Title

Modelling of reactive flow and transport in the presence of a complex phase transition phenomena

Document Type

Conference Proceeding

Date of Original Version

1-1-2016

Abstract

We present a novel simulation approach for modeling of reactive flow and transport in multiphase multicomponent mixtures that include light gases, hydrocarbon components, and different ions present in an aqueous electrolyte phase. The phase behavior in these systems involves both thermodynamically-driven phase transitions (e.g. between supercritical vapor and liquid phases) and chemically driven precipitation and dissolution of solid (mineral) phases. All phases are modeled using the multi-scale Gibbs-Helmholtz Constrained Equation of State (GHC EoS), which up-scales molecular length scale information from a priori Monte Carlo simulations to help build accurate estimates of the energy parameter. Our proposed approach is implemented in the combined software system included the Automatic Differentiation General Purpose Research Simulator (ADGPRS) developed at Stanford University and the GFLASH library developed at University of Rhode Island. The extended variable substitution schema for a natural fully implicit formulation is designed to support the potential coexistence of an arbitrary set of phases in the flow. The classical reduction in the number of conservation equations based on element balances is combined with specific local constraints describing simultaneous thermodynamic and chemical equilibrium. Rigorous flash solutions for detecting phase changes in each grid block are computed using phase splitting and phase/chemical equilibrium to ensure equality of component chemical potentials and by monitoring the Gibbs free energy of the system to guarantee a global minimum is found. We present examples that cover a wide range of physical processes related to CO2 sequestration in saline aquifers.

Publication Title

15th European Conference on the Mathematics of Oil Recovery, ECMOR 2016

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