DOI: 10.5176/2251-3361_GEOS12.55
Authors: Thomas Millan, Eric Lécolier, Teddy Parra, Bernard Guy, Jacques Moutte
Abstract: Storing carbon dioxide underground is a potential solution for reducing CO2 emissions. However a leaking wellbore can be a pathway for CO2 migration, leading to reduction of CO2 storage efficiency. So, preventing any carbon dioxide leakage through a cemented wellbore annulus after injection is a key to ensure long-term wellbore integrity. The purpose of this study is to study the evolution of the mineralogy in cement samples exposed to CO2 fluids, and the evolution of the carbonation depth with the ageing time. The conditions of experiments are 80°C under 5 MPa during 14, 28 and 87 days. X-ray diffraction (XRD), Fourier Transform Infrared spectrometry (FTIR) and ThermoGravimetric Analysis (TGA) analysis show that the mineralogical evolution is the same for the three samples. On the other hand, the alteration thickness increases from about 2-2.5 mm for the 14 day aged sample to about 4-4.5 mm for the 87 day aged sample. The regular samplings of the ageing solution allow to determine the composition of the pore water during the experiments, and determine what are the minerals that control the aqueous solution chemistry
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