Estimation of pseudo-relative permeability curves through an analytical approach for steam assisted gravity drainage (SAGD) and solvent aided-steam assisted gravity drainage

Abstract

Fluid flow through the reservoir is defined on the basis of the relative permeability which essentially captures the preferential flow of any specific fluid. Utilization of steam assisted gravity drainage (SAGD) presents challenges to the conventional understanding of relative permeability due to the introduction of heat to the reservoir. The presence of three distinct fluid phases (steam, water, and oil) in conjunction with a temperature dependency has many implications for the modelling of complex fluid dynamics. However, effective characterization of relative permeability curves is integral to successful simulation and so a model capable of representing three-phase flow is required. By implementing a simplified fractional flow analysis, this study is able to regress three-phase flow in the laboratory to a pseudo two-phase relative permeability. Modifications of conventional fractional flow theory allow for the extension of the analysis to the SAGD and solvent aided-SAGD (S-SAGD) process. Overall displacement is defined on the basis of both a microscopic component represented by modified capillary number and a macroscopic component represented by mobility ratio. Negation of the liquid-gas interaction through the assumption of waterflooding enables the generation of pseudo two-phase relative permeability curves that result in comparable performance to lab scale experiments. Because the experimentally obtained SAGD and S-SAGD results are used to construct the pseudo-relative permeability curves, our model includes the many complex fundamental changes occur in viscosity and relative permeability during SAGD and S-SAGD in the newly constructed relative permeability curves. Thus, our results offer a simplistic way to ease the compositional simulation of SAGD and S-SAGD through waterflooding approach.