Methods for completing a well involve the use of computational models to design cement systems that are appropriate for the anticipated well conditions. Data from laboratory tests and/or numerical simulations may be employed in the models. The cement systems are designed to have a higher Young's modulus than the surrounding formation. In addition, the cement systems contain chemical-expansion agents that cause a microannulus to be deliberately formed at the cement/casing interface prior to the application of heat. The microannulus disappears during application of heat, pressure or both owing to casing expansion.