Polymorphic Varieties of CaCO3 as a Product of Cement Grout Carbonization

Cement grouts used in drilling technologies applied in the geological storage of CO2 undergo intense carbonization. Carbon dioxide, which causes carbonate or acid-carbonate corrosion of a cement grout, reacts mainly with portlandite Ca(OH)2 which is, along with hydrate calcium silicate C-S-H, a main product of basic cement components’ (alite and belite) reactions with water. Calcium carbonate formed as a result of the CO2 and Ca(OH)2 reaction may occur in the three polymorphic varieties of CaCO3 - calcite, aragonite, and vaterite. This has been proven by testing on samples taken from drilling holes made to intensify the output of rock oil through the use of CO2 (Carem et al. 2006, 2007; Scherer, Huet 2009). It is probable that the vaterite is formed in the first plate and then transforms into calcite. Aragonite is usually a transitional phase (Kurdowski 2010).