Wellbore cement alteration during decades of abandonment and following CO2 attack – A geochemical modelling study in the area of potential CO2 reservoirs in the Pannonian Basin

Storage Integrity during Underground Hydrogen Storage in Depleted Gas Reservoirs

“…The impact of chemical degradation depends on the chemical reactions such as corrosion, leaching and strength reduction of cement compounds. In general, the Portland cement clinker consists of four basic mineralogical compounds, namely alite or hatrurite (3CaO • SiO2), belite or larnite (2CaO • SiO2), celite or aluminate (3CaO • Al2O3) and brownmillerite or ferrite (4CaO • Al2O3 • Fe2O3), with slight amounts of anhydrite and other component [150,151]. By adjusting the percentage of each component, Portland cement usually contains five different classes, namely Class A, B, C, D/E and G/H, where Class G/H is most commonly used in the industry.…”

Basalt powder as a supplementary cementitious material in cement paste for CCS wells: chemical and mechanical resistance of cement formulations for CO2 geological storage sites

“…Among materials used in the wellbore construction, cement has been receiving special attention from the academic community and Oil & Gas companies, since its components are not stable in CO 2 -rich environments (Teodoriu and Bello, 2020;Wang et al, 2017). From laboratory scale studies to field sampling, it is widely documented that cement is susceptible to significant changes when exposed to supercritical CO 2 , so compromising the wellbore integrity and the permanent carbon storage (Abid et al, 2020(Abid et al, , 2018Carey et al, 2007;Szabó-Krausz et al, 2020;Teodoriu and Bello, 2020).…”

“…Among the most common strategies for changing cement properties is the use of SCM in paste formulations, which alter the composition of the cement minerals, its porous structure, and the material's chemical and mechanical resistance (Abid et al, 2020;Ghafari et al, 2016;Ledesma et al, 2020;Lothenbach et al, 2011;Paris et al, 2016;Tiong et al, 2019;Yin et al, 2018). These novel formulations must be studied under appropriate conditions, similar to those found in the CCS storage site, in order to assess the extent of the CO 2 degradation process and guarantee the wellbore integrity throughout its life cycle, thereby avoiding or delaying the need for workover operations (Abid et al, 2020;Costa et al, 2019;Dong et al, 2020;Szabó-Krausz et al, 2020;Teodoriu and Bello, 2020).…”