Blue Stream Natural Gas Pipeline, Russia/Turkey

In 1998, Russia and Turkey signed an intergovernmental agreement for the sale of 565 billion cubic feet (bcf) per year of Russian natural gas. In order to implement the agreement, the Blue Stream Pipeline Company - an equal partnership between ENI and Gazprom - was formed to operate a pipeline between the two countries via the Black Sea.

The basic and detailed design phases of the pipeline were awarded to Saipem under an EPCI contract.

The pipeline cost US$3.4 billion. The pipeline will carry, at full capacity, 16 billion cubic metres of natural gas from Russia to Turkey.

BLUE STREAM PIPELINE

The pipeline consists of three main parts. The route comprises a 222 mile section in Russia from Izobilnoye to Dzhugba on the Black Sea Coast (the Russian onshore section) a 235 mile section on the bottom of the Black Sea connecting Dzhugba to Samsun on the Turkish coast (submarine section) and a further 300 mile link from Samsun to Ankara (Turkish onshore section).

The pipelines consisted of a pair of 24in OD steel lines with a wall thickness of 31.8mm. These lines were installed in parallel to each other at a nominal separation distance of between 5m and 100m excluding the Russian Continental Slope, where different routes were selected. The routes were called E1 (Eastward route) and W2 (Westward route).

PIPELINE ACROSS THE BLACK SEA

The shallow water sections of up to 380m were installed by the Castoro Otto. The deep water sections of up to 2,150m were installed using the J-lay method by the crane vessel Saipem 7000. The offshore work began at the end of mid 2001. Saipem 7000 crossed the Bosphorus Strait on August and began the deep-water laying work in October 2001.

Previously, the Saipem 7000 was modified with a novel pipe installation system, essentially making it the only ship in the world capable of laying pipelines at such depths.

Saipem developed a purpose-made welding system comprising three Presto twin-torch welding units mounted on a rotating carousel. This system uses strings of quadruple joints, 12.1m each welded into 48.8m units. These 'quadjoints' were transported to the vessel from an offshore base.

The prefabrication of the quadjoints required a purpose-built fabrication plant in Samsun, occupying 90,000m². In total, this loaded out 14,557 joints which required 43,671 girth welds and 8,673 anodes as well as field coatings. SAWL 1 448 SF grade linepipe was used. A consortium of Nippon Steel, Sumitomo, NKK and Klawasaki steel supplied 690km whilst Corus UK supplied a further 89km of linepipe. Much was coated by BSR in Hartlepool and Price coaters in Leith.

The pipelines system also required 17km of 652mm OD by 52.7mm buckle arrestors. There were also 10,438 bracelet anodes from the UK and another 15,032 from Singapore.

PIPELINE SHORE PULL-IN

The linking of the pipeline sections also involved shore approach works at the Russian and Turkish landfalls. There are emergency shutdown valves at the interfaces. Pre-trenches were excavated at a water depth of 10m, using onshore excavators and dredgers. Pipe joints of 12.2m for the shore pull-in were coated with 45mm of concrete. At the Russian side the Castoro Otto, minus stinger, pulled the W2 line ashore first, then the E1 via a 300t return sheave installed on the beach. It then proceeded to the Turkish side.

In October 2002, construction on the pipeline was completed and natural gas supplies through the Blue Stream began in February 2003. The flow of natural gas will gradually reach 16 billion m³ in 2007 in accordance with Natural Gas Purchase Sale Agreement.

Click here for printable version