Page 56: of Offshore Engineer Magazine (Jan/Feb 2014)

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Pipelines

The inline inspection tool arrives at Lubmin,

Germany.

pipeline. The tool works best at a speed refurbished by Rosen and taken by land A magnetic fux leakage sensor detects of 1.5m/sec. A speed control valve is back to the Russian Landfall Facilities to any material loss or corrosion in the mounted to the front of the tool. It allows start its run down the second pipeline. steel, or between the steel and the outside the regulation to a preset tool velocity in Inspecting the second Nord Stream concrete coating. A strong magnetic feld order to optimize measurement conditions pipeline with the three tools started mid- magnetizes the pipe wall and an electro- independent from the gas fow. A high- August, and was fnished at the end of magnetic sensor records any changes in density memory device is used to record September. magnetic feedback from the pipe steel during the inspection, for later analysis. Nord Stream believes the data from through its entire 41mm thickness.

An internal diameter (ID) mapping the inspection tool is the longest data Nord Stream believes this is the stron- caliper detects and characterizes any set from an inline inspection ever gest magnetic feld ever developed for deviations from the original pipe shape, recorded. With more than 2000 measure- an inline inspection tool: even inside a some even smaller than 1mm. Internal ment channels and one sample recorded 41mm pipeline joint, it creates a mag- diameter changes, ovalities and dents, every 2.5mm over the pipeline length of netic feld leaking out to 6m (approx. will be detected, localized and identifed. 1224km, each tool arrived in Germany 20ft.) distance.

The tool is also able to detect and map with more than 1,000,000,000,000 (1012), An inertial navigation system, or XYZ- any misaligned welding joints. or more than one trillion, data samples. unit, on the inspection tool, maps the

The sensors function by measuring Data sets recorded in both lines are pipeline’s geometry, to detect any incre- incremental changes in how far any of being evaluated. Preliminary results have mental movement in the pipeline that the spring-loaded caliper arms that guide shown the pipelines are free of any corro- could result in bending strains. The tool the sensors along the pipe wall are bent sion spots or deformation. measures the strain placed on the inertial when the sensors run through even very Corrosion was not expected during gyroscope sensor when it traverses a small dents or ovalities. the operation of the pipelines. Gas going curve in the pipeline.

The inline inspection tool is able to through them is constantly measured at It was used together with informa- detect variations in the pipeline manu- the inlet, to exclude contamination from tion from the external inspection, and facturing process to a sub-millimeter water. The internal fow coating seals the confrmed that the twin pipelines shifted level (below 0.04-in.) and provides a very steel from potential corrosive infuences. only marginally after operating under accurate baseline for future inspections. The inline inspection tool also has a pressure.

At the end of July, the inline inspection shallow internal corrosion sensor, con- An inline inspection is now scheduled tool was received at the German Landfall sisting of a proximity sensor attached to to take place every few years on the Nord

Facilities, after a run time of 10 days. the caliper arm, which can map surface Stream pipelines, to confrm the absence

The recorded data on the tool was metal loss defects. Small defects on the of corrosion or mechanical defects, with retrieved and sent to post processing surface of the inner pipe wall change reference to the extensive baseline data and a three-stage analysis. The inline the sensor’s proximity to the pipe wall, now gathered, including its geographical inspection tool was then completely which the sensor is measuring. coordinates.

January 2014 | OE oedigital.com 58 056_OE0114_pipelines2 Nord Stream_BLJ.indd 58 12/19/13 6:33 PM