Next month, Aker Kværner Pusnes will deliver two arctic crane offloading systems to Sevmorneftegaz’ Prirazlomnoye development in Russia’s Pechora Sea under a NKr 90 million contract. These are the first deliveries of the system, which has been developed for offloading oil from a fixed platform to a shuttle tanker, according to Reidar Grindheim, the company’s marketing manager for offshore systems.
The two offloading systems will be at opposite corners of the platform, to allow loading from the optimum direction, taking into account ice, wind, and current conditions. Each system consists of a crane, mooring line, and offloading hose. The mooring line, which is stored on a releasable hawser handling winch, is first passed to the shuttle tanker then moored in a tandem configuration about 70 m from the platform.
An important requirement for the 20-in. offloading hose is that it must not come into contact with the sea or ice. It is attached permanently to the crane, which has a knuckle-boom extending 70m. Between offloading operations, the crane retracts and the hose is filled with inert gas. Aker Kværner Pusnes’ sub-supplier Hydramarine, which has also built the two Prirazlomnoye units, developed the unique crane design.
Offloading capacity through the hose is 63,000 bbl/hr. The system’s safety features include an emergency shut-down valve that can halt crude flow in just five seconds, crane overload protection, and fail-safe winch brakes.
Aker Kværner Pusnes' arctic crane offloading system will allow crude to be directly offloaded from the Prirazlomnoye platform to a shuttle tanker despite extreme cold and ice.
Aker Kværner Pusnes, formerly Maritime Pusnes, worked closely with the Russian engineering contractor Rubin for the development. One of the major challenges was selecting materials capable of withstanding the extreme conditions at Prirazlomnoye, which is within the Arctic Circle at about latitude 70° N. Design specifications require loading at temperatures down to -40° C.
The Prirazlomnoye platform, which will be in a water depth of only 20 m, will have a steel caisson foundation including oil storage facilities. The major part of the topsides will be the refurbished module from the decommissioned Hutton platform in the UK.
Aker Kværner Pusnes is also bidding for the bow loading facilities for the two Prirazlomnoye shuttle tankers. The supplier, which has focused for several years on cold water projects in the Russian sector, is currently delivering specially developed bow loading systems for five shuttle tankers, which will work on ExxonMobil’s Sakhalin I development.•
