The in-situ permanent expansion of casing and tubing in oil and gas wells is now possible. This landmark advancement in well completion technology and repair can decrease the cost of initial well completion, make completions in difficult formations possible, and can salvage damaged completions by in-situ well repairs. The expansion of selected grades of seam welded, API casing and tubing steels has been studied with respect to its effect on the mechanical properties and resistance to
environmentally assisted cracking in sulfide containing environments. These studies demonstrated the viability of the process prior to the first successful, commercial application on November 25, 1999.