The Deepwater Horizon Oil Spill

Tommy Mina
November 19, 2011

Submitted as coursework for PH240, Stanford University, Fall 2011

Fig. 1: Energy loss of oil spills in Gulf of Mexico.


A 2010 report on world energy by British Petroleum (BP) estimated that there were approximately 11.7 thousand million barrels of proved oil reserves located in the Gulf of Mexico, and 2979 thousand barrels were being produced daily. [1] On April 20, 2010, one of BP's exploratory wells in the gulf known as the Macondo Well blew out, killing 11 crew members on the Deepwater Horizon, the oil rig on the well site; the ensuing months were filled with a frenzy of various attempts to prevent the well from continuing to leak oil until a solution was finally found. [2] A comparison to previous oil spills in the Gulf of Mexico and an estimate of the total energy lost as a result of this disaster demonstrate the true magnitude of this event, even while ignoring the incredible environmental damage that came as a direct result.

The Spill

The failure of the Macondo well occurred as a result of many factors, culminating in a failure of the blowout preventer (BOP) installed on the Deepwater Horizon. [2] Due to a mechanical failure, a large flux of hydrocarbons had begun spilling from the Macondo reservoir into the well as it was being prepared for temporary abandonment; when rig officials discovered this, they attempted to divert the flow to a mud-gas separator on the rig. However, the separator was not designed to handle a flux of this size and quickly failed, sending a large gas plume above the rig floor. [2] This plume ignited and caused a massive explosion that left 11 crewmembers on the rig dead and many others injured. The BOP was designed to prevent such hydrocarbons from escaping the well by sealing it in the event of an emergency, but the hydrocarbon flow had forced the well pipe out of position, causing the fixed BOP to miss its target when it was activated by the crew. [3] Thus, following the initial explosion, oil began escaping from the well out into the Gulf of Mexico, continuing to do so until the well was finally contained 87 days later. [4]

Other Wells in the Gulf of Mexico

The Macondo Well blowout was not the first disaster of its kind in the Gulf of Mexico, but it certainly was the largest in magnitude. Another significant spill involving an exploratory well was the Ixtoc I in 1979. The blowout of this shallow exploratory well resulted in the release of approximately 140 million gallons (3.33 million barrels) of oil over the course of 9 months into the Gulf of Mexico, with a significant portion reaching the shores of Texas. [5] Many other accidents in the Gulf of Mexico were the result of problems during transportation, including 5.1 million gallons lost as a result of a fire on the Mega Borg tanker in 1990, and the total loss of approximately 10.7 million gallons when the Burmah Agate collided with the Mimosa freighter near the entrance to Galveston Harbor, Texas, in 1980 [6,7]. Each of these spills had effects not only in the Gulf, but also on the shore; given the proximity of each of these accidents to the coastline, large expanses were affected, with thousands of barrels washing up on shore.

Energy Lost

Estimates for the total amount of oil lost in the Macondo Well disaster range from about 4.5 million barrels to 4.9 million barrels, far greater than any other spill in the Gulf to this date. Given that each barrel contains 42 gallons of oil, this equates to approximately 189 million to 206 million gallons of oil lost. [2,8] This volume would fill half of the Alaskan Pipeline, which spans 800 miles, but is minimally significant when looking at the total Middle Eastern oil daily production, which is about 1,050 million gallons. [1,9] Assuming each barrel has an energy content of about 6.1 × 109 joules, this equates to a total of between 2.74 × 1016 and 3.0 × 1016 joules lost over the duration of the spill. If each barrel costs $50, then this equates to approximately $235 million in total revenue lost. However, in perspective, this is approximately a quarter of the United States' daily oil consumption, and one-twentieth of the world's daily oil use. [1]


This disaster resulted in countless environmental damage along with the loss of a significant amount of usable energy. As oil is still one of the dominant players in global energy production, its extraction should be done in a safe and controlled manner, with adequate technology in place to properly prevent any impending disaster. Though the amount of oil lost from the Macondo well was relatively small in comparison to the total world oil reserves and the amount of oil used daily throughout the world, its effects can be catastrophic on the world at large.

© Tommy Mina. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] "BP Statistical Review of World Energy," British Petroleum, June 2011.

[2] "Final Report on the Investigation of the Macondo Well Blowout," Center for Catastrophic Risk Management, University of California at Berkeley, 1 Mar 11.

[3] "Report Regarding the Causes of the April 20, 2010 Macondo Well Blowout," Bureau of Ocean Energy Management, Regulation and Enforcement, U.S. Department of the Interior, 14 Sep 11.

[4] J. W. Griggs, "BP Gulf of Mexico Oil Spill," Energy Law J. 32, 57 (2011).

[5] "Ixtoc Oil Spill Assessment - Final Report," ERCO Energy Resources Co., 19 Mar 82.

[6] R. Seymour and R. Geyer, "Fates and Effects of Oil Spills," Annu. Rev. Energy Environ, 17, 261 (1992).

[7] D. Etkin and J. Welch, "International Oil Spill Database: Trends in Oil Spill Volumes and Frequency," Oil Spill Intelligence Report, 1 Apr 97

[8] "Assessment of Flow Rate Estimates for the Deepwater Horizon / Macondo Well Oil Spill," U.S. Department of the Interior, March 2011.

[9] "The Facts: Trans-Alaska Pipeline System," Alyeska Pipeline Service Company, 2007.