Unless designed for these anticipated events, changes in temperature and pressure, mechanical shocks during drilling and completion can all create repetitive loading that can lead to stress failure of the cement sheath, which in turn can result in annular pressure buildup (also known as sustained casing pressure). Studying and testing the mechanical behavior of the cement (Young’s modulus, Poisson’s ratio, tensile strength, onset of static gel strength, etc.) under the defined wellbore conditions can significantly increase the probability of designing a zonal isolation solution that withstands the demands of completion and production.
Additionally, spacer systems can be designed to help mitigate risk. These systems can involve hollow ceramic or glass spheres that collapse to help prevent pressure build up from expansion. Or, these systems can be designed for compression with a process involving nitrification of the spacer during placement.