arctic


Flow of ice around and under floating structure, and its accumulation inducing loads on the floater and the appendages


IceStream JIP launches


A new JIP evaluates floaters and their appendages in a flow of ice particles. Hannes Bogaert, h.bogaert@marin.nl


In 2011, the Dutch offshore industry joined forces to extend its knowledge about opera- tions in Arctic conditions. This has resulted in the initiation of the Arctic Operation Hand- book JIP, led by Heerema Marine Contractors and supported by Shell, Bluewater, SBM Offshore, Boskalis, IHC Merwede, Huisman, IntecSea, Canatec, TU Delft, TNO, Imares and MARIN. This project identifies the available, and the required guidelines for operations such as dredging, pipe laying, trenching, platform installation and decommissioning.


In the preparation phase of this project however, it already became clear that guidelines are missing for the evaluation of measures to control the flow of ice around and under offshore floating struc- tures. This subsequently resulted in the creation of the IceStream pilot project.


During operations in Arctic conditions, it is very likely that ice will flow around and un-


12 report


der floating structures. But it is important to prevent ice accumulating extensively, inducing loads that exceed design limits. The flow of ice can be controlled by optimising the shape of the floater, or with methods to physically manage the ice, such as ice breaking or by breaking up any accumulation that might occur by using water jets for example.


Guidelines needed In order to make a sound evaluation of the measures to control the ice flow, engineers are missing guide- lines that describe the ice conditions that need to be assessed, what the appropriate way is to model the ice flow, acceptable levels of ice accumulation, the best design and the operational practice to control the ice flow. The pilot project is initially investi- gating the most appropriate way to model the ice flow.


All over the world numerical models are developed to study the behaviour of floating


structures in ice. MARIN contributes to these developments by drawing up the most suit- able way of numerically describing the ice field and the loads on the ice.


The ‘Egg Code’ refers to an oval form and associated coding describing the concen- trations, stages of development and the form of ice, (see the Manual of Standard Procedures for Observing and Reporting Ice Conditions (MANICE)). Together with Gus Cammaert from TU Delft and Wim Jolles from Canatec, MARIN is working out a method to translate the ‘Egg Code’ on ice charts into a numerical description of the ice field. The translation will be validated against aerial observations and those that have been made by MARIN onboard the James Clark Ross (see page 10).


As the pilot project is moving on, a new Joint Industry Project IceStream is being set up. Participants are welcome to join.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24