Robots to help maintain offshore infrastructure
A healthy oil and gas infrastructure in Europe is crucial for the economy, representing a challenge that involves optimal maintenance of process plants, pipelines and other crucial components. Maintaining offshore infrastructure can be achieved by exploiting technology such as non-destructive testing (NDT) techniques and robots deployed through remote operating vehicles (ROVs). This was the aim of the EU-funded SUBCTEST project. Currently, little routine NDT is conducted on critical sub-sea welds in offshore assets. Available solutions do not operate below 30 metres in depth, relying instead on dangerous diving missions. A more compact class of ROVs envisioned by the project aimed to overcome limitations posed by the size and weight of NDT equipment. Specifically, SUBCTEST worked on developing an ROV-deployable platform for three NDT methods, namely alternating current field measurement (ACFM), phased-array ultrasonic testing (PAUT) and long-range ultrasonic testing (LRUT). This technology would enable improved inspection of sub-sea structures such as braces, nodes, risers, mooring chains and flow lines, detecting external cracks, defects, corrosion and fatigue. To achieve this objective, the project team worked on reducing the mass of the manipulator that carried the ACFM, PAUT or LRUT transducers and/or sensors so that they could be deployed by an observation-class ROV. Efforts involved maintaining buoyancy of the equipment and developing cost-effective design such as the use of a simple games controller to operate the LRUT manipulator. Another important achievement involved designing a smart ACFM manipulator using a saddle that gives 170-degree coverage around pipe circumference. The team also simulated ROV deployment on an offshore platform to ensure reliability of the system. Software and firmware enhancements improved performance of the rover and its components. All these achievements have led to the development of a viable platform for ROV-deployable NDT systems that can be used to detect corrosion and cracks in offshore infrastructure. Much exploitable knowledge has emerged in this area from the project as well as a business plan to commercialise the platform. If the technology is exploited, it will increase the safety and efficiency of Europe's critical offshore industry, minimising precarious diving maintenance missions as well.
