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

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

A Unified Thermal-Reactive Compositional Simulation Framework for Modeling CO₂ Sequestration at Various Scales

In this work, we present a unified framework for the simulation of CO2 sequestration problems at various time and space scales. The parametrization technique utilizes thermodynamic state-dependent operators expressing the governing equations for the thermal-compositional-reactive system to solve the nonlinear problem. This approach provides flexibility in the assembly of the Jacobian, which allows straightforward implementation of advanced thermodynamics. We validate our simulation framework through several simulation studies including complex physical phenomena relevant to CCUS. The proposed simulation framework is validated against a set of numerical and experimental benchmark tests, demonstrating the efficiency and accuracy of the modeling framework for CCUS-related subsurface applications. Important physical phenomena resulting from the complex thermodynamic interactions of CO2 and impurities with reservoir fluids can be accurately captured now in detailed dynamic simulation. The investigated simulation scenarios include a reproduction of lab experiments at the core scale, investigation of macro-scale analog model and simulation of large-scale industrial application. The simulation time can also span from hours to years among various applications. Complex thermal-compositional-reactive phenomena can be addressed at each of these space and time scales. The unified thermodynamic description allows us to perform all these simulations for a reasonable CPU time due to advanced parametrization techniques and efficient GPU capabilities in our in-house reservoir simulator DARTS.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Reservoir Engineerin