On April 20, 2010 the Deepwater Horizon drilling rig exploded about fifty miles off the coast of Louisiana in the Gulf of Mexico. A picture of the explosion can be seen in Figure 1 below. It sank two days later causing the pipe that connected the wellhead to the platform to bend. Four days after the explosion two leaks were discovered, almost a mile underwater, coming from the pipe (Corum et al.). About 185 million gallons of oil were spilled in the Gulf, making it the biggest oil spill in American history (Shapley). Some of the oil, which looks dull gray in the picture, can be seen in Figure 2 below.
Figure1: A photograph of the Deepwater Horizon explosion on April 20,2010.
(Credit: Gerald Herbert/ Associated Press)
Figure 2: An image from NASA showing the oil from the Deepwater Horizon spill.
(Credit: NASA, Goddard, MODIS Rapid Response Team)
Offshore drilling began in the late 1800’s, after people noticed that the wells near the ocean were the best oil producers
(NOIA). In 1891, the first offshore fresh water oil wells were drilled in Grand Lake St. Marys in Ohio. Then in 1896, the first offshore salt water oil wells were drilled in Summerland, California, as can be seen in Figure 3 below
(Wikipedia). In 1947, the Kerr-McGee Corporation drilled the first well from a fixed platform offshore out of sight of land
(NOIA). One of Kerr-McGee's out of sight of land rigs can be seen in Figure 4 below.
Figure 3: An image of the oil wells in Summerland, California pre-1906.
(Credit: G.H. Eldridge)
Figure 4: A photograph of Kerr-McGee Rig 16.
(Credit: Petrobras)
Oil can vary depending on the location, but classification of crude oils by location is not very useful. Instead, oil response workers classify oil based on toxicity, physical properties, and changes over time.
Class A oils are classified as “light, volatile oils.” They are usually fluid, clear, strong in odor, flammable, and evaporate at a high rate. These oils are able to spread fast on water and they are able to penetrate porous surfaces, such as dirt and sand. They are extremely toxic to humans, plants, and animals.
Class B oils are classified as being “non-sticky oils.” This means that the oils have a waxy/oily feel to them. These oils are less toxic and can stick better to surfaces than
Class A oils. When the temperature rises, these oils penetrate porous surfaces more often.
Figure 5: A photograph of the oil that spilled in the Gulf of Mexico just eight days after the spill.
(Credit: Chris Graythen/ Getty Images)
Figure 6: A photograph of the weathered oil found in the Gulf of Mexico.
(Credit: NOAA)
The evaporation of
Class B oils may lead to
Class C or
Class D oils.
Class D oils are classified as being “heavy, sticky oils.” These oils are very sticky and tarry. They are usually black or brown in color and are harder to remove from surfaces.
Class C oils do not penetrate porous surfaces as easily and often sink. These oils have a low toxicity, but if contaminated, animals can be smothered or drowned.
Class D oils are classified as being “non-fluid oils.” These oils are usually non-toxic and do not penetrate porous surfaces. They are usually black or dark brown and melt when heated, making them very hard to clean.
Class A includes most light crude oils,
Class C includes medium to heavy crude oils, and
Class D includes most heavy crude oils
. The weather and water temperature influence the behavior of the crude oils in the environment (EPA). Both Figure 5 and Figure 6 above show the spilled crude oil in the Gulf of Mexico, but unlike the image in Figure 5 that was take only eight days after the explosion, Figure 6 shows the oil about two months and ten days after.
Works Cited
"About NOIA." NOIA.org. National Ocean Industries Association. Web. 19 Oct. 2010.
<http://www.noia.org/website/article.asp?id=123>.
Baskin, Liza. "Weathered Oil" 2010. Photograph. NOAA.
Corum, Jonathan, Al Granberg, Mika Grondahl, Xaquin G.V., Haeyoun Park, Sergio Peçanha, and
Graham Roberts. "Efforts to Stop the Leaking Oil in the Gulf of Mexico." Nytimes.com. New York
Times. Web. 13 Sept. 2010. <http://www.nytimes.com/interactive/2010/05/25/us/20100525-
topkill-diagram.html>.
"Deepwater Horizon Oil Spill" 2010. Photograph. NASA. Connect-green.com. Connect Green. Web.
25 Oct. 2010. <http://www.connect-green.com/latest-nasa-satellite-image-of-gulf-of-mexico-
oil-spill/>.
Eldridge, G.H. "Oil Wells Just Offshore at Summerland, California" Photograph. Wikipedia.
Wikepedia The Free Encyclopedia. Web. 26 Oct. 2010. <http://en.wikipedia.org
/wiki/File:Oil_wells_just_offshore_at_Summerland,_California,_c.1915.jpg>.
Graythen, Chris. "Leaked Well Oil in the Gulf of Mexico" 2010. Photograph. Getty Images.
Theepochtimes.com. The Epoch Times. Web. 26 Oct. 2010. <http://www.theepochtimes.com
/n2/content/view/34441/>.
Herbert, Gerald. "Deepwater Horizon Explosion" 2010. Photograph. Associated Press. Nytimes.com.
New York Times. Web. 25 Oct. 2010. <http://www.nytimes.com/interactive/2010/05/25/us
/20100525-topkill-diagram.html>.
"Kerr McGee Rig 16" Photograph. Petrobras. Geoexpro.com. GEO ExPro. Web. 26 Oct. 2010.
<http://www.geoexpro.com/brazil/pioneering/>.
"Offshore Drilling." Wikipedia.com. Wikipedia, the Free Encyclopedia. Web. 19 Oct. 2010.
<http://en.wikipedia.org/wiki/Offshore_drilling>.
Shapley, Dan. "So How Big Was the BP Oil Spill?" The Daily Green. Web. 13 Sept. 2010.
<http://www.thedailygreen.com/environmental-news/latest/bp-oil-spill-size-0528>.
"Types of Crude Oil." EPA.gov. U.S. Environmental Protection Agency. Web. 13
Sept. 2010. <http://www.epa.gov/oem/content/learning/crude.htm>.
