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.