Rapid Response Platform Monitoring to Verify Post-Hurricane Structural Integrity
Hurricane Harvey impacted a number of offshore platforms in the Gulf of Mexico. The structural integrity of affected platforms needs to be verified and rapid response platform monitoring can help operators achieve that quickly and simply.
12 Sep 2017
BSEE Post-Hurricane Inspection Notice
The Bureau of Safety and Environmental Enforcement (BSEE) issued a Notice to Lessees (NTL 2017-G01) requiring post-hurricane inspections of affected platforms in line with API post-hurricane structural inspections requirements (API BUL 2HINS – Guidance for Post-Hurricane Structural Inspection of Offshore Structures).
Platform Integrity Options for Operators
The API 2HINS guideline allows several methods of engineering checks in order to confirm platform integrity. Among these methods is a comparison of the platform’s natural period (the period at which a structure tends to naturally oscillate without an external force applied) before and after the hurricane. If the natural periods match, this indicates that the platform is operating as intended and confirms the acceptability of the engineering check.
Other methods include comparing measured metocean data during the hurricane (wind, current, wave and storm surge) to those used in the platform’s design. If any measured metocean parameters exceed those used in design, a structural analysis of the platform can be used to confirm integrity. Inspections of specific components may be required if the structural analysis shows that they may have experienced excessive loading.
How Does Rapid Response Monitoring Work?
2H has used rapid response monitoring to verify structural integrity for numerous clients. We specify field-proven, off-the-shelf sensor equipment and mobilize it within 24 hours. It is installed by a 2H engineer at strategic locations on the platform to measure natural response period. Sensors typically measure acceleration and angular rate. Automated data analysis calculates the platform’s natural response period and confirms integrity.
Recent Platform Monitoring Results
We recently deployed platform response monitoring equipment on a fixed platform in the Gulf of Mexico. Four natural frequencies were identified, as indicated by spikes in the frequency domain acceleration and angular rate response in the chart below. Comparisons of the natural periods to earlier measurements demonstrate that structural integrity of the platform was maintained.