This collection contains 10500 computationally generated, randomised 2D microstructures, their geometrical and electrical properties, and the Matlab software package used to calculate these properties. The two-phase microstructures (mineral matrix, pore space) represent three different pore space types (microfracture networks, intergranular pore space, oomoldic pore space) and are organised into 35 ensembles - with common modelling parameters - of 100 individual microstructure realisations each. For all realisations, several geometrical properties (percolation, total porosity, connected porosity, isolated porosity, surface area, fractal dimension) and physical properties (formation factor from electrical resistivity, electrical tortuosity) are given. The collection also includes a Matlab-based finite element simulation package derived from the FEMALY library, which can be used to compute the properties of any given 2D raster microstructure.
This dataset is supplemental to the paper Wallis et al. (2019) and contains data derived from distortion of crystal lattices measured using conventional electron backscatter diffraction (EBSD) and high-angular resolution electron backscatter diffraction (HR-EBSD). The datasets include lattice misorientation, elastic-strain heterogeneity, residual-stress heterogeneity, and densities of geometrically necessary dislocations in olivine and quartz. We intend the data and associated paper to demonstrate key aspects of the HR-EBSD technique and to draw comparisons with conventional EBSD. As the paper by Wallis et al. (2019) is a review paper, several of the datasets have also been present in, or are otherwise related to, additional previous publications listed below .
Data are provided as 55 tab delimited .txt files organised by the figure in which they appear within Wallis et al. (2019). Data types are indicated in the file names. Please consult the data description file for detailed explanations.
Hydrocarbon or groundwater production from sandstone reservoirs can result in surface subsidence and induced seismicity. Subsidence results from combined elastic and inelastic compaction of the reservoir due to a change in the effective stress state upon fluid extraction. The magnitude of elastic compaction can be accurately described using poroelasticity theory. However inelastic or time-dependent compaction is poorly constrained. We use sandstones recovered by the field operator (NAM) from the Slochteren gas reservoir (Groningen, NE Netherlands) to study the importance of elastic versus inelastic deformation processes upon simulated pore pressure depletion. We conducted conventional triaxial tests under true in-situ conditions of pressure and temperature. To investigate the effect of applied differential stress (σ1 – σ3 = 0 - 50 MPa) and initial sample porosity (φi = 12 – 25%) on instantaneous and time-dependent inelastic deformation, we imposed multiple stages of axial loading and relaxation.
The obtained data include:
1) Mechanical data obtained in conventional triaxial compression experiments performed on reservoir sandstone. In these experiments, we imposed multiple stages of active loading, each followed by 24 hours of stress relaxation.
2) Microstructural data obtained on undeformed and deformed samples.