The Challenge
Pre-salt production carries high CO₂ content, and reinjection or transport systems face a combination that is unforgiving: dense-phase CO₂, water and H₂S impurities, high pressure and long design life. Carbon steel alone is not a credible answer where free water can form.
CO₂ pipelines also behave differently from hydrocarbon lines in ways that matter structurally — phase behaviour through depressurisation, Joule-Thomson cooling at leaks, and running ductile fracture arrest requirements that do not follow conventional gas pipeline rules.
Our Approach
With CO₂, the impurity specification is the design input. Everything downstream — corrosion, fracture control, operating philosophy — follows from it.
VORYX team members delivered engineering and qualification for CRA-lined pipelines under these conditions, starting from the impurity specification rather than the pipe. The composition envelope drives everything downstream — corrosion mechanism, liner material selection, fracture control and operating philosophy.
Material selection and qualification addressed liner alloy performance under sour and CO₂ service, hydrogen-induced stress cracking risk in the relevant alloys, and the integrity of the mechanically lined interface through installation and thermal cycling.
Long-term performance was assessed across the full operating envelope, including transient depressurisation cases and the running-fracture arrest requirement, referenced against the CO₂-specific framework in DNV-RP-F104 alongside DNV-ST-F101.
What We Delivered
- CO₂ composition and impurity envelope definition
- Material selection and CRA liner qualification for sour / CO₂ service
- Corrosion and integrity assessment under dense-phase conditions
- HISC and cracking-susceptibility evaluation for the selected alloys
- Running ductile fracture control assessment
- Transient depressurisation and phase-behaviour review
- Long-term performance and design-life justification
The Outcome
- A CO₂ pipeline concept qualified for pre-salt service conditions
- Liner material selection defensible against sour and CO₂ degradation mechanisms
- Fracture control and depressurisation behaviour addressed to CO₂-specific guidance
- Engineering basis suitable for CCUS-scale deployment
Standards Applied
- DNV-RP-F104
- DNV-ST-F101
- DNV-RP-F112
- ISO 15156 / NACE MR0175
- API 5LD
Operator and project names are anonymised for confidentiality and disclosed on request. Experience described is that of VORYX team members.
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