Since the introduction of inline inspection tools (ILI) more than 50 years ago, there have always been pipelines that were considered unpiggable. Typically, it is a combination of various circumstances relating to pipeline design, operating conditions, and/or characteristics of the medium that prevents a successful inline inspection using traditional methods. At ROSEN, however, we refuse to accept this as a fact. This is why we have dedicated an entire diagnostics division to finding ILI solutions for what we refer to as challenging pipelines.
ROSEN Norway (former KTN AS) is a technology company specialized in self-propelled tethered tool inspection technology for challenging pipelines. Different types of technologies, including ultrasonic wall thickness and crack measurement (angular beam pulse echo, Time of Flight Diffraction and Phased Array) and Eddy Current, and different types of propulsion elements, including bi-directional self-propelled (crawler) and pumped modules, are available for the specialized ILI tools. The system is capable to measure crack depth and profile quantitatively, data is collected on the way in and out and the results are visible in real-time. Tethered technologies are capable of inspecting pipelines with a 6" or larger diameter, and up to 12 km in length.
The paper will explain the technologies used and the specifications achieved. Furthermore the unique ability of the system to navigate complex pipeline geometry will be explained by a case study of a 10” offshore oil riser. For this inspection the tethered tool safely negotiated a total accumulated bend angle of 1188° (17 bends) whilst successfully inspecting the pipeline for wall thickness and cracks.