TDW Offshore builds customized pipeline isolation tool

TDW Offshore says that Nord Stream AG will use its new 48-in. SmartPlug tool to safely isolate pipeline pressure during scheduled pipeline maintenance and potential valve change-outs.

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-in. pipelines will extend 758 mi (approx. 1,220 km) from Russia through the Baltic Sea to Germany. TDW carried out a series of pre-engineering studies before finalizing the design. The SmartPlug tool was designed, built and tested by TDW at its global headquarters in Stavanger. The new 48-in. SmartPlug tool will be used to safely isolate pipeline pressure during scheduled pipeline maintenance and potential valve change-outs. It is currently Type Approved by Det Norske Veritas for a maximum operating pressure of 199 bar (2,886 psi).

"The tool design is based on our proven 42-in. 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 value to owners and operators of pipeline systems. TDW says the tool 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 1,220-km pipeline would have had to be depressurized, taking a significant amount of time. Given the minimal amount of gas released while isolating a work area, the new SmartPlug tool offers more than economic benefits, according to TDW. The company says that it is also very effective in minimizing impact on the environment.