Ormen Lange Subsea Condition and Leakage Monitoring

Abstract With the Ormen Lange development, Norsk Hydros subsea solutions are taking technological developments on the Norwegian continental shelf a significant step ahead. Nothing will be visible on the surface when the enormous gas field comes onstream in 2007. High pressure, large water depth and distant location called for a new way of thinking in many ways. This paper will present the leakage and condition monitoring system developed to ensure safe and pollution free operation of the two templates at 850 meters of water depth. Hydro and Naxys Naval Technology started already back in 2000 the development of a new type of subsea monitoring system based on technology originally developed for naval warefare and surveillance. After successful testing on the subsea processing plant, Troll Pilot in 2001, the system was further developed and qualified. On the Ormen Lange Templates one centrally positioned module containing an array of acoustic sensors monitors the complete 44 × 33-m template. The system provides location and magnitude of any leak, structural vibration or valve malfunction on the template.