To inject CO2 in geological formations, deep wells that penetrate the formations need to be constructed. The seal integrity of deep wells for CO2 leakage are enhanced by annulus cements. By injecting CO2, brine in formations can be carbonated and the potential degradation of annulus cement in the carbonated brine has been brought up. In this paper, Type G oil well cement (OWC) pastes are hydrated for 28 days. Conditions of geosequestration in a sandstone formation at a depth of roughly 1 km, was simulated by bubbling CO2 into a heated vessel containing brine. The hydrated OWC cylindrical specimens were exposed to this environment. Slices of the cement specimen were taken periodically, during and after exposure to quantify degradation progression. The elastic modulus of the specimens was examined prior to and after exposure. After 28 days of exposure, the degraded depth of specimen was measured as 4.137 mm. The elastic modulus of the specimens was measured as 2.2 GPa and 3.2 GPa prior to and after exposure respectively. Considering a composite action in the partially degraded specimen, the elastic modulus of degraded part can be extracted. The results indicated that the difference of elastic modulus in the partially degraded annulus cements could occur a composite action of deep wells subject to axial load and shear cracks would be generated due to the composite action.

ABSTRACT
 1. 서 론
 2. 실험방법
 3. 실험결과 및 토의
 4. 결론
 참고 문헌

• 김정중(경남대학교 건축학부) | Kim Jung Joong