“…11,63 The latter entails a complex interplay between the chemical interactions of the cement with CO 2 -rich fluid, the effect this may have on its mechanical behavior, the state of stress acting on the cement in response to injection of a high-pressure fluid, and (most importantly) how all these factors affect the transport properties of the cement. Under in situ conditions, lab 63,64 and field 65,66 studies suggest that CO 2 penetration, and hence induced reaction, will be limited unless the CO 2 has a way to penetrate the cement along significant portions of the wellbore through either cracks or microannuli. If this is the case, chemical zonation by CO 2 exposure within the cement itself may affect its mechanical behavior and strength, as is also demonstrated in the present study.…”