The procedure, known technically as “Above Water Tie-In,” involved retrieving the nearshore pipeline and offshore pipeline from the seabed, lifting them above water and welding them together. The total weight that had to be lifted for the operation was approximately 409 tons. After a thorough inspection of the weld, the pipe was carefully lowered to the seabed at a depth of 32 meters. This operation was carried out on both lines in Russian waters in January and February this year, and near the Turkish coast in March.
The pipelaying in deep waters was carried out by Pioneering Spirit, the world’s biggest construction vessel, while the shallow-water pipelaying was conducted by Lorelay.
With the completion of the Above Water Tie-In Procedure, a physical connection between the landfall facility near the Russian city of Anapa and the Receiving Terminal near Kiyikoy in Turkish Thrace is realized.
Russkaya Compressor Station, which will provide the necessary pressure for the gas to traverse through the Black Sea, and the Anapa landfall facility of the TurkStream pipeline system are already complete and on stand-by.
With the completion of the Receiving Terminal in Kiyikoy later this year, TurkStream will be ready to commence operations. Natural gas flow through TurkStream is planned to start by the end of 2019.
TurkStream is the project for a gas pipeline stretching across the Black Sea from Russia to Turkey and further to Turkey’s border with neighboring countries. The first line of the gas pipeline is intended for the Turkish consumers, while the second line is designated for the Southern and South-Eastern Europe. Each line will have the throughput capacity of 15.75 billion cubic meters of gas per year. South Stream Transport B.V. has been carrying out project activities with regard to the offshore gas pipeline.
Near Kiyikoy in Turkey, construction of the Receiving Terminal is ongoing. In Russia, near Anapa, landfall facilities have been constructed, and currently, pre-commissioning activities are being carried out. They will be completed in 2018.
Allseas Group is the world’s leading company in offshore pipe-laying and subsea construction. The company is focused on comprehensive project implementation, including design, material and equipment procurement, construction and commissioning. Allseas is the construction contractor for both lines of the TurkStream offshore gas pipeline.
Pioneering Spirit is the largest construction vessel in the world, 477 m long and 124 m wide, designed for deep-water pipe-laying, installation and removal of large oil and gas offshore platforms. The vessel is owned by Allseas.