May 2012, Vol. 239 No. 5

TechNotes

12-ton Custom-designed Tool Facilitates Pipeline Maintenance

TDW Offshore Services AS (TDW) designed and built a customized 48-inch SmartPlug® pipeline pressure isolation tool for Nord Stream AG. Weighing 12 tons, the company says it is the largest SmartPlug tool ever produced.

Nord Stream retained TDW to assist in developing contingency solutions for pipelay, pressure testing and planned future maintenance of the Nord Stream gas pipelines. Upon completion, the two 48-inch pipelines will extend 758 miles from Russia through the Baltic Sea to Germany. TDW carried out pre-engineering studies before finalizing the design. The SmartPlug tool was designed, built and tested by TDW at its global headquarters in Stavanger, Norway.

The 48-inch SmartPlug tool will be used to safely isolate pipeline pressure during scheduled pipeline maintenance and potential valve change-outs. It is Type Approved by Det Norske Veritas for a maximum operating pressure of 199 Bar.

“The tool is based on our proven 42-inch SmartPlug design,” said Larry Ryan, director, operations for TDW Offshore Services. “However, the exceptionally large diameter of the pipeline meant that Nord Stream required a SmartPlug tool that was 30% larger. The new SmartPlug tool is not only exceptionally large, but is also capable of isolation at extremely high pressures.”

The SmartPlug pipeline pressure isolation method is designed to provide great value to owners and operators of pipelines. It makes it possible to safely isolate the area targeted for work from hydrocarbons without bleeding down the entire work zone, which is costly and time-consuming. In the case of Nord Stream, there are no mid-line valves available for use, so the entire 758-mile pipeline would have had to be depressurized. Given the minimal amount of gas released while isolating a work area, the SmartPlug tool offers economic benefits while minimizing impact on the environment.