CCUS is considered by IPCC to be a major technical solution to reducing CO2 emission and controlling CO2 concentration in the atmosphere within an acceptable level in the 21st century.
For the long term safety of CO2 storage in either saline aquifers or oil reservoirs, it requires to account for the complex geochemical reactions in the sequestration simulation. Proper modeling of the geochemical reactions is critical to understanding many associated phenomena like CO2 leakage, injectivity change, and mineral formation or dissolution.
Reactive transport modeling for underground process is traditionally conducted in geology and environmental engineering, with applications such as nuclear contamination analysis and CO2 sequestration in aquifers.
The developed geochemical simulators are capable of describing complex geochemistry with many reactions but they are usually simplistic for fluid phase equilibrium, many simulations being single fluid (aqueous) phase or two-phase at most.
The methods used in these simulators for reaction equilibrium calculation are not sufficiently efficient. On the other hand, compositional reservoir simulation in the oil industry can handle the complex phase equilibrium between hydrocarbon phases. Its weakness is in the aqueous phase description and the geochemical reactions are either missing or insufficient in most commercial simulators.
The objective of this project is to integrate multiphase reaction into compositional reservoir simulation such that the developed reservoir simulator should be able to handle both complex phase equilibrium in oil production and the geochemical reactions in the aqueous phase and with the solid minerals. The integration will be based on our recent study on simultaneous chemical and phase equilibrium modeling.
Our approach provides an efficient solution to simultaneous chemical and phase equilibrium calculation, and is particularly suitable to geochemical systems with many reactions.
In addition to equilibrium reactions, another aspect that the compositional simulator needs to account for is the kinetics of the relatively slower reactions. The developed simulator is expected to provide a general framework for multiphase reactive transport modeling of underground fluid flow in porous media.
It can be used not just for simulating CO2 sequestration and CO2 enhanced oil recovery but also for analyzing other reservoir processes where reactions are crucial, such as smart water injection and chemical tracer tests.
Main supervisor: Wei Yan
Co- supervisor: Erling H. Stenby