Abstract
A mathematical model to describe the heat transfer process in an oil field composed of a three-phase system is presented. The system consists of a porous medium saturated with a two-phase flow, oil and gas. Using the volume-averaging method a heat transfer one-equation model is derived. The principle of local thermal equilibrium was imposed in order to develop a one-equation model for heat transfer process in the three-phase system. The average one-equation model derived contains terms representing the convection, conduction, compressibility, and source term in addition to a term representing the exchange with the surrounding region for transient process.