Life extension of existing offshore structures in the Gulf of Mexico is receiving increasing attention from operators and our governing agency, BSEE.
New standalone developments in current market conditions are challenging, so many operators are considering tiebacks to existing platforms which provides a lower risk and faster return on investment. Many deepwater Gulf of Mexico platforms are now reaching their 15 to 20th year of service and tying additional wells back to them with production lives of 10-20 years will require an extension of the platform and the existing risers beyond their original design life.
At this year’s Subsea Tieback Forum in San Antonio, BSEE introduced a plan outlining their requirements for granting permits for riser life extensions in the GoM. They have started to receive life extension requests for SCRs, flexibles and TTRs and are finding that those applications are not complete enough to demonstrate the feasibility of extending the life of the riser system. As a result, BSEE will be rolling out a new requirement for riser life extension CVA (certified verification agent) or independent verification. Here is a summary of what is proposed:
What future riser life extension requests will require
- Combination of analyses and inspections
- Forward-looking integrity management plan
- Riser life extension CVA verification – THE NEW REQUIREMENT
Riser life extension CVA – a three stage process
A life extension CVA will need to incorporate verification in three stages:
Stage 1 – Initial life analysis
- Riser detailed design data, e.g. components, materials, cathodic protection, coatings/barriers, tensioners
- Historical operational data, e.g. pressure, temp, fluid chemistry, inhibitor usage.
- Historical environmental data, e.g. monitored/assumed motions, currents, sea states
- Detailed analysis
Stage 2 – Inspection
- Internal/external corrosion
- Hang off assembly – flex joint or taper joint
- Strakes/fairings condition
- Coating conditions
- Armor wire corrosion
- Tensioner condition
- Topside jumper
- Existing integrity management plan and inspection and maintenance data
- Any data to show condition of riser and components
- Example inspections should include visual, annulus vent tests, cathodic protection probes, coatings/barriers, pressure tests, in-line inspection (UT/MFL), optical 3D HD, laser photogrammetry.
Stage 3 – Remnant life analysis
- Proposed riser detailed data
- Proposed operational data
- Proposed environmental data
- Detailed analysis including stage 1 and stage 2 results to prove remaining life capacity
- Forward-looking IM plan
What does this mean for operators?
The level of effort and time required for life extension approval should not be underestimated. BSEE has recommended that operators be proactive and set up 5 and 10 year riser life extension plans well in advance of the end of the current permit. They have also stated that the approval cycle from submittal of a life extension request with sufficient supporting CVA documentation is likely to be 12 weeks. We recommend preparing life extension requests 12 months in advance to allow time for documentation gathering, the 12 week BSEE review cycle, and clarifications, etc.
Early planning with plenty of time for CVA activities in combination with good, documented engineering due diligence will be key to receiving the BSEE’s endorsement. Working with a qualified CVA with prior experience is recommended to make sure all the boxes are checked and the process runs smoothly.
2H’s engineering team is currently working on a number of life extension projects including the life extension CVA of a major operator’s production riser system. 2H has completed CVA projects for over 25 different developments over the years.
Contact our CVA manager on Houston@2hoffshore.com or +1 281 258 2000 for more information on the new policy.
Mike Campbell, Vice President of Engineering, Houston
Mike has been with 2H for 20 years and has extensive engineering experience covering all types of riser systems and subsea equipment. He has particular expertise in numerical analysis, benchmarking of riser design tools, engineering design, monitoring and integrity management.