Multiphase Non-Darcy Flow in Gas-Condensate Reservoirs

Abstract

Abstract The understanding of multiphase non-Darcy flow is important to the modeling of production from gas-condensate reservoirs. A pore-scale network model is presented here for gas-condensate flow. Porous media are modeled by networks of pore bodies interconnected by pore throats. Pore bodies and throats are characterized by their connectivity, shape, and radii distributions. Pore-level laws are identified from previously published micromodel and multiphase pipe flow experiments. The condensate can flow due to three mechanisms: pressure gradient within the sample-spanning condensate phase, movement of condensate slugs, and condensate droplets carried by the gas flow. The second mechanism appears at high capillary numbers and the third mechanism at high Reynolds numbers. Inertial terms are important for high rate gas flows. This model has been used to identify several flow regimes important to gas-condensate flow. The effect of pore structure is calculated on gas and condensate relative permeabilities in the low capillary number regime. The relative permeabilities and non-Darcy coefficients have been computed for the low condensate saturation-high pressure gradient flow regime.