Articles | Volume 7, issue 3
Solid Earth, 7, 727–739, 2016

Special issue: Pore-scale tomography & imaging - applications, techniques...

Solid Earth, 7, 727–739, 2016

Method article 04 May 2016

Method article | 04 May 2016

Development of a numerical workflow based on μ-CT imaging for the determination of capillary pressure–saturation-specific interfacial area relationship in 2-phase flow pore-scale porous-media systems: a case study on Heletz sandstone

Aaron Peche1,2, Matthias Halisch3, Alexandru Bogdan Tatomir2, and Martin Sauter2 Aaron Peche et al.
  • 1Leibniz-Universität Hannover, Institute of Fluid Mechanics and Environmental Physics, Appelstraße 9A, 30167 Hannover, Germany
  • 2Georg-August Universität Göttingen, Department of Applied Geology, Goldschmidtstraße 3, 37077 Göttingen, Germany
  • 3Leibniz Institute for Applied Geophysics, Department 5, Petrophysics and Borehole Geophysics, Stilleweg 2, 30655 Hannover, Germany

Abstract. In this case study, we present the implementation of a finite element method (FEM)-based numerical pore-scale model that is able to track and quantify the propagating fluid–fluid interfacial area on highly complex micro-computed tomography (μ-CT)-obtained geometries. Special focus is drawn to the relationship between reservoir-specific capillary pressure (pc), wetting phase saturation (Sw) and interfacial area (awn). The basis of this approach is high-resolution μ-CT images representing the geometrical characteristics of a georeservoir sample. The successfully validated 2-phase flow model is based on the Navier–Stokes equations, including the surface tension force, in order to consider capillary effects for the computation of flow and the phase-field method for the emulation of a sharp fluid–fluid interface.

In combination with specialized software packages, a complex high-resolution modelling domain can be obtained. A numerical workflow based on representative elementary volume (REV)-scale pore-size distributions is introduced. This workflow aims at the successive modification of model and model set-up for simulating, such as a type of 2-phase problem on asymmetric μ-CT-based model domains. The geometrical complexity is gradually increased, starting from idealized pore geometries until complex μ-CT-based pore network domains, whereas all domains represent geostatistics of the REV-scale core sample pore-size distribution. Finally, the model can be applied to a complex μ-CT-based model domain and the pcSwawn relationship can be computed.

Short summary
In this case study, we compute georeservoir specific capillary pressure-saturation- interfacial area relationships by implementing a FEM-based two-phase flow model on μ-CT-based modelling domains. We propose a recommended practice for deriving a model and model setup for the successful modelling of such types of problems on micro-CT obtained geometries.