Chapter 5. Production Riser Life Extension – A Class Perspective Available to Purchase

Risers are a critical element in subsea production systems for transporting hydrocarbons from the seafloor to the surface. Many subsea production risers are approaching the end of their original design life (e.g. 20 or 25 years); therefore, they need to be either decommissioned or entered into in a life extension process. Due to enhanced recovery and tiebacks from adjacent fields, more and more existing fields are continuing to produce. As a result, the life extension of those offshore assets including production risers has become a viable solution.

For a riser’s life extension application, the process generally includes three phases: investigation, determination, and implementation. Baseline surveys and data collection should be performed during the investigation phase. A riser’s life extension requires a life extension assessment created from collected riser characteristic data, condition data, and operating data to confirm the riser’s integrity and its capacity for extended operations under future operating conditions. The life extension assessment may confirm that the riser is fit-for-service in its present condition for the planned extended service life, or call for a plan with repairs, component replacements, additional inspections, additional monitoring, or a combination of these.

An application for riser life extension is usually required to be submitted to the local Authority (if applicable) for approval. Owners and operators generally require the review of the riser life extension by an independent third party (I3P). The earlier the I3P/CVA engages in the process, the better the readiness of the life extension application.

Currently, industry experience on production riser life extension is limited, and safety of aging production risers is a major focus of the industry. This paper addresses the technical recommendations and guidance from a Class perspective on life extension for subsea production risers attached to floating production installations that produce and/or store hydrocarbons. The same process and methodology are also applicable to injection risers and import/export risers. The technological challenges associated with riser life extensions are highlighted. Special cases of the riser life extension in Gulf of Mexico (GoM) and risers managed in an integrity management program are also demonstrated.