Severn’s longstanding experience optimising valves for the harsh challenges of the North Sea environment continues to underpin offshore success at a global level. This was evidenced in a recent job for the Jubilee FPSO operated by MODEC off the Ghanaian coast.
“A combination of extreme environmental conditions and high performance demands were pushing flow control valves on the FPSO far beyond their original specification,” explains Adam Eckersley, Technical Engineering Manager at Severn Unival. “Valve components were exposed to warm aerated seawater, and the resulting corrosion led to performance issues and regular production interruptions, with significant financial consequences. The damage was so severe, that in some cases valves had to be replaced or overhauled on a six-monthly basis.”
In 2013, Severn upgraded the valves with an Inconel cladding. This proved to be an effective solution, resulting in reliable and efficient operation. However, at a later date the FPSO began to experience production challenges associated with assets outside the valve population. At this point, insights gathered by Severn during inspections of internal valve components during the overhaul unlocked new measures to enhance the vessel’s technical capabilities, to improve safety, reliability and performance.
Aberdeen-based oil and gas consultancy Core was appointed by MODEC to develop a strategy to overcome the FPSO’s wider performance issues. Overlaying Core’s analysis of actual process conditions and requirements with Severn’s Repair Intelligence from the earlier overhaul facilitated more precise application of engineering skills to enhance the vessel’s performance. A critical enabling factor was Core’s revelation that the vessel’s actual process temperature was 40°C as opposed to the specified 60°C. This had a major impact on material selection, clearing the way for Super Duplex to be used.
“All the pressure control valves and flow control valves have been switched for highly-engineered Super Duplex replacements manufactured by Severn,” Adam continues. “They were completed and shipped four weeks ahead of the planned shutdown earmarked for their installation. And the Inconel-clad FVs supplied in 2013 have been overhauled, upgraded and retained as spares.”