TY - JOUR
T1 - In-Situ X-ray Tomography Study of Cement Exposed to CO2 Saturated Brine
AU - Chavez Panduro, E. A.
AU - Torsæter, M.
AU - Gawel, K.
AU - Bjørge, R.
AU - Gibaud, A.
AU - Yang, Yan
AU - Bruns, S.
AU - Zheng, Yi
AU - Sørensen, H. O.
AU - Breiby, D. W.
PY - 2017
Y1 - 2017
N2 - For successful CO2 storage in underground reservoirs, the potential problem of CO2 leakage needs to be addressed. A profoundly improved understanding of the behavior of fractured cement under realistic subsurface conditions including elevated temperature, high pressure and the presence of CO2 saturated brine is required. Here, we report in situ X-ray micro computed tomography (μ-CT) studies visualizing the microstructural changes upon exposure of cured Portland cement with an artificially engineered leakage path (cavity) to CO2 saturated brine at high pressure. Carbonation of the bulk cement, self-healing of the leakage path in the cement specimen, and leaching of CaCO3 were thus directly observed. The precipitation of CaCO3, which is of key importance as a possible healing mechanism of fractured cement, was found to be enhanced in confined regions having limited access to CO2. For the first time, the growth kinetics of CaCO3 under more realistic well conditions have thus been estimated quantitatively. Combining the μ-CT observations with scanning electron microscopy resulted in a detailed understanding of the processes involved in the carbonation of cement.
AB - For successful CO2 storage in underground reservoirs, the potential problem of CO2 leakage needs to be addressed. A profoundly improved understanding of the behavior of fractured cement under realistic subsurface conditions including elevated temperature, high pressure and the presence of CO2 saturated brine is required. Here, we report in situ X-ray micro computed tomography (μ-CT) studies visualizing the microstructural changes upon exposure of cured Portland cement with an artificially engineered leakage path (cavity) to CO2 saturated brine at high pressure. Carbonation of the bulk cement, self-healing of the leakage path in the cement specimen, and leaching of CaCO3 were thus directly observed. The precipitation of CaCO3, which is of key importance as a possible healing mechanism of fractured cement, was found to be enhanced in confined regions having limited access to CO2. For the first time, the growth kinetics of CaCO3 under more realistic well conditions have thus been estimated quantitatively. Combining the μ-CT observations with scanning electron microscopy resulted in a detailed understanding of the processes involved in the carbonation of cement.
U2 - 10.1021/acs.est.6b06534
DO - 10.1021/acs.est.6b06534
M3 - Journal article
C2 - 28701043
SN - 0013-936X
VL - 51
SP - 9344
EP - 9351
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 16
ER -