Modeling wells in variably saturated soil with wellbore fluid gravity segregation

A method is presented for incorporating the dynamics of a well with finite wellbore volume into finite difference models of air and water flow in vari ably saturated porous media. The method is based on the assumption of fluid gravity segregation with water accumulation at the bottom of the well. The method accurately accounts for changing water levels in the well and the c orresponding changes ill ail and water storage in the wellbore. The method was added to a three-dimensional finite difference model for multiphase Row and transport and tested against three-dimensional pilot scale experiments of water injection into initially unsaturated soil. Well water levels and soil moisture contents monitored during the course of the experiments compa red well with the model predictions. (C) 2000 Elsevier Science Ltd. All rig hts reserved.