The 177 km Dzhubga – Lazarevskoe – Sochi Pipeline is part of the infrastructure being developed by the Russian Government in preparation for the 2014 Winter Olympics, and is intended to reduce the energy deficiency on the Caucasian coast of the Black Sea. When complete, its transport capacity of 3.8 Bcm/a will ensure gas supply to Olympic venues in the mountainous area of Sochi, as well as to the many resorts in the region.

A large proportion of the 530 mm diameter pipeline will be offshore, with a 159.9 km section in the Black Sea approximately 4.5 km seawards from the coastline. The landfalls for the pipeline will be at Dzhubga, Novomikhailovka, Tuapse, and Kudepsta.

Gazprom will own and operate the pipeline, while Stroygazmontazh has been contracted for construction. Stroygazmontazh, a long-time partner of Gazprom, has worked on the construction of several other major Russian pipelines, including the Sakhalin – Khabarovsk – Vladivostok Gas Pipeline, the Gryazovets – Vyborg Pipeline, and the Pochinki – Gryazovets Pipeline.

Construction work on the Dzhubga – Lazarevskoe – Sochi pipeline began in September 2009, and is scheduled for completion in June this year. The project has required detailed planning and considerable technical expertise, as the route traverses difficult and varied terrain.

Environmental challenges onshore

On land, the pipeline must negotiate large changes in elevation and steep rock cliffs along the coast, and horizontal directional drilling (HDD) has been used to install the pipeline in these areas. In addition, the Black Sea coast is part of the Sochi National Park, and one of the most carefully conserved ecosystems in Russia. To avoid harming local wildlife, pipeline installation was scheduled to take into account the lifecycle of native fauna. In addition, HDD was used to install the shore approaches near Tuapse and Kudepsta, further minimising disruption to this fragile coastal environment. According to Gazprom, this is the first time that HDD has been used in a shore approach in Russia.

The use of HDD not only helped preserve the coastal ecosystem, but also allowed the pipe to negotiate the steep coastal cliffs. While ultimately successful, engineers were forced to innovate to overcome some considerable technical challenges.

A Gazprom spokesperson said “During directional drilling, the construction team faced the problem of drilling mud disappearing into natural cavities or ‘voids’ in the rocks. The team found a solution by filling the voids with concrete: after solidification, drilling was able to continue.”

In addition to HDD, microtunnelling was used to install the pipeline at river crossings, which offered further environmental protection.

Securing the pipeline offshore

The offshore component presented its own challenges. The seabed of the Black Sea is notoriously silty, so the pipeline was buried to a depth of 1 m to provide maximum stability and security. Also, the subsea route travels close to dumps of mines and weapons dating from World War 2. Gazprom said that routeing around these hazards required careful planning, and construction required strict adherence to safety. Indeed, throughout the project, compliance with safety regulations has been given a high priority, and mandatory weekly safety exercises have been conducted throughout the project.

The decision to construct a gas pipeline on the seabed has reduced the alternative of construction through industrial, agricultural, and forest terrain onshore. While making the project more expensive, Gazprom considered these various environmental protection measures to be more than worthwhile, and the company reports that all the work was undertaken with minimal environmental impact.

Environmental and logistical challenges overcome, the Dzhubga – Lazarevskoe – Sochi Pipeline will be ready well in time for the 2014 Winter Olympic Games.