Browsing by Author "FEIZABADI, SEYED ALI"

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    An Equation-of-State Based Mathematical Modeling of Four-Phase Flow in Porous Media
    (2013-04-30) FEIZABADI, SEYED ALI; Abedi, Jalal; Chen, Zhangxing (John)
    Nowadays, oil and gas field development requires more comprehensive and precise simulations using geological, physical and chemical models than before. In fact, reservoir simulation has become an increasingly widespread and important tool for analyzing and optimizing oil recovery projects and reducing risks in development decisions. As energy demand increases and conventional hydrocarbon resources and reserves decline, new complicated recovery methods emerge such as solvent injection. Solvent injection is a method with the purpose of the viscosity reduction of heavy oil and bitumen. In this method, solvent (like propane, CO2, etc) is injected into the reservoir and diluted oil is produced. Application of this method may lead to the presence of four-phase flow in the reservoir, as it has been acknowledged in numerous papers available in the literature on oil recovery by solvent injection. In the past thirty years, the development of compositional reservoir simulators using various equations of state (EOS) has been addressed by many researchers. However, the development of compositional simulators that can handle more than two hydrocarbon phases in conjunction with EOS formulation has been particularly ignored or received very little attention. In the solvent injection simulation, the condensed solvent is a hydrocarbon; therefore, it is usually included in the oil phase. This is problematic because the simulator uses mixture properties for the oil phase within a grid whereas in reality, there are cases where the solvent-rich liquid phase and the diluted oil occupy separate spaces within the pores. It would be more accurate and align with physical reality to have another phase in the simulator for the solvent-rich liquid. Considering such a fourth phase in the simulation would allow us to track and monitor the behavior of solvent in the system accurately and make it possible to manage the recycle of the solvent in the operation similar to water in SAGD. The oil relative permeability would need to be portioned between the diluted oil (L1) phase and the solvent-rich liquid phase (L2) so that there are relative permeabilities for each of the oil phases (four-phase relative permeability). In addition, there needs to be diffusion of components in these two liquid phases into each other at the pore scale within a grid (this would be an analytical or empirical based calculation). After the properties of the two liquid phases become similar, it might be possible to combine them. This dissertation can be divided into two major parts of phase equilibrium and fluid flow in porous media. The results from phase equilibrium modeling have been implemented into the part of the fluid flow in porous media and this modeling has been extended up to four phases in equilibrium. The IMPES (implicit pressure and explicit saturations) approach has been used to solve the system of equations. Results of this modeling show that the second liquid phase forms in a certain range of pressure, temperature and composition. It has been found that the effect of this second liquid phase is considerable on the oil (L1) production.