Mauritania, and the whole west coast of Africa as far south as Angola, is subjected to sudden and damaging squalls. These are high winds resulting from collapsing thunderstorms that bring with them heavy rain and sometimes sandstorms.
“Our role was to ensure safe operations of a deep sea drilling vessel, drilling in extremely shallow water of about 300m,” explains Forecast Manager, Trevor Pitt. “In such water depths there is very little flexibility for the marine riser. Had strong winds shifted the vessel more than 5m, expensive damage would have been caused to the riser and the subsea assets. One way of avoiding the damage was to withdraw the drill string when a squall was predicted. However, the financial implications of this action every time a squall was expected would have been extensive, and it was therefore essential to monitor the squall’s movement and determine its proximity and impending danger to the vessel.”
“We were called in to solve this challenge, by providing on-board advice and assistance in establishing a squall warning system. This worked extremely well. The success led to predicting and monitoring five squalls during the 2-week duration of the project.”
Operating 24-hours a day, every day of the year, the Fugro GEOS’ Weather Forecast Centre, in Wallingford in the UK, provides clients with detailed meteorological information; it is staffed with experienced forecasters who prepare detailed and easy-to-understand weather forecasts for a wide variety of applications.
They were on hand to assist throughout the Mauritanian project by monitoring every image of cloud structure over the relevant area at heights ranging from 10,000 to 60,000ft and assessing the risk remotely whilst Trevor Pitt, onboard the vessel, experienced the squalls at first hand, ensuring that the advice being given to the client from Wallingford was timely and accurate.
“We needed to be on the vessel on this occasion because of the shallow location and to assist the client in managing their situation safely,” explains Trevor Pitt
“The aim was to establish a system that provided six hours’ warning of a serious squall. It was essential that we kept a 24/7 watch on the weather and naturally there were times when responsibility passed from me back to the team in Wallingford. We were able to set up a three tiered warning system – Green for ‘keep drilling’; Amber for ‘risk that we will have to stopdrilling’; and Red for ‘stop drilling’. The system worked well and is ideal for projects of this nature especially West African drilling rigs and FPSOs that are affected by squalls.”
“We are confident that from Wallingford we can advise operators and drilling contractors the whole length of West Africa about the squall procedure steps they should take, and when to implement them. Our presence on the scene would only be essential for very weather sensitive tasks such as installing an FPSO or where rigs are operating very close to their limits.”
Further information on all aspects of the Fugro GEOS Weather Forecasting Service is available at www.geos.com and from firstname.lastname@example.org The service enables clients to receive instant up-to-date weather forecasts for any location either onshore or offshore by telephone or e-mail request. Fugro GEOS’ service enables clients to speak directly to a forecaster who has the latest information at his fingertips and can discuss specific requirements. The service is available 24-hours a day, every day of the year.