Numerical generation of stress-dependent permeability curves

In this study, we presented a numerical method to investigate the behavior of absolute permeability changes under various stress conditions using Micro-Computed Tomography (CT) images. To benchmark this method, we implemented this workflow for a Berea sandstone sample. A digital rock model is constructed using CT images and rock deformation under stress is simulated using Finite-Element Analysis. Then, absolute permeability in the deformed rock is computed using Lattice Boltzmann Methods. Since, stress analysis and LBM analyses are time-consuming processes to be implemented for any arbitrary stress conditions, we proposed utilizing the state function method to define permeability as a function of stress invariants. The outcomes of the study show that in poorly consolidated formations, permeability is a strong function of effective stress and decreases nonlinearly as the change in stress invariants becomes more significant. The presented coupled workflow shows some capabilities for predicting absolute permeability for different rock types in different directions.