Researches On The Migration Of Supercritical CO₂on Geological Storage Conditions

In order to mitigate the global warming, development of the technologies forCO2storage is very necessary.CO2storage in geological formations especially in deepsaline aquifers is considered a promising way. As an important basis, the mechanisms ofsupercritical CO2and water two phase flow of in porous media is not yet fullydeveloped. Therefore, to have a better understanding of CO2migration aquifers, thisthesis investigates characteristic functions of multiphase fluid flow migration and theinfluences of formation heterogeneityand dissolution conditions by using experimentaland numerical methods.As important functions of describing multiphase displacement processes inporousmedia, relative permeability and capillary pressurecurves from different core samplesare obtained, whichprovide essential parameters for numerical modeling.This paper alsosuccessfully extended relative permeability curves by analyzing capillary pressureexperimental data. A1D modeling approach using multiphase transport code TOUGH2proposes several set of parameters allowing a good match between experiments andmodels. Sensitivities of ‘end effect’, capillary pressure, permeability, residual gas andwater are analyzed using the same model. A series of experiments are performed tostudy the influence of the CO2exsolution, calcite dissolution and precipitation. It showsthe effect on permeability due to CO2exsolution triggered by pressure drop ispredictable. Calcite precipitates in different forms depending on chemicalconditions,which has a much obvious influence on low permeability rocks than highpermeability ones by blocking the pores and/or throats.