02 October 2018
In years of working on our customers’ flexible riser systems, we repeatedly see a number of issues. Flexible risers rarely meet their design life, inspection reports with over-simplified analysis, making replacement decisions difficult.
With the cost of replacement ranging from about £15 to £30 million, in the UK North Sea, and the significantly higher cost of riser failure or leakage, the stakes are high.
I believe the difficulties of flexible integrity management are related to data and analysis:
Physical data collection has been relegated to visual inspections and annulus testing, with the occasional assessment of the outer armor wire layer.
Existing analysis tools require oversimplification of the flexible structure and the operating environment to achieve any actionable conclusions.
This has led to overly conservative designs and inaccurate fatigue life predictions, resulting in higher costs and decisions made without understanding the true condition and capability of flexible risers. Our asset management team can provide that understanding, giving you the confidence to achieve safe and economic operation of your flexible risers.
We use Innospection’s MEC-FIT™ (Magnetic Eddy Current Flexible Inspection Tool), which detects corrosion (pitting), cracks (partial or complete), and wire misalignment in the first, second, and into the third armor wire layers.
In addition to this high-fidelity data capture, we’ve developed a Nonlinear Dynamic Substructuring (NDS) solver, FLEXAS™, which overcomes the computational limitations of the industry. FLEXAS™ enables efficient, dynamic flexible riser simulations of detailed, multi-layered, and finite element models in large-scale configurations with direct armor wire stress recovery under irregular wave loadings. Armor wire damage detected during inspections is incorporated into the global FLEXAS™ model, providing remaining fatigue life assessment based on accurate armor wire stress time-histories at the damaged location.
Together MEC-FIT™ and FLEXAS™ offer a unique, state-of-the-art capability not available through any other provider. We call this industry-leading collaboration FlexIQ, which also includes annulus testing and industry-leading experts in flexible riser design, operation, integrity, risk-based analysis, and construction management support for repair or replacement operations.
To improve your FlexIQ, or to discover some of the other tools and approaches in our asset management toolkit, contact Neil.Allen@advisian.com.