J-R Curve Testing of OCTG Materials in Underground Storage Environments

Abstract Hydrogen has the potential to become an important energy vector in the transition towards a carbon-free energy matrix. A gradual increase in the use of hydrogen gas as a source of clean energy is considered necessary to achieve a positive transition while maintaining energy sufficiency and security. Underground Gas Storage (UGS) in depleted gas fields presents an opportunity for conversion to H2-UGS, but at the same time, it presents a higher degree of complexity in terms of material requirements. It is known that high pressure gaseous H2 have detrimental effects on fracture toughness of Oil Country Tubular Goods (OCTG) materials, and its effects need to be evaluated. In addition, it is still uncertain the interaction between H2 and underground environments and the effect of them on the material fracture toughness. J-resistance (J-R) curve testing from Compact Specimen (CT) following ASTM E1820 has emerged as one of the most suitable tests for the determination of fracture toughness of steels working in gaseous hydrogen environments. In the present study, J-R tests were performed on different OCTG grades in 200 bar of pure Hydrogen and in air. To explore the possible effect of wet condition and CO2 presence, exploratory tests were performed in environments composed of H2+Brine and H2+CO2+Brine.