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Various geoscientific applications require a fastprediction of fracture permeability for an optimal workflow. Hence, theobjective of the current study is to introduce and validate a practicalmethod to characterize and approximate single flow in fractures underdifferent stress conditions by using a core-flooding apparatus, in situX-ray computed tomography (CT) scans and a finite-volume method solving theNavier–Stokes–Brinkman equations. The permeability of the fracturedsandstone sample was measured stepwise during a loading–unloading cycle (0.7 to 22.1 MPa and back) to validate the numerical results. Simultaneously,the pressurized core sample was imaged with a medical X-ray CT scanner witha voxel dimension of 0.5  ×  0.5  ×  1.0 mm3. Fracture geometries were obtained by CT images based on a modification ofthe simplified missing attenuation (MSMA) approach. Simulation resultsrevealed both qualitative plausibility and a quantitative approximation ofthe experimentally derived permeabilities. The qualitative results indicateflow channeling along several preferential flow paths with less pronouncedtortuosity. Significant changes in permeability can be assigned to temporaland permanent changes within the fracture due to applied stresses. Thedeviations of the quantitative results appear to be mainly caused by bothlocal underestimation of hydraulic properties due to compositional matrixheterogeneities and the low CT resolution affecting the accurate capturingof sub-grid-scale features. Both affect the proper reproduction of theactual connectivity and therefore also the depiction of the expectedpermeability hysteresis. Furthermore, the threshold value CTmat (1862.6 HU) depicting the matrix material represents the most sensitive inputparameter of the simulations. Small variations of CTmat can causeenormous changes in simulated permeability by up to a factor of 2.6 ± 0.1 and, thus, have to be defined with caution. Nevertheless, comparison withfurther CT-based flow simulations indicates that the proposed methodrepresents a valuable method to approximate actual permeabilities,particularly for smooth fractures (< 35 µm). However, furthersystematic investigations concerning the applicability of the method areessential for future studies. Thus, some recommendations are compiled byalso including suggestions of comparable studies

Simulating stress-dependent fluid flow in a fractured core sample using real-time X-ray CT data