Experience in the construction of offshore underwater pipelines in the conditions of the Northern Caspian Sea

The article discusses the problems and natural and geographical constraints in the design and construction of offshore underwater pipelines in the Russian sector of the Caspian Sea. The Caspian Sea is the largest enclosed body of water on Earth, which can be classified as the largest drainless lake. The area of the Caspian Sea is currently approximately 390.000 km2, located at the junction of Europe and Asia. The length of the sea from north to south is about 1.200 km, from west to east from 195 to 435 km, with an average of 310-320 km. Thus, the main problems in the design and construction of underwater pipelines in the Northern Caspian Sea are: the closeness of the Caspian Sea, which causes limited access to equipment from specialized contractors for pipe laying on the seabed; depths of the waters of the Northern Caspian Sea from 4 to 12 meters create difficulties for design and reduce the number of vessels capable of operating at such depths; seasonality of work due to the ice cover in winter; access to the sea through the Volga-Caspian Canal, which is characterized by high congestion, which limits the rhythm of ship movement and affects timely supplies of materials; the need to coordinate design solutions and construction coordinates with the Russian Ministry of Defense due to the intersection of the work area with the area of exercises of the Caspian flotillas; restrictions of the Federal Agency for Fisheries in connection with the conservation of aquatic biological resources; geological complications associated with soil looseness, the presence of areas with low bearing capacity; the formation of ice hummocks capable of damaging the seabed. These factors influence the timing, cost, and technical solutions for the construction of offshore pipelines, which is important to consider for the successful implementation of projects and negotiations with contractors.