THE 2010 OIL SPILL IN THE GULF OF MEXICO - FLOW-RATE ESTIMATION BASED ON SATELLITE-IMAGES ANALYSIS

摘要

The Deep-water Horizon Mobile Offshore Drilling Unit (MODU) was one of several classes of floatable drilling machines. The explosion on April 20, 2010 led to the worst ecological disaster with regard to oil spills in the USA. The objective of this paper is to develop a logical and independent estimate of the oil flow rate into the Gulf of Mexico produced by the rupture in this rig. We employed the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) satellite photographs [1] starting from the days immediately following the disaster to determine the size and intensity of the oil spill. From these images, we obtained the surface area of the oil spill and calculated the oil flow rate by two different methods based on contrasting luminance within the area. The first assumes a constant thickness for the total area with upper and lower bounds for the thickness. The second method separates the spill area into different patches, based on the luminance levels of each. It was found that the probability density function (PDF) of the luminance plots typically showed some natural grouping, allowing patches to be defined. Each patch maps to a specific thickness and the result of the addition of all the patches provides a more accurate average thickness of the spill. With the assumption that evaporation and other loss amounted to 40% of the spill, we obtained, as a result of this analysis procedure, a minimum flow rate of 9,300 barrels per day and a maximum of 93,000 barrels per day using the first method. A value of 51,200 barrels per day was obtained using the method based on patch separation. This latter estimate was a reasonable value obtained based on this relatively simple method but with no details presented in an Extended Abstract in OMAE2012 [4]. It is remarkably consistent with the "official US-Govt. estimates" of [2, 3].