| Summary: | As the oil price is relative high, oil companies continue their quest for oil in new areas where it was supposed impossible earlier. 25 % of the world petroleum reserves are assumed to be in Arctic areas. In these areas ice contribute to significant engineering challenges. Ice conditions, emergency response, winterization and extreme low temperatures are some of the challenges that have to be address for design and operation purpose. Ice is an interesting material for an engineer. The knowledge of ice mechanics and physics is essential for understanding how ice forces are developed and acts. The agreement in estimating of forces and development of ice loads have been over time been evaluated for the writing of new structural code. Structural layout proofs to be a significant factor in how ice is managed and therefore in reducing ice actions. However studies have showed that prediction of ice actions is hard to establish and therefore it is difficult to establish proper loading cases. For designing a FPSO in the arctic waters, the classification criteria for floating units need to be complied with. The DNV rules for offshore structure refer to the class rules for ship with additional ice strengthening class. The ISO (International Organization for Standardization) the world's largest developer and publisher of International Standards have issued a draft for a design code for Arctic offshore structures. These two rules and codes have been compared in connection with local structural arrangement. For arctic structures, two design checks ELIE and ALIE are required. These design checks are less established. ELIE ice checks have a return period of one hundred year (10-2) and ALIE one thousand year (10-4). The SEVAN-FPU ice is designed for handling level ice up to 3 m according the DNV Polar 30 Class Notation. Structures are according to the codes required to withstand the ice actions from ELIE within the elastic region. ALIE action will involve plastic damage, but the requirement is to maintain structural integrity to ...
|
|---|