Effect of Flow Configuration on the Relative Permeabilities of Water and Steam in Two Phase Flow in Geothermal Reservoirs

Abstract

In geothermal reservoirs water and steam can flow simultaneously through the porous and permeable medium which the reservoirs consist of. Darcy’s Law is the traditional relation used to describe flow through the reservoir, where the concept of relative permeability is used for multiphase flow. In this paper we assess the effects of both the initial condition of the fluid and of its flow direction on the relative permeabilities for a steady, one dimensional two phase flow of water and steam. The results show that for different types of relative permeability relations these conditions can have a significant effect. Even when the mass fractions and conditions are identical for horizontal and vertical flow, the water saturation and consequently the relative permeabilities can vary significantly with flow direction and initial condition of the fluid. It is of great importance to perform further research in this field since there may be a discrepancy between the relations commonly used and actual flow behavior. This paper also describes a large scale experiment being performed in a laboratory in Iceland. The anticipated outcome of this experiment, combined with model calculations, is improved flow relations that can be used in more advanced modeling tools.