The pipeline consortium from Switzerland said about 420 miles of the second line of the twin natural gas pipeline has been constructed. The consortium had said work on the second pipeline was moving along at a pace of about 4 miles per day.
The consortium added that it conducted pressure tests on the dry part of the twin pipeline to make sure the steel can withstand operating pressures of as high as 220 bars.
"The pipelines were filled with water and pressurized beyond the planned maximum operating pressure by 25 percent for a minimum of 24 hours," the consortium said. "The pressure tests have been successfully completed and both sections will now be dried and filled with nitrogen to prepare for gas-in."
Russia aims to diversify its European transit options for natural gas through Nord Stream. Disputes with Kiev make Russia's conventional European routes for natural gas risky.
Nord Stream is designed to carry enough natural gas to meet the demands of 26 million homes. The first leg is scheduled to deliver gas directly from Russia by the end of the year. Construction of the second leg will be finished by the end of 2012.