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Autonomous real-time sea spray measurement system for offshore structures

Autonomous real-time sea spray measurement system for offshore structures

Category
Journal publication
Abstract
Sea spray icing can pose a risk to offshore structures in cold climate, affecting the operability and in the worst case the stability of the structure. One of the most uncertain parameters when attempting to estimate the design load from sea spray icing is the flux of sea water reaching the topside. Typically, the only available measurements of sea spray have been recorded on smaller fishing or navy vessels, with estimates varying with orders of magnitude and being of less relevance for large, stationary offshore structures. One of the challenges with observations of sea spray has been that the applied measurement principles have required frequent manual intervention by dedicated personnel. The present paper describes a real-time measurement system designed for recording sea spray flux on producing offshore oil and gas facilities as part of the joint industry project RigSpray. Two of the principal requirements for the system was that it had to be autonomous and that it satisfied ATEX directives for equipment in potentially explosive atmospheres. This is accomplished by live wireless data transfer from the flux meters and utilizing standard ATEX certified components as building blocks. The system consists of both flux meters and a video recording system and has been in operation on the Equinor operated ship-shaped floating production, storage and offloading (FPSO) unit Norne in the Norwegian Sea since September 2017. Prior to full-scale deployment, a prototype was tested at the VELUX wind tunnel facility at variable wind speed and water injection rates. Along with accompanying environmental data and vessel motions, the spray measurements are providing a vital calibration data set for spray models on large ship-shaped offshore structures.
Language
English
Author(s)
Affiliation
  • Equinor
  • Det Norske Veritas AS
  • SINTEF Digital / Connectivity Technologies and Platforms
Year
2019
Published in
Proceedings - International Conference on Port and Ocean Engineering under Arctic Conditions
ISSN
0376-6756
Publisher
Port and Ocean Engineering under Arctic Conditions
Volume
2019-June