Morten Strengelsrud, our Head of Department for riser integrity has been working with monitoring of flexibles risers since 2012, focusing specifically on vent gas monitoring (VGM) system.

6 February 2017

“The first VGM system installed by FORCE Technology was deployed on an FPSO in the Norwegian sector in 1999. Since then, we’ve refined the system to deliver precise data that monitors the current state of the riser annulus. This historical data enables us to foresee possible scenarios and address potential issues developing in the near future.

A VGM system continuously monitors annulus gas flow and annulus free volume, and provides this data and the integrity status directly to the onboard control system. By analyzing trends, we can detect abnormalities and issue warnings or alarms when actions are required to maintain integrity – invaluable information for operators.

Incremental changes over time reveal the current and future state of the riser. Analysis of these changes will allow us to predict the amount of water accumulation at any given time. Water ingress could create a highly corrosive environment combined with CO2 or H2S, so proactive measures are crucial.

Gas sampling in bottles provide a basis for analysis at any given time. We are currently looking at a new feature that would allow the operators to receive an automated digital analyses of the data (stored in the cloud).

We see an ongoing trend of operators seeking continuous monitoring for increased control and long-term cost-efficiency. To achieve optimal results, we recommend planning for VGM systems during the pre-FEED phase. This approach allows for a cost-effective, standardized solution that is tested, proven, and quickly installed.”