Deepwater oil-spill modeling for assessing environmental impacts

Oil and gas activities in deepwater (areas deeper than 340 meters) have proceeded at an unprecedented rate, and have led to concerns about oil released by accidents near the seafloor. Oil and natural gas releases in deep water behave much differently than in shallow water. This is primarily because of the density stratification, high pressures, and low temperatures found in deep water. Some physical and chemical changes that occur in deepwater environments may significantly reduce the buoyancy of the plume and keep large amounts of the oil submerged for an extended time. This has significant implications for environmental impact assessment, oil-spill cleanup, contingency planning, and source tracing. The Minerals Management Service (MMS) performs an oil-spill risk analysis (OSRA) to estimate the probability of oil spills occurring and the risks of contact to environment resources. The Clarkson Deepwater Oil and Gas Blowout Model (CDOG model) is a jet/plume model that simulates the behavior of oil and gas accidentally released in deepwater areas. The OSRA model and the CDOG model are used to estimate the contact of deepwater oil spills to the environmental resources. Real-time current data from Acoustic Doppler Current Profilers (ADCP's) deployed on offshore platforms are used to drive the models. Preliminary results indicate that the OSRA model and the CDOG model can provide important information on the behavior of oil spills in the deep water. Ultimately, this information will be used in the pertinent environmental impact statements and in the development of deepwater oil-spill response plans.