Events

Faculty Candidate Dr. Alireza Iranshahr, Reservoir Simulation Engineer at Streamsim Technologies, will present a talk entitled "Tie-Simplex Method for Thermal-Compositional Simulation" as part of the Claude R. Hocott Lectureship Series.

Abstract:  Enhanced Oil Recovery (EOR) processes usually involve complex phase behaviors between the injected fluid (e.g., steam, hydrocarbon gas, CO2) and the in-situ rock-fluid system. Equation-of-State (EoS) computations for complex mixtures than can form three, or more, phases at equilibrium pose significant challenges. In addition, issues related to proper coupling of the thermodynamic phase-behavior with multi-component transport across multiple fluid phases must be resolved in order to model the behaviors of large-scale EOR processes accurately and efficiently. Here, we propose an EoS-based tie-simplex framework to deal with the thermodynamic phase behavior, in which an arbitrary number of phases can form. It is shown that our generalized negative-flash method yields the unique tie-simplex parameterization of the compositional space. Specifically, we show that the tie-simplexes change continuously as a function of temperature, pressure, and composition. In the course of a thermal-compositional simulation, the compositional space is tabulated adaptively using tie-simplexes. We also prove that the Gibbs free-energy analysis of this tie-simplex space is equivalent to conventional methods for equilibrium phase calculations. This multiphase tie-simplex method is integrated into Stanford's General-Purpose Research Simulator (GPRS), and its application to thermal-compositional simulation is demonstrated using several challenging thermal-compositional flows with complex phase behaviors.