With many offshore installations in the UK and Norwegian sector of the North Sea now reaching or being in excess of their original anticipated design life, usually 20 years, there is a particular need to evaluate approaches to the structural integrity management by offshore operators. Ageing processes can affect the structural integrity of the installation and demonstration of adequate performance beyond its original design life is thus a necessary requirement.
At Z-Subsea we provide Life Extension (LE) assessments consultancy to operators and/or Independent Verification Bodies (IVB) on the aged oil and gas assets based on the procedures outlined in NORSOK N-001, ISO 19900/19902, ISO13822 and API RP2A-WSD using the following steps:
- Gathering relevant historical and current data from the asset
- Generating values not available such as applied stresses using Finite Element Analysis (FEA) techniques, pushover/Redundancy analysis, etc.
- Understanding of the degradation processes on the asset with reference to earlier Risk Assessments reports, inspection data, etc., if available. If none available, Z-Subsea could perform risk-based integrity studies to overcome this gap (Section 6.1).
- Use of best technology / latest assessment methods to determine remaining life and safety margins on the asset and hence checking the need for repair
- Development of new techniques (e.g. online monitoring) implementation strategy