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RigSpray – predicting sea spray on Arctic offshore structures

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RigSpray - Sea spray icing poses a threat on multiple levels
Sea spray icing poses a threat on multiple levels from personal safety and hindering operation of essential components to jeopardizing the stability and integrity of offshore structures and vessels.

Objectives

The primary objective of RigSpray is the development of knowledge, models and a tool to estimate marine icing loads required for design. Design requirements are given by the regulatory bodies, such as the Petroleum Safety Authority (PSA), and specified in for example NORSOK N-003 and ISO 19906.

Secondary objectives that will support the main objective are:

  • Development of instrumentation for long-term measurement of sea spray (flux, frequency and spray-duration)
  • Measurements of sea spray on offshore structures (semi-submersible, ship shaped and cylindrical shaped)
  • Development of a sea spray model suitable for implementation in the icing model (mathematical and/or physical)
  • To study and quantify uncertainties in the sea spray icing model (water transport, heat transport, melting)


Project Summary

A key element of the project will be the development of a marine icing model that is able to estimate ice accumulation on offshore structures using historical metocean data. This will be obtained by refining an existing numerical model to represent heat transfer and spray flux more accurately whilst maintaining an efficient numerical code. This tool shall be able to estimate marine icing loads that enables the user to calculate relevant annual probability of exceedance for loads from marine icing for a given installation and location.

The rate of ice accretion is determined by the amount of water hitting a surface per time and the heat transfer from the surface, and both must be accurately predicted for marine icing models to give reliable results. Due to a limited number of available sea spray measurements, all existing models are associated with a large uncertainty in the amount of sea spray. The project aims to reduce the uncertainty related to prediction of sea spray production to an acceptable level by performing measurements on a number of installations offshore. The project includes the development of suitable equipment for reliable long-term measurements of sea spray flux, frequency and duration. The results from these measurements will be used as a basis for a sea spray model included in the tool for calculation of marine icing.


Budget and schedule

RigSpray JIP has a budget of 18.6 million NOK. The project started in 2016 and should last for three years. The project receives financial support from the Research Council of Norway (PETROMAKS 2), Statoil, ENI, OMV, Aker BP and Lundin. The project is managed by DNV GL and executed in collaboration with Sintef ICT and University of Oslo.


Last modified on 12 May 2017


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Joint Industry Projects - RigSpray – predicting sea spray on Arctic offshore structures

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