Stress Corrosion Cracking Resistance of Metallic Materials used in Drilling Technology – Part 1: Test Results from Stainless Steels and UNS N07718 in Simulated Drilling Environments

Paper ID: C2025-00245 ABSTRACT: Structural materials in drilling tools are subjected to high mechanical loads while in permanent contact with the drilling fluid, which can become a corrosive environment. The simultaneous combination of tensile stresses and a corrosive environment might lead to stress corrosion cracking (SCC), which is one of the most common failure mechanisms of drillstring components. Therefore, a good understanding of the SCC susceptibility of metallic materials used in downhole components is crucial from the reliability point of view. To assess the SCC behavior of structural materials investigations were conducted considering a broad range of testing environments representing real operational conditions. Two materials including one austenitic CrMn-stainless steel and the Ni-alloy 718 (UNS N07718) have been investigated using constant load tests. The influence of pH in the range between 6 to 10, of temperature in the range between 22 to 150 °C, and of chloride concentration in the range between 17,713 to 141,812 mg/l on the SCC susceptibility of these materials was studied. Experimental results have shown that SCC susceptibility of these materials is strongly driven by temperature and oxygen content.