ImpactWeather Product Manager and Meteorologist Bob Weinzapfel guest-posts today about activity at last week’s Offshore Symposium in Houston hosted by the Society of Naval Architects and Marine Engineers (SNAME). The study described and similar studies have an incalculable, positive impact on preserving lives and assets relevant to severe weather.
On Thursday, February 2nd, Dr. Momen Wishahy of Transocean presented a study about “dynamic positioning (DP) vessels” evading hurricanes in the Gulf of Mexico. About 200 SNAME members listened carefully as Dr. Wishahy explained the simulation methodology and results that ImpactWeather conducted for Transocean.
Transocean operates a fleet of ships and semi-submersibles that drill or produce oil wells in deep water. Unlike fixed platforms in shallow water, they must secure the well on the seabed floor and move out of the path of a hurricane when threatened.
In the study, virtual DP vessels were placed on a dense grid covering the Gulf of Mexico and each vessel was programmed to evade historical hurricane forecasts from 37 separate hurricanes. Vessels with different traveling speeds and sensitivities to wind and wave conditions were analyzed, and each virtual evasion attempt was considered successful when the wind and wave conditions remained below certain thresholds. Statistics of all the evasions were generated and analyzed in several different ways.
The study yielded several important results:
- Perhaps not surprisingly, southwesterly evasions were more successful when starting to the left of the forecast track and easterly evasions are best when starting to right of the track
- Vessels should leave earlier to avoid the larger swath of high wind/wave conditions with the largest hurricanes (Rita, Katrina, Ike, Ivan, etc.).
- The starting position of generally 0 to 75 nautical miles to the right of the forecast track is a tough spot to start. Success rates are worse here and it can be hard to decide which direction to go.
- Although Forecast track errors have evolved to be much better over the last 20 years but can still lead to a troublesome situation if the vessel is too slow or leaves too late.
The results provide a statistical basis to help DP vessel operators determine how to best minimize the risk associated with avoiding hurricanes. They quantify how vessels starting in a similar situation (say 48 hours from the storm center and 25 nautical miles to the right of the forecast track) faired in the past going in either a southwesterly or easterly direction and can help captains and tactical decision–makers respond to future hurricane threats.
If you have questions about this study, feel free to contact me, Bob Weinzapfel at email@example.com.
DP Vessel Hurricane Evasions in the Gulf of Mexico
Authors: Bob Weinzapfel, Dante Diaz, Devin Eyre, Momen Wishahy
Presented by Momen Wishahy
The 17th Offshore Symposium – Pushing Boundaries in the Global Industry
Houston, February 2, 2012
Sponsored by Texas Section of the SNAME
In addition to providing excellent forecast and notification services to clients, ImpactWeather works with its clients to better understand how they’re affected by the weather and determine the best way we can help mitigate risks. This helps keep our clients’ employees and assets safer and allow them to operate more effectively with less downtime which can make a big impact on any business’ bottom line. ImpactWeather can conduct research such as this to help gain a better understanding of exactly how weather affects a certain client’s business. We can also use the results to tailor custom forecasting and notification services that optimally fit within your business processes.