Offshore pipelines will be inspected using the method of magnetic tomography

May 27, 2013

The system AQUA MTM for offshore pipeline inspection using the magnetic tomography method, a product of the joint work of the Russian company NTTs Transcor-K and Malaysian concern PETRONAS, became a winner of the “Spotlight on New Technology Award” at the International Arctic Technology Conference (Houston, USA, 2012).

The following criteria were used by the experts and jury to choose the winners: novelty; innovativeness (brand new solution); approbation; prospects of arousing broad interest from the side of oil and gas operating companies and significant role at the service market. The AQUA MTM victory was determined by a fundamentally new feature – for the first time under operating conditions, it became possible to record mechanical stresses in the areas of metal defects of any nature. This makes it possible to perform the repair work in due time and improve the reliability of the facilities, including non-pigable ones. The high correlation (over 90 %) of safety parameters (Рsaf, Tsaf) received by MTM and common methods: ASME, API, DNV was proven (See Fig.).

The 2-year project on inspection of 200 km of subsea pipelines of PETRONAS using the method AQUA MTM has been successfully completed. It has proven a high technical efficiency of the innovation in detection of potential spots of internal corrosion and sections of pipeline sag resulting from undercurrents. In addition, due to the absence of expenses for the pipeline preparation for inline inspection, a significant economic effect of the innovation was discovered because of a sharp reduction of the inspection time. Another advantage of the technology is its high safety, as there is no risk of the pipeline shutdown in case cleaning pigs or smart pigs get stuck in the reduced bore areas.

One of the important features of the MTM is its unique ability to identify pipeline operation risks in seismically active zones – both underground and underwater, and also in zones of strong undercurrents. The soil washout under the pipeline results in pipe sagging in the sections up to 15 m long. At small diameters (usually up to 500 mm), vertical displacement of the central point of the sagged section can exceed the permissible value, and additional longitudinal tensile stresses combined with circular operating stresses can exceed the metal strength characteristics and cause its destruction. It is impossible to determine the stresses of these anomalies of the stressed-deformed state using conventional non-destructive inspection methods.
Material Supplied by NTTs Transcor-K