ImpactWeather, Horizon Marine Continue to Support Atlantis Installation

ImpactWeather, Inc. and Horizon Marine, Inc. recently provided comprehensive weather and Loop/Eddy Current prediction support for the successful towout and installation of the Atlantis semisubmersible production platform, now moored at its permanent location in Green Canyon. Atlantis is an 89,000 metric ton semisubmersible platform and is the deepest moored production facility in the world. The project is operated by BP Exploration & Production Inc. and is a joint development of BP and BHP Billiton.

Intensive support was provided to support the towout "go" decision throughout the five-day tow across the Gulf of Mexico (approximately 400 miles from Corpus Christi to the platform’s destination) and throughout the three-week successful mooring operation in 7,000 feet of water. Similar support will continue throughout riser pullin and installation operations.

ImpactWeather provided a meteorologist onsite to assist with guidance and to consult directly with the project managers. According to ImpactWeather President Mark Chambers, “Weather at the Kiewit site, in the Corpus Christi Channel, and offshore was continuously monitored to determine if the necessary meteorological conditions for the sailaway would be met. These included sustained winds of less than 15 knots, seas of 3 feet or less at an offshore buoy just outside the channel and lack of a significant threat of strong wind gusts from thunderstorm activity. Another concern which had to be met before sailaway could occur was the possible threat of tropical storm development in the Gulf of Mexico. After a thorough analysis of tropical forecast data, it was determined that there would be at least a two-week weather window without a significant tropical weather threat to the Gulf of Mexico.” Several marine meteorologists continue to provide additional support to the project from ImpactWeather’s headquarters in Houston.

“Currents at the site were a significant factor influencing the ‘go/nogo’ decision,” according to Patrice Coholan, Horizon Marine’s Vice President Eddy Watch Operations. For monitoring and forecasting these currents, the project managers turned to Horizon for daily updates and forecasts. These reports were issued several months prior to the towout, during the five day journey across the Gulf and throughout the mooring operation.

The towout was delayed by high ocean currents at the Green Canyon site associated with “Yankee Eddy”, a major Loop Current Eddy impacting the Atlantis site with 3+ knot currents. These currents would have made the installation of mooring lines impossible, so operations were put on hold. In early August, Horizon Marine was able to predict a window of opportunity as Yankee Eddy and the Loop Current slowly translated to the west, and the forecast model placed the site deeper inside the system where currents were weaker. This forecast helped set the sailaway date for Atlantis to its location in Green Canyon. Subsequent updates, conference calls and reports continue to assist in the scheduling of tasks associated with the installation of the platform.

As a result of utilizing this intensive level of meteorological and loop/eddy current support, the operators had the information they needed to make the “go/nogo” decision with confidence and Atlantis is now safely and successfully moored at its final destination.

ImpactWeather, Inc. is a Houston-based private weather forecasting company specializing in marine weather forecasting. Operating 24/7, ImpactWeather’s focus is risk management and business continuity. Forecast types include storm management, offshore site forecasts, marine weather and severe weather alerts, route and tow forecasts, tropical weather support (including hurricane forecasts), and detailed winds/seas/swells forecasts provided by marine-dedicated meteorologists. ImpactWeather also provides proprietary graphics and text, regional threat assessments, and direct notification services (phone, email, PDA) to manufacturing, construction, petrochemical, government, military, transportation, and educational entities worldwide as well as live AM/FM radio weather forecasts.

Headquartered in Marion, Massachusetts, Horizon Marine, Inc. is an oceanographic services company that specializes in operational oceanography. They operate the Eddy Watch sm advisory service in the Gulf of Mexico and in the offshore Trinidad region. The Gulf program produces real-time ocean current maps with emphasis on the position and strength of the Loop Current and eddies which migrate throughout the basin. The emphasis in Trinidad is on the North Brazil Current and rings that shed from it and migrate across active lease blocks. Horizon Marine utilizes all available techniques including current meters, GPS/Argos drifting buoys, sea surface temperature satellite images, ocean color, altimetry, sea surface measurements, shipboard and aerial surveys, and numerical models. Clients for Eddy Watch include energy companies and government agencies. The company also specializes in oceanographic studies, hindcasts and sitespecific surveys.

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