Interfacial Mass Equations for In Situ Combustion

摘要

The multiphase flow of oil, water, and gas through porous media is presented when the in situ combustion technique is applied in oil reservoirs. This technique implies phenomena such as phase change, chemical reactions, and heat transfer among the phases, at their interfaces and common lines. The mathematical modeling of such a technique requires the deduction of mass, momentum, and energy equations taking into account the phenomena mentioned. In this work, the interfacial mass transport equations averaged in volume for gas (g), oil (o), and water (w) flowing simultaneously through a homogeneous, isotropic, rigid, and nonpermeable porous media (s) were obtained. The averaged interfacial mass transport equation for the deposited coke (c) on the porous media, was also obtained. To obtain the averaged equations, the local interfacial mass equations as well as their corresponding jump conditions, were used as starting point. For the interfacial region the following were taken into account: (1) the gas compressibility, (2) the mass generation of coke due to the chemical reaction of oil, (3) the mass generation of gas due to the combustion reaction between coke and oxygen, and (4) the mass transfer due to the phase change of oil and water. The closure and constitutive equations for oil and water phase change on the interfaces and common lines and an interfacial mass generation term for the deposition of coke were proposed.