Modeling kinetic interface-sensitive (KIS) tracers for the optimization of supercritical carbon dioxide injection into deep saline aquifers

Alexandru Tatomir
Department of Applied Geology, Geoscience Centre of the University of Göttingen-Germany
Wednesday 24th June 2015
Aula Seminari III Piano Dipartimento di Matematica - Politecnico di Milano
Tracer methods represent techniques commonly used for the characterization and for the monitoring of transport processes in geo-reservoirs (e.g., CO2 storage, geothermal systems, oil recovery, etc.). Our current research efforts focus on the development of a new class of reactive tracers, i.e. KIS tracers useful for the characterization of fluid-fluid interfacial areas during supercritical CO2 injection into deep saline aquifers. The amount of fluid-fluid interfacial areas is important for the quantification of reactions at the fluid interface, which can implicitly lead to optimized injection strategies, a better assessment of the extent of the CO2 plume and of the storage efficiency. The work involves multi-disciplinary collaboration including laboratory experiments, synthesis of new tracer compounds and numerical modelling at pore- and continuum-scale. The presentation focuses on the development of a conceptual, mathematical and numerical model for the KIS tracers in porous media. The presented modeling approach overcomes the drawback of the current standard multiphase multicomponent models, which ignore kinetics of mass transfer over the interfacial area between the CO2 and brine and consider only the volumetric fraction of the fluids or their mass and molar fractions, respectively. In this model, the concept of a specific interfacial area obtained from pore network modeling is used to complement the constitutive relationships between capillary pressure and saturation. It is a two-phase four component flow and transport model with a kinetic mass transfer of tracers between the two fluids and taking the dissolution of CO2 in brine into account. The modeling approach uses parameters obtained from experimental lab work. Their implications are investigated by sensitivity analyses to narrow the physical range of reaction rates for further experiments and molecular tracer design. contact: