Story behind Deepwater Horizon Oil Spill

Deepwater Horizon oil spill, also called the Gulf of Mexico oil spill, the largest marine oil spill in history, caused by the April 20, 2010, explosion on the Deepwater Horizon oil rig located in the Gulf of Mexico, approximately 41 miles (66 km) off the coast of Louisiana—and its subsequent sinking on April 22.

Deepwater Horizon Oil Rig

Construction of Oil Rig:

Deepwater Horizon was built for R&B Falcon by Hyundai Heavy Industries in Ulsan, South Korea. Construction started in December 1998, the keel was laid on 21 March 2000, and the rig was delivered on 23 February 2001, after the acquisition of R&B Falcon by Transocean. Until 29 December 2004, the rig was registered in the Republic of Panama. The rig was leased to BP on a 3-year contract for deployment in the Gulf of Mexico following construction. The lease was renewed in 2004 for a year, 2005 for 5 years, and 2009 for 3 years covering 2010 to 2013.

What Happened on 20 April 2020:

In February 2010, Deepwater Horizon commenced drilling an exploratory well at the Macondo Prospect, about 41 miles (66 km) off the southeast coast of Louisiana, at a water depth of approximately 5,000 feet (1,500 m). 

At 7:45 p.m. CDT (Central Daylight Time) on 20 April 2010, during the final phases of drilling the exploratory well at Macondo, a geyser of seawater erupted from the marine riser onto the rig, shooting 70 m into the air. This was soon followed by the eruption of a slushy combination of drilling mud, methane gas, and water. The gas component of the slushy material quickly transitioned into a fully gaseous state and then ignited into a series of explosions and then a firestorm. An attempt was made to activate the blowout preventer, but it failed. The final defence to prevent an oil spill, a device is known as a blind shear ram, was activated but failed to plug the well. 

Eleven workers were presumed killed in the initial explosion. The rig was evacuated, with 17 injured workers airlifted to medical facilities. After approximately 36 hours, Deepwater Horizon sank on 22 April 2010. The remains of the rig were located resting on the seafloor approximately 1,500 m deep at that location, and about 400 m northwest of the well.

The extent of Oil Spill: 

The oil leak was discovered on the afternoon of 22 April 2010 when a large oil slick began to spread at the former rig site. The oil flowed for 87 days. BP originally estimated a flow rate of 1,000 to 5,000 barrels/day (160 to 790 cubic meters/day). The total estimated volume of leaked oil approximated 4.9 Million barrels (780,000 m3) with plus or minus 10% uncertainty, including oil that was collected, making it the world's largest accidental spill. According to the satellite images, the spill directly affected 70,000 square miles (180,000 square km) of the ocean, which is comparable to the size of Oklahoma.

How the Oil Spill is arrested:

First, BP unsuccessfully attempted to close the blowout preventer valves on the wellhead with remotely operated underwater vehicles. Next, it placed a 125-tonne (280,000 lb) containment dome over the largest leak and piped the oil to a storage vessel. While this technique had worked in shallower water, it failed here when gas combined with cold water to form methane hydrate crystals that blocked the opening at the top of the dome. Pumping heavy drilling fluids into the blowout preventer to restrict the flow of oil before sealing it permanently with cement ("top kill") also failed. 

BP then inserted a riser insertion tube into the pipe and a stopper-like washer around the tube plugged at the end of the riser and diverted the flow into the insertion tube. The collected gas was flared and oil stored onboard the drillship Discoverer Enterprise. Before the tube was removed, it collected 924,000 US gal (22,000 barrels; 3,500 cubics meters) of oil. BP removed the damaged drilling riser from the top of the blowout preventer and covered the pipe with the cap. The United States government's estimates suggested the cap and other equipment were capturing less than half of the leaking oil. 

On 10 July, the containment cap was removed to replace it with a better-fitting cap. A final device was created to attach a chamber of larger diameter than the flowing pipe with a flange that bolted to the top of the blowout preventer and a manual valve set to close off the flow once attached. On 15 July, the device was secured and time was taken to close the valves to ensure the attachment was under increasing pressure until the valves were closed completing the temporary measures.

Containment & Removal of Oil Spill:

The fundamental strategies for addressing the spill were containment, dispersal and removal. In summer 2010, approximately 47,000 people and 7,000 vessels were involved in the project. Containment booms stretching over 4,200,000 ft (1,300 km) were deployed, either to corral the oil or as barriers to protect marshes, mangroves, shrimp/crab/oyster ranches or other ecologically sensitive areas. Booms extend 18–48 in (0.46–1.22 m) above and below the water surface and were effective only in relatively calm and slow-moving waters. Including one-time use sorbent booms, a total of 13,300,000 ft (4,100 km) of booms were deployed. 

On the most demanding day, 47,849 people were assigned on the response works and over 6,000 Marine vessels, 82 helicopters, and 20 fixed-wing aircraft were involved. Oil was collected from water by using skimmers. In total 2,063 various skimmers were used. For offshore, more than 60 open-water skimmers were deployed, including 12 purpose-built vehicles. Many large-scale skimmers exceeded the limit. Due to the use of Corexit (oil dispersant) the oil was too dispersed to collect oil. In mid-June 2010, BP ordered 32 machines that separate oil and water, with each machine capable of extracting up to 320 m3 of oil per day. After one week of testing, BP began to proceed and by 28 June, had removed 141,000 m3 of oil.

Environmental Damage:

Thousands of birds, mammals, and sea turtles were plastered with leaked oil. A December 2013 study of living dolphins in Barataria Bay, Louisiana, found that roughly half were extremely sick; many suffered from lung and adrenal disorders known to be linked to oil exposure. Some 1,400 whales and dolphins had been found stranded by the end of 2015, a figure representing only a tiny percentage of the animals affected. 

Birds were particularly vulnerable to the oil’s effects, and many perished—from ingesting oil as they tried to clean themselves or because the substance interfered with their ability to regulate their body temperatures. Animals that were found alive in the wake of the spill were transported to rehabilitation centres and, after being cleaned and medically evaluated, were released into oil-free areas. 

Movie Behind this Accident:

This huge disaster has been filmed on the same name as Deepwater Horizon that was directed by Peter Berg. Mark Wahlberg played the lead role and the film was released in the year 2016. This movie came out as one of the biggest blockbuster hits of the year. This movie can be viewed on Amazon Prime or Netflix.

You can view the movie Trailer here: