Assessment of the impact of CO2 storage in sandstone formations by experimental studies and geochemical modeling: The case of the Mesohellenic Trough, NW Greece. (April 2018)

• Record Type: Journal Article
• Authors: Koukouzas, Nikolaos; Kypritidou, Zacharenia; Purser, Gemma; Rochelle, Christopher A.; Vasilatos, Charalampos; Tsoukalas, Nikolaos
• Is Part Of: International journal of greenhouse gas control. Volume 71(2018)
• Page Start: 116
• Page End: 132
• Publication Date: 2018-04
• Subjects: CCS -- Sequestration -- Geological storage -- CO2-brine-rock interactions PHREEQC; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2018.01.016
• Languages: English
• ISSNs: 1750-5836

Abstract

Graphical abstract: Highlights: Sandstone samples from NW Greece reacted with a sCO2 -saturated brine under representative in-situ conditions. Geochemical modeling was employed to assess the long-term geochemical reactions in the CO2 -brine-sandstone system. The system would reach an almost steady state after ∼1000 years. Those sandstone formations seem mineralogically and geochemically suitable as CO2 storage reservoirs. Abstract: Representative sandstone samples from Mesohellenic Trough (NW Greece) were selected to investigate the geochemical reactions that occur when they come in contact with CO2 under representative in-situ conditions (T = 70 °C, P = 150 bar, 6 months reaction in batch experiments). Those sandstones consisted of predominant calcite and quartz, with lesser amounts of feldspars, chlorite, ankerite, dolomite, kaolinite, montmorillonite and muscovite. After reaction with CO2, the brine became acidic and was enriched in cations as a result of mineral dissolution. Minor mineralogical changes were observed that involved: a) the dissolution of carbonate minerals and b) the incongruent dissolution of chlorite to form clays and silica. The results related to these, have been linked with geochemical modelling using the PHREEQC code. Simulation results for a 10 ka time period predicted that chlorite was expected to dissolve completely within 100 years, leading to boehmite growth and increasing the mass of dolomite. Feldspars were expected to react at a later stage in the reaction sequence. Sensitivity tests were run to access the effect of various adjustable parameters on the outcome results. The geochemical experiments and modelling lend support to the view that Pentalofos and Tsotyli sandstone formations of the Mesohellenic Trough are suitable for the long-term storage of CO2 produced in the neighbouring lignite-fired power plants, at least in terms of mineralogy and geochemistry.