Abstract

This paper presents the overview of the Pre-Service operations for the Aasta Hansteen field development. The paper also covers the execution challenges, supporting engineering and procedures followed for the various activities.

The Aasta Hansteen Field development at a water depth of 1300m is the deepest field on the Norwegian Continental Shelf (NCS). The field is remotely located north of the Arctic Circle, in a particularly harsh environment 300km off the coast of Northern Norway, with 140km to the closest offshore installation.

In the past, the pre-service marine operations for Spar platforms were completed at the offshore field locations. The Aasta Hansteen development presented the opportunity to complete the entire pre-service operations in the sheltered waters of the deep Norwegian fjords, making it a unique, first-of-a-kind inshore pre-service operations for a Spar platform ever executed. This advantage also helped to significantly reduce the cost and complexity of the pre-service operations effort for the project.

There were several firsts in the industry for the Aasta Hansteen Spar platform, namely; Largest and heaviest Spar delivered, First Spar in Norwegian waters and subject to Norwegian rules, first full pre-service scope inshore in a fjord, first requirement for Structural Tank Inspection on a Spar Hull, first requirement for a Submergence Test, largest topside catamaran mating at 22,500 Te. Many of these firsts heavily influenced the planning and execution of the Pre-Service Operations for this project. The significance of these are also highlighted in this paper.

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