Sea spray icing is one of the major challenges when operating in Arctic conditions. DNV GL is now launching an industry collaboration that will develop a simulation model that bridges functional winterisation requirements and real physical conditions for drilling rigs, production platforms and vessels. Experts from both the maritime and oil and gas industries are invited to join the new joint-industry project (JIP) named RigSpray.
DNV GL Arctic technology programme director Per Olav Moslet said: "We aim to ensure that the design of icing-mitigation measures delivers both safety and cost benefits."
Today, the operational capabilities of conventional vessels and offshore structures do not meet the requirements for operating in harsh Arctic conditions. The trend towards increased activity in the Arctic and especially the ice-free areas means that the issue of sea spray icing needs to be addressed.
Mr Moslet added: "Sea spray icing poses a threat on multiple levels, from blocking the operation of essential components to jeopardising stability and integrity and thus leading to an increased risk of capsizing."
A number of recognised standards, such as DNV GL’s offshore standard Winterisation for Cold Climate Operations (DNV-OS-A201), provide guidance on mitigating ice accumulation using specified anti- and de-icing procedures. The standards available today provide requirements for safety functions and to some extent describe mitigation solutions, but do not give a specific answer to how and where they should be implemented. An optimal answer to those two questions can be given by better understanding the physical phenomenon of sea spray icing via simulation and measurements. Overall, the benefit would be an improved safety and working environment in Arctic conditions.
To deal with this, DNV GL is establishing the new RigSpray JIP and invites maritime and oil and gas experts to participate.
DNV GL project manager for the RigSpray JIP Olga Shipilova said: "We have already made progress in addressing the challenge through the MarIce JIP, where DNV GL worked together with Statoil and the Norwegian University of Science and Technology to create the world’s most advanced marine-icing model.
"However, this needs to be developed further. The present model still lacks an accurate representation of sea spray, which is a very important parameter for ice formation. Present knowledge of sea spray generation is limited to very local metocean conditions and sporadic vessel designs. We certainly need to fill this gap with more experimental and modelling studies."
The first step is to develop a software tool to further understand sea spray icing using mathematical modelling and measurements. This will provide a solid basis for extending local ice estimations to a wider spectrum of metocean and structural conditions, which in turn will lead to safer and more cost-effective winterisation solutions for drilling rigs, production platforms and vessels operating in cold climate areas.