Numerical simulation and experimental investigation of reactive flow in a carbonate reservoir

Abstract

This thesis presents experimental and numerical investigations of reactive flow in carbonate reservoirs during CO2 injection for storage. The key aims are to understand how CO2-brine-rock chemical interactions could cause variations in rock properties in carbonate formations and identify the key factors controlling these variations at the core- and inter-well scales. A series of core flood experiments were conducted using outcrop samples and representative reservoir samples from a CO2 storage candidate, a depleted carbonate gas reservoir. The samples were characterized pre- and post-injection for porosity and permeability changes, and effluent concentrations temporal evolution were monitored. Reactive transport simulations of the core flood experiments were conducted, and the simulation results were compared and history-matched against the laboratory data. The experimentally validated and calibrated parameters obtained from the core-scale simulations were then used in an inter-well-scale high-resolution heterogeneous outcrop model to analyze how the introduction of additional geological heterogeneity changes the evolution of rock properties compared to the core-scale simulations and experimentation. This research has shown that combining the experiments and numerical simulations allows enhanced understanding of chemical interactions during CO2 injection in carbonate reservoir, including the controlling factors. Factors like reservoir heterogeneities, injection fluid temperature, and type of reservoir fluid at the injection interval, to a certain extent, influence the mineral reactivity. Information gathered from the core-scale experiments, and the core-scale models to develop a larger-scale model is an appropriate approach to predict mineral reactivity and its subsequent impact on reservoir properties for CO2 storage projects more accurately. A numerical model with improved accuracy enables more reliable field-scale reactive transport simulations of CO2 geological storage. Hence, it will guide the optimization of the injection/production operations and improve the design of CO2 storage processes in a real target formation.