Patent ID: 8392158

Claim:
A method for designing a cement system for a well having a borehole penetrating a subterranean formation, at least one casing string and at least one cement sheath, the method comprising: i. determining the mechanical properties of formations surrounding the well; ii. selecting a candidate cement system such that the cement sheath features a known amount of chemical expansion after setting, and a higher Young's modulus than the surrounding formation; iii. inputting data comprising well geometry and casing geometry into a computerized simulator; iv. running said computerized simulator to determine the cement-sheath integrity during the application of heat, pressure or both inside the well; v. if the simulation indicates cement-sheath failure, modifying the candidate cement system to adjust chemical expansion after setting, and repeating step iv; and vi. if no failure is indicated at the casing-cement interface, selecting the design as a final design.