Injection of CO2-saturated brine in geological reservoir: A way to enhanced storage safety
(English)Manuscript (preprint) (Other academic)
Injection of free phase supercritical CO2 into deep geological reservoirs is associated with risk of considerable return flows towards the land surface due to the buoyancy of CO2, which is lighter than the resident brine in the reservoir. Such upward movements can be avoided if CO2 is injected in the dissolved phase (CO2aq). In this work, injection of CO2-saturated brine in a subsurface carbonate reservoir is modelled. Physical and geochemical interactions of injected low-pH CO2-saturated brine with the carbonate minerals (calcite, dolomite and siderite) are investigated in the reactive transport modelling. CO2-saturated brine, being low in pH, shows high reactivity with the reservoir minerals, resulting in a significant mineral dissolution and CO2 conversion in reactions. Over the injection period of 10 years, up to 16% of the injected CO2 is found consumed in geochemical reactions. Sorption included in the transport analysis resulted in additional quantities of CO2 mass stored. However, for the considered carbonate minerals, the consumption of injected CO2aq is found mainly in the form of ionic trapping.
Injection of CO2-saturated brine, geological storage, carbonate reservoir, carbonate mineral reactions, ionic trapping, enhanced storage safety
Mineral and Mine Engineering
Research subject Applied and Computational Mathematics; Chemical Engineering; Chemistry; Civil and Architectural Engineering; Land and Water Resources Engineering
IdentifiersURN: urn:nbn:se:kth:diva-184624OAI: oai:DiVA.org:kth-184624DiVA: diva2:916395
This manuscript was submitted to the journal of International Journal of Greenhouse gas Control. The main funder for this study has been “Higher Education Commission (HEC) of Pakistan”. The study was also partly supported by Lars Erik Lundberg Scholarship Foundation, Sweden.2016-04-012016-04-012016-04-04Bibliographically approved