Tubulars meeting the minimum requirements of API Specification 5CT have failed by sulfide stress cracking in sour gas production environments. Alberta's Recommended Practices for completing and producing critical sour gas wells are being revised. Significant changes have been made to the material and testing requirements to ensure that casing, tubing and couplings have sufficient resistance to sulfide stress cracking when used in critical sour gas wells. These changes include restricted chemical composition and hardness requirements, environmental crack testing, and manufacturer pre-qualification. This paper will describe the material- and testing-related requirements and acceptance criteria of these Industry Recommended Practices. Sulfide stress cracking test and other data for tubing and casing which have failed in sour gas service and for tubulars which meet the requirements of the IRPs will be provided and compared.
Keywords: H2S (hydrogen sulfide), sour gas wells, casing, tubing, sulfide stress cracking, hydrogen- induced cracking, stress-oriented hydrogen-induced cracking, acceptance criteria, recommended practices.