From the Pore to the Laboratory Scale: Predicting Flow Behavior for Drainage and Imbibition in Heterogeneous Porous Media
Abstract
The presented work focuses on the comparison of predictions of two-phase drainage and imbibition in heterogeneous porous media to an experimentally measured hysteretic flow process, using hydraulic properties determined on the one hand on the pore scale and on the other hand on the lab scale. For that purpose, a well controlled 3-D experiment with pre-defined block heterogeneities is conducted, where neutron tomography is used to map 3-D water distribution after successive drainage and imbibition steps. The material and hydraulic properties of the two sands are first measured in the laboratory with multistep outflow/inflow experiments. Additionally, the pore structure of the sands is acquired by means of image analysis of synchrotron tomography data and the structure is used for pore-scale simulation of one- and two-phase flow with lattice Boltzmann methods. This provides two sets of material and hydraulic properties of the sands, the second one derived from the detailed pore structure. The two sets of hydraulic properties, including hysteretic capillary pressure-saturation relationships, are then used in numerical simulations of the 3-D experiment. Hysteresis in the numerical model is combined with a capillary interface condition for the treatment of material interfaces and the approximation of saturation discontinuities due to heterogeneities. We discuss possibilities as well as difficulties and limitations in the determination of hydraulic properties of materials using two conceptually different approaches (pore scale and lab scale). We then test with the numerical simulations how good can predictions be on hysteretic two-phase flow and water content in structured media, when using these state-of-the-art methods for the determination of hydraulic properties. Based on the numerical simulations, we discuss the sensitivity in the hydraulic properties determined on different scales, the influence of material interfaces in structured heterogeneities and finally the hysteretic behavior observed in the different approaches.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.H31B0843P
- Keywords:
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- 1847 Modeling;
- 1894 Instruments and techniques: modeling;
- 1895 Instruments and techniques: monitoring