials, dependent of pore size and interconnection in microscopic level, as well as fissure width and orientation in macroscopic level. Mechanical loading of such a porous material leads to changes in the geometry of the pore space with impacts on the macroscopic measured permeability. Realistic reservoir simulation models should consider these permeability changes as these may affect the reservoir pressure distribution, saturation front shapes and also the drilling mudwindow of infill drilling wells. However, the petroleum industry still lack of reliable and comprehensive permeability variation models and parameters. The article presents results of a campaign of hydrostatic tests underwent on samples from limestone and dolomite outcrops. The main target of those tests is the strain-dependent permeability measurement and the validation of the model proposed by Petunin et al. (2011). This model is an extension to the Carman-Kozeny formulation and, although still simplistic by considering pore volume changes alone as the main driver for the permeability variations, it may be quite effortlessly introduced in the conventional numerical reservoir simulators as Carman-Kozeny exponents or even as cell permeability multipliers. The results presented here are the first step of an internal project which aims to determine the correlation between variation in permeability caused by variation of in situ stress and strain state due to reservoir depletion for limestone and dolomite oil reservoirs. The chosen commercial Silurian Dolomite and Indiana Limestone outcrops can be considered as quasi-homogeneous standard materials when compared to real reservoir samples, a key aspect for this testing methodology validation.