Review of hydrogen-assisted cracking models for application to service lifetime prediction and challenges in the oil and gas industry

The present manuscript reviews state-of-the art models of hydrogen-assisted cracking (HAC) with potential for application to remaining life prediction of oil and gas components susceptible to various forms of hydrogen embrittlement (HE), namely, hydrogen-induced cracking (HIC), sulfide stress cracking (SSC), and HE-controlled stress corrosion cracking (SCC). Existing continuum models are compared in terms of their ability to predict the threshold stress intensity factor and crack growth rate accounting for the complex couplings between hydrogen transport and accumulation at the fracture process zone, local embrittlement, and subsequent fracture. Emerging multiscale approaches are also discussed, and studies relative to HE in metals and especially steels are presented. Finally, the challenges that hinder the application of existing models to component integrity assessment and remaining life prediction are discussed with respect to identification of model parameters and limitations of the fracture similitude, which paves the way to new directions for further research.