Pipeline fracture control concepts for Norwegian offshore carbon capture and storage

The Northern Lights onshore terminal will initially receive CO₂ transported by ship tankers from industrial source sites located in south-eastern Norway and transport CO₂ via a 12 ¾” OD offshore pipeline for injection into the Johansen storage reservoir, located south of the Troll field. The CO₂ injection pipeline will be laid from the shore terminal to a subsea wellhead structure from where the liquid CO₂ will be injected into the reservoir. Presently, demonstrating arrest of longitudinal propagating shear fracture in CO₂ transport pipelines is specifically addressed in two international guidelines, ISO 27913 and DNVGL-RP-F104. The study reported here aims to develop a robust fracture control methodology unique to the Northern Lights pipeline. To this end, the maximum loading in terms of saturation pressure is conservatively estimated from temperature and pressure scenarios from the planned pipeline route and applied in numerical simulations of the running-fracture phenomenon using the SINTEF coupled FE-CFD code. It is shown that, with the given pipe material, diameter, and loading conditions, the proposed wall thickness of 15.9 mm is sufficient to arrest a propagating crack. Furthermore, the Battelle TCM with ISO 27913 or DNVGL-RP-F104 arrest- and load pressure correction is shown to provide a good first estimate in pipe design, although the arrest pressure saturates for low Charpy energy toughness values, indicating limited accuracy in this study