Proceedings, TOUGH Workshop '98, Lawrence Berkeley National Laboratory, Berkeley, CA, May 4-6, 1998, p. 250 - 256

Inverse modeling of a multistep outflow experiment for determining hysteretic hydraulic properties

Stefan Finsterle1, Torben O. Sonnenborg2, and Boris Faybishenko1

1Lawrence Berkeley National Laboratory, Earth Sciences Division
University of California, Berkeley, CA 94720

2Department of Hydrodynamics and Water Resources (ISVA) Technical University of Denmark, 2800 Lyngby, Denmark

Abstract. A new, closed-form hysteretic model of the capillary pressure-saturation and relative permeability-saturation relationship has been implemented into iTOUGH2. The hysteretic capillary pressure function is based on the van Genuchten model, with a modified version of the dependent domain model of Mualem to describe the scanning curves. Hysteresis in the relative permeability relations is considered to be mainly a result of nonwetting fluid entrap- ment. The hysteresis model was used in combination with inverse modeling techniques to examine the potential of a simple drainage-imbibition experiment to determine hysteretic hydraulic properties.