Institute for Digital Materials Research

Porous reservoir rocks are explored as hydrocarbon reservoirs and used as geothermal or gas reservoirs. They contain sedimentary and structural interfaces (bounding surfaces, faults, deformation bands) and structures caused by compaction during pressure reduction within the reservoir (pressure solution, deformation bands), which influence reservoir integrity as permeability anisotropies during hydromechanical pressure change. At the same time, a two-phase flow (injected fluid vs. formation water, oil vs. formation water) passes through the rocks, whereby the relative permeabilities depend on the wetting properties of the mineralogical microstructures. The aim of the interdisciplinary project is to model the microstructural influence on two-phase flow and reservoir integrity. For this purpose, the vertical and horizontal permeabilities in porous reservoirs, which vary during fluid pressure changes, are analysed and modelled experimentally and numerically. Coupled geomechanical and hydrodynamic models are used to calculate the three-dimensional hydrodynamics of multiphase flow, taking into account the wetting properties at the grain scale, and to derive the representative volume for the reservoir scale. The results are validated against existing reservoir data and the knowledge gained on reservoir integrity is quantified. In the integrated interdisciplinary approach, grain-scale processes are applied to reservoir processes for the first time and digital rock models are created. The results will find application in the more efficient use of deep reservoirs in exploration and as energy storage.