When Mother Nature Smiles - Multi-year Analysis of Currents at the Macondo Well Site

Abstract

Abstract Contrary to popular belief, the Deepwater Horizon (DWH) blowout and oil spill could have been far more environmentally and economically catastrophic. Relatively benign metocean conditions persisted in the Gulf of Mexico during the spill response efforts at the Macondo site. Statistical evidence indicates that metocean conditions could have been far worse, making the response efforts significantly more challenging and the economical repercussions orders of magnitude greater. Analysis of historical data and statistical trends over the past 26 years enumerates 22 separate incursions of the Loop Current or Loop Current Eddy into northern Mississippi Canyon. Such conditions can vastly complicate the scale of response efforts. Here we are presenting the possible impacts of worst-case environmental scenarios on response efforts at the Macondo site and the potential repercussions of strong Loop Current events during the oil spill. This study will help outline effective metocean risk management strategies for deepwater operators to mitigate the effects of oil spills in the future. Introduction The activities of the offshore oil & gas industry in the Gulf of Mexico (GOM) have intensified and extended farther offshore in recent decades, creating new challenges for marine resource and environmental management. The occurrence of oil spills in such an environment is fundamentally a matter of probability. Although not the first, the Deepwater Horizon oil spill has proved to be the largest and most catastrophic in U.S. waters. The semi-submersible offshore drilling rig was operating in 1500m of water when it experienced a fatal explosion on 20 April 2010. The explosion resulted in the prolonged expulsion of oil from the sea floor and the broken riser before the well was finally capped on 15 July. Final estimates of the oil released into the water column range from 798,000 gallons/day (USGS, 2010) to 4 million gallons/day (BP maximum estimate, 20 June 2010). Early reports on 23 April indicated that the oil spill had already formed a surface slick 1.6 km wide by 8 km long. By 25 April aerial surveys reported sheen spreading over a surface area of 32 km2 (NOAA 2010). Within two days, the edge of this slick approached within 40 km of coastal Louisiana. Response efforts to contain, collect, disperse, or burn the surface oil slick and landed oil fraction involved the efforts of some 48,000 people over the Gulf coast region, with the majority along the coastlines and shelf waters of Louisiana, Mississippi, and Alabama and the northwestern coast of Florida. Damage assessment and recovery effort continue to this day.