Evolution of the Solute Plume Composition at the Glenhaven Site (Queensland)
The site-specific geological characterisation, the prediction of CO2 plume migration and changes in physical-chemical conditions under CO2 storage conditions are important elements during the exploration and appraisal of prospective CO2 storage reservoirs.
EVOLUTION OF THE SOLUTE PLUME COMPOSITION AT THE GLENHAVEN SITE (QUEENSLAND)
Nicolas Spycher (Lawrence Berkeley National Laboratory, USA), Ralf R. Haese
The site-specific geological characterisation, the prediction of CO2 plume migration and changes in physical-chemical conditions under CO2 storage conditions are important elements during the exploration and appraisal of prospective CO2 storage reservoirs. The formation water composition, the gas composition of the injectate and lithologies can vary significantly within reservoirs. Consequently, changes in the formation water composition as a reflection of reactions between the injectate and formation water and the gas-enriched formation water and minerals will be dynamic in space and time. For example, minor concentrations of SO2 can be present in the injectate and will lead to sulfuric acid formation as it dissolves into formation water in the presence of (minor concentrations of) O2. The additional acid, however, can be buffered through the dissolution of carbonate minerals.
This project will assess the chemical evolution of formation water using two complementary approaches: Firstly, the speciation of formation water following the dissolution of the injectate gas will be calculated and reaction path modelling will be carried out to identify the most relevant fluid-mineral reactions and trends in the formation water evolution for a range of conditions (mainly variations in mineral reactive surface area and injectate gas compositions). Secondly, a 2-dimensional reaction-transport model will be developed for selected transects using the ToughReact software with input from the reaction path modelling in order to observe the extent and concentration changes within the water plume affected by the mixing and reactions with the injectate gas and reservoir minerals.
The targeted CO2 storage reservoir is the Precipice Sandstone and its overlying regional seal, the Evergreen Formation, at CTSCo’s Glenhaven site (eastern Surat Basin). The modelling will be based on an up-to-date geological model of the region and well-constrained formation water and injection gas compositions.