On schedule in Sakhalin

Construction giant Aker Solutions is building the largest concrete gravity-based substructure made in Russia, for customer Exxon Neftegas Ltd. The structure is constructed of concrete and will use gravity and water chambers to support a platform for extracting oil and gas.

Five Potain tower cranes are helping to build the large structure, which is part of an oil platform for Russia’s busy Arkutun- Dagi field, off the coast of Sakhalin Island.

The cranes are lifting formwork, rebar, concrete buckets, mechanical equipment and pipe work. The heaviest loads are the pipe work, weighing up to 8t. The substructure is being built at a dry dock in Nakhodka, 180km from Vladivostok, and will be towed to its offshore installation site once construction is complete.

Bjorn Rognlien, engineering manager for Aker Solutions, said it is vital that the project is completed on time and to the highest standard.

“The key challenges on this project are keeping work on schedule and meeting the quality requirements,” he said.

“Although these apply to most projects, on this job, they are magnified. If construction is delayed, bad weather will prevent us from transporting the structure to it final destination. This weather is some of the world’s most extreme conditions, and the structure has to be of the highest quality to withstand the environment.”

There are four Potain MD 485 B cranes and an MDT 218 A from Potain’s topless city crane range working at the Nakhodka yard. The owner of the dry dock, ZAO Rosdorsnabzhenie, owns the cranes and is renting them to Aker Solutions. The cranes arrived in February and March of 2010. The four MD 485 B cranes were assembled in April, and the MDT 218 A began working in August.

All of the MD 485 B cranes are mounted on 2.45m x 245 m mast sections, and each has a maximum capacity of 20t. One crane is working with a 70m jib, while the others are configured with 65m jibs. Working heights for the MD 485 B cranes range up to 83.9m. The MDT 218 A is rail-mounted to allow it to move around the dry dock. This crane is mounted on 2m x 2m mast sections and is working with a jib of 50m and at a working height of 27m.

Michail Vdovin, head of crane and lifting operations for Aker Solutions, said the cranes have been performing well.

“We made the right choice in selecting Potain cranes for this project,” he said. “So far, they have worked great, even though the lifting schedule is demanding. Potain cranes are helping us stick to the tight construction schedule.”

The cranes were sold through Manitowoc’s Moscow office and will be supported throughout their time in Nakhodka by Manitowoc Crane Care.

Jean-Claude Doucene, Manitowoc’s sales director for tower cranes in Russia and the CIS, said the customer wanted to be sure that cranes on this project had the best possible support.

“Timing is crucial on this job, so the customer wanted cranes that were reliable and had the necessary support to handle any problems,” he said. “Starting in November, the waters around Sakhalin Island begin to freeze and will stay frozen until around May. So to navigate the structure properly, the cranes will have to finish their work by the end of 2011.”

When complete, the substructure will weigh 53,000t and will be sunk at a depth of 33.6m below sea level. It will include 52,300m³ of concrete and 19,300t of rebar. The Arkutun-Dagi field is one of three in the Sakhalin-1 project. The Sakhalin-1 project will cost an estimated $10bn–12bn, making it the largest ever direct investment in Russia by an external source.