RBI is a well-established and valuable strategy for managing pressure system integrity.
However, RBI relies on knowing wall thickness loss but the built-in errors of the ultrasonic thickness measurements used, mask the wall loss trends we are looking for.
Experience gained over a 7-year programme of 14 assets showed that for every 100 UTM readings taken, less than 2 readings deemed to be a genuine integrity threat of immediate concern.
As the industry strives for increased cost effectiveness, more efficient anomaly detection is required from a UTM strategy, whilst maintaining integrity assurance.
In short, we could cut the number of inspection points significantly…..but which ones?
EM&I’s ANALYSE System uses statistical analysis of UTM data sets to calculate the probable minimum thickness of a corrosion circuit and checks if it breaks any alarm levels….but it does this with fewer than 50% of the readings normally required.
What are the ANALYSE steps?
- Optimise RBA scope and select relevant inspection locations
- Technician collects UTMs and inputs to the ANALYSE handheld
- As soon as ANALYSE has enough data to calculate the minimum probable thickness and with the agreed confidence level, no further UTMs are required.
- ANALYSE identifies problem areas, and corrosion patterns and alerts the technician and the integrity engineer.
In this way ANALYSE not only maintains, but improves the integrity assurance of UTM data, with a quantified confidence level and insights into the early onset of localised corrosion, erosion and wall loss.
- ANALYSE improves on traditional RBI methods and delivers reduced inspection scopes, demonstrated at circa 50% of the conventional number of UTMs
- Subsequently, inspection costs are reduced, with improved safety and carbon emissions through reduced POB
- More resource can be allocated to additional inspection, repair, and maintenance activities
- ANALYSE improves integrity assurance, through the introduction of quantified confidence levels of the minimum reading relative to wall thickness limits
Is it proven?
The statistical analysis methods behind the ANALYSE System has been reviewed and is independently endorsed by the Imperial College of London statistical department. The System itself has also been successfully piloted with a number of Oil and Gas Majors, achieving 50% to 72% reductions in required UTMs.
EM&I’s ANALYSE system is also integrated into the RBA and Annual Piping Inspections for a Fleet of 13 FPSOs across the world.