As the severity of sour drilling applications has increased the need for drill stem materials resistant to Sulfide Stress Cracking (SSC) has accelerated. This is especially true in the Middle East with some of the most severe H2S environments in the world. Sour service drillpipe, built with SSC resistant tubes and tool joints, has been available for some time. The friction welds joining the tubes and tool joints were not SSC resistant. This has been acceptable for many sour applications since the weld is not the high stress area of the drillpipe and because the operator has some control over the environment through the drilling fluid properties and additives. As more severe H2S environments were identified for exploration, it became apparent that a fully SSC resistant drillpipe system including the friction welds was necessary. This paper presents the successful development of SSC resistant friction welds for critical sour applications. It describes the engineering and manufacturing philosophy, laboratory testing procedures and results and applications for the SSC resistant drillpipe. Since NACE MR-0175 does not cover friction welds the engineering team developed unique and innovative criteria and testing procedures. A new patent pending four point bending test procedure and fixture were develop that employed unpolished samples that represent the surface finish of the product in service, unlike polished samples typically used in NACE TM-0177 testing. This paper provides background information on the evolution of sour service drillpipe and reviews case histories where sour service drillpipe has been successfully used including the new pipe with SSC resistant friction welds. A preview of some vital planning considerations for an upcoming world-class ERD well in Saudi Arabia with high H2S concentrations is also included. The paper can benefit drilling engineers involved in critical sour drilling operations in the Middle East and other world regions.

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