Data and software used in: “Non-Hertzian stress fields in simulated sandstone grains and implications for compactive brittle failure - a high-resolution FEM approach”
Globally, sandstone formations are typically targeted for hydrocarbon extraction. However, these activities often lead to surface subsidence or even induced seismicity. The cause lies in reservoir compaction driven by pore pressure depletion and the associated increase in effective overburden stress. Such compaction is partly elastic, but can additionally be caused by instantaneous plastic and rate/time-dependent processes, such as subcritical crack growth. Compaction due to grain breakage, either via critical or subcritical crack growth, is driven by tensile stresses acting on surface and volume flaws. Therefore, we performed high-resolution 3D linear elastic FEM simulations on simplified grain assemblies to investigate the effect of stress-strain boundary conditions, porosity and mineralogical variations on grain-scale stress fields. We found that compactive failure of sandstone due to grain breakage is related to the probability of pre-existing surface flaws with size up to 30 μm falling in a pore surface region with sufficiently high tensile stress where the Griffith criterion is satisfied. Using the tensile stress distribution observed in the 3D FEM simulations, a preliminary, time-independent failure probability model was developed, which qualitatively predicts a non-linear increase in grain cracking during deviatoric loading. The detailed findings of our work are found in the corresponding paper. The data presented here are the input geometry and output (results) for the 3D FEM simulations, an in-house python code for 2D FEM simulations performed to obtain polynomial functions employed to describe appropriate boundary conditions for some of the 3D simulations, the input geometry and output (results) for the 2D FEM simulations and a MATLAB script for the failure probability model.
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