Nord Stream Completes Comprehensive Inspection

Nord Stream has concluded a comprehensive inspection of the internal condition of both pipelines, as part of its long-term safety and pipeline integrity management strategy. A measurement tool about seven metres long and weighing more than seven tonnes was sent through the pipeline from Russia to Lubmin, Germany, travelling at 1.5 metres a second propelled by the gas pressure. The pipeline inspection gauge (PIG) collected high-resolution data on material integrity along the 1,224 kilometre route. The journey for Russia to Germany took ten days.

This was the first time that a pipeline of this length and a wall-thickness of up to 41 millimeters has been analysed in this way. For the inspection run, a device with one of the strongest magnetic fields was developed by ROSEN Group in Lingen, Germany. The “intelligent PIG” has an array of electronic sensors, which screen the material integrity and the geometry of the pipeline. The PIG has collected over one Terabyte of data on its journey from Russia, and the data was recorded at a rate equivalent to 12 Megabits per second, 30 times faster than cellular data networks.

The high-resolution measurement technology can detect smallest changes in the condition of the pipelines. The exact geographical position of the pipelines is also being documented. The first evaluation of the results confirms that the pipelines have moved only minimally while being operated under full pressure and that there has been no corrosion or deformation.

In 2012 and early summer of 2013, Nord Stream had already examined the external condition of both pipelines. This external visual and instrumental inspection of the pipeline was conducted via remotely operated vehicles (ROVs) followed by support vessels. The results of the internal and external inspections form the baseline data for regular inspection cycles in the coming years. This will allow any potential changes in the position of the pipes, minimal corrosion and even the smallest mechanical defects to be detected at an early stage.