Evaluation of a novel ultrasonic technique for reliable detection of flooded members in offshore installations

Flooded member detection (FMD) of offshore oil installations involves the detection of sea water in normally air-filled structural members of steel jacket installations. The design and trial implementation of a prototype FMD tool, based around a multi-frequency ultrasonic array, incorporating composite transducer technology and providing data analysis using an expert system are described. Problems associated with more conventional ultrasonic techniques are discussed and improvements offered by the new system are highlighted with a series of operational trials. The tool has a novel ultrasonic array which provides improved efficiency over conventional sensors, and a multi-transducer feature permits identification of corrosion and bad contact conditions generally encountered