The following is a timeline of the Deepwater Horizon oil spill (also referred to as the BP oil spill, the Gulf of Mexico oil spill or the Macondo blowout). It was a massive oil spill in the Gulf of Mexico, the largest offshore spill in U.S. history. It was a result of the well blowout that began with the Deepwater Horizon drilling rig explosion on April 20, 2010.
Background
2008 March 2008 – The mineral rights to drill for oil at the Macondo well, located in Mississippi Canyon Block 252 in the United States sector of the Gulf of Mexico about off the Louisiana coast, were purchased by BP at the Minerals Management Service's (MMS) Lease Sale No. 206, held in New Orleans.
2009 February – BP files a 52-page exploration and environmental impact plan for the Macondo well with the MMS. The plan stated that it was "unlikely that an accidental surface or subsurface oil spill would occur from the proposed activities". In the event an accident did take place the plan stated that due to the well being from shore and the response capabilities that would be implemented, no significant adverse impacts would be expected. April 6 – The Department of the Interior exempted BP's Gulf of Mexico drilling operation from a detailed environmental impact study after concluding that a massive oil spill was unlikely. June 22 – Mark E. Hafle, a senior drilling engineer at BP, warns that the metal casing for the blowout preventer might collapse under high pressure. October 7 – The Transocean Marianas semi-submersible rig begins drilling the Macondo well. November 9 – Hurricane Ida damages Transocean Marianas enough that it has to be replaced.
2010 events
February February 15, 2010 – Deepwater Horizon drilling rig, owned by Transocean, begins drilling on the Macondo Prospect. The planned well was to be drilled to below sea level, and was to be plugged and suspended for subsequent completion as a subsea producer.
March March 8 – Target date for the completion of the well which had been budgeted to cost $96 million. March 17 – BP Chief Tony Hayward sells one third of his BP stock (223,288 shares). Closing BP price on March 17 on the New York Stock Exchange is 58.15. March – An accident damages a gasket on the blowout preventer on the rig.
April
April 1 – Halliburton employee Marvin Volek warns that BP's use of cement "was against our best practices." April 6 – MMS issues permit to BP for the well with the notation, "Exercise caution while drilling due to indications of shallow gas and possible water flow." April 9 – BP drills last section with the wellbore below sea level but the last needs casing. Halliburton recommends liner/tieback casing that will provide 4 redundant barriers to flow. BP chooses to do a single liner with fewer barriers that is faster to install and cheaper ($7 to $10 million). April 14 – Brian Morel, a BP drilling engineer, emails a colleague "this has been a nightmare well which has everyone all over the place." April 15 – Morel informs Halliburton executive Jesse Gagliano that they plan to use 6 centralizers. Gagliano says they should use 21. Morel replies in an email, "it's too late to get any more product on the rig, our only option is to rearrange placement of these centralizers." Gagliano also recommends to circulate the drilling mud from the bottom of the well all the way up to the surface to remove gas pockets and debris which can contaminate the cement, saying in an email, "at least circulate one bottoms up on the well before doing a cement job." Despite this recommendation, BP cycles only of mud, a fraction of the total mud used in the well. April 15 – MMS approves amended permit for BP to use a single liner with fewer barriers. April 16 – Brett Cocales, BP's Operations Drilling Engineer, emails drilling engineer Brian Morel confirming the 6 centralizer approach, saying six should be adequate to obtain a proper cement seal in the well. "Who cares, it's done, end of story, will probably be fine and we'll get a good cement job," he wrote, according to a copy of the e-mail cited in court papers. (Halliburton was the cement provider.) April 17 – Deepwater Horizon completes its drilling and the well is being prepared to be cemented so that another rig will retrieve the oil. The blowout preventer is tested and found to be "functional." Gagliano now reports that using only 6 centralizers "would likely produce channeling and a failure of the cement job." April 18 – Gagliano's report says "well is considered to have a severe gas flow problem." Schlumberger flies a crew to conduct a cement bond log to determine whether the cement has bonded to the casing and surrounding formations. It is required in rules. April 19 – Halliburton completes cementing of the final production liner string. April 20 – 7 am – BP cancels a recommended cement bond log test. Conducting the test would have taken 9–12 hours and $128,000. By canceling the cement test BP paid only $10,000. Crew leaves on 11:15 am flight. BP officials gather on the platform to celebrate seven years without an injury on the rig. The planned moving of the Deepwater Horizon to another location was 43 days past due and the delay had cost BP $21 million.
9:49 pm (CDT) – Andrea Fleytas had been monitoring the dynamic positioning system on the bridge of the Horizon when she felt a jolt. Before she could make sense of it – a rig shaking shock that came out of nowhere – magenta warnings began flashing on her screen. Magenta meant the most dangerous level of combustible gas intrusion.Fire on the Horizon – John Konrad & Tom Shroder pages 209–210.
9:56 pm CDT – Gas from the wellbore erupts through the rig floor and then catches fire. The explosion kills 11 platform workers and injures 17 others; another 98 people survive without serious physical injury.
April 21 – Coast Guard rear admiral Mary Landry is named Federal On Scene Coordinator. Coast Guard log reports "Potential environmental threat is 700,000 gallons of diesel on board the Deepwater Horizon and estimated potential of 8,000 barrels per day of crude oil, if the well were to completely blowout. Most of the current pollution has been mitigated by the fire. There is some surface sheening extending up to 2 miles from the source." The log also reports that two attempts to shut the BOP using an ROV have failed. April 22 – Rig sinks. CNN quote Coast Guard Petty Officer Ashley Butler as saying that "oil was leaking from the rig at the rate of about of crude per day." of dispersants are pre-authorized by the United States Environmental Protection Agency (EPA) and placed in position even though there is no sign of a leak. Three Norwegian crews from Ocean Intervention III from Oceaneering International, Skandi Neptune from DOF ASA, and Boa Sub C (from Boa International) begin using remotely operated underwater vehicles (ROV) to map the seabed and assess the damage to the wreck. The crews report "large amounts of oil that flowed out."De må ha visst at lekkasjen var mye større – Dagbladot.no – May 28, 2010 – Retrieved June 17, 2010 (translate Norweignian to English) April 23 – Coast Guard rear adm. Mary Landry tells CBS "At this time, there is no crude emanating from that wellhead at the ocean surface, er, at the ocean floor...There is not oil emanating from the riser either." Unified Command begins operating out of the Royal Dutch Shell Training and Conference Center in Robert, Louisiana. Search and rescue suspended at 5 pm. Eleven of the 126 people on the rig have perished. Coast Guard log reports, "BP will establish an ICP at Houma, Louisiana today to monitor the response and prepare for potential release estimated potential of 64,000- 110,000 bbls (2 ,688,000- 4,620,000 gal) per day of crude oil if the well were to completely blowout." April 24 – In accordance with the existing in situ burn plans, the OSC determined in situ burning was a viable response method for several reasons. First, weather and sea-state did not allow continuous skimming and alternatives were needed. Second, skimmers and dispersants could not completely remove the oil being released from the well. Finally, the OSC determined in situ burning (ISB) was a safe and effective way to remove large volumes of oil from the ocean surface, based on data for in situ burns from previous spills. BP reports a leak a day. The DeepWaterHorizonResponse.com domain is registered for one year by PIER Systems in Bellingham, Washington to be used by the United States Coast Guard and other reporting agencies. Price of a barrel of oil (West Texas Intermediate – Cushing, Oklahoma) is $84.34.
April 25 – Oil sheen seen covering and is south of Mississippi and Alabama coastlines and was from the ecologically sensitive Chandeleur Islands. BP begins process to establish two relief wells. April 26 – Oil reported southeast of Louisiana. Booms set up to keep oil from washing ashore. A huge containment chamber is moved to Superior Energy Services subsidiary Wild Well Control in Port Fourchon, Louisiana. BP closing stock price 57.91 Coast Guard log reports "attempts to actuate the blow preventer (BOP) middle rams and blind shears were ineffective due to a hydraulic leak on the valve. Repairs are being worked overnight. The well head continues to discharge approximately 1,000 barrels/day. April 27 – Slick grows to across and from Louisiana coast. April 28 – National Oceanic and Atmospheric Administration estimated that the leak was likely a day, five times larger than initially estimated by BP. BP announces controlled test to burn oil off the surface was successful. Oil is east of the mouth of the Mississippi River. MMS postpones 2010 Offshore Industry Safety Awards scheduled to be May 3. April 29 – Louisiana Governor Bobby Jindal declares a state of emergency. of containment booms were deployed along the coast. By the next day, this nearly doubled to of deployed booms, with an additional staged or being deployed. April 30 – Oil washes ashore at Venice, Louisiana. President Barack Obama halts new offshore drilling unless safeguards are in place. – Coast Guard issues subpoena to Transocean "to maintain the blowout preventer and to not allow anyone or anything to tamper with it" without the Guard's permission. EPA establishes its website for its response. Sanford Bernstein estimates capping the leaks and cleaning up the spill may cost $12.5 billion. On April 30, the United States House Committee on Energy and Commerce asked Halliburton to brief it as well as provide any documents it might have related to its work on the Macondo well. April 30 – Florida Governor Charlie Crist declares a state of emergency for 6 counties.
May
May 2 – President Obama meets with fishermen and Coast Guard in Venice, Louisiana. Oil discovered in the South Pass.Deepwater Horizon Rig Disaster – Time – wsj.com – Retrieved June 3, 2010. Transocean's Development Driller III starts drilling a first relief well. May 3 – Shares of Nalco Holding Company jump 18% in one day after it is revealed that its dispersant products are being used for the cleanup. May 3 – Florida Governor Charlie Crist extends emergency declaration to 19 counties. May 5 – BP announces that the smallest of three known leaks had been capped allowing the repair group to focus their efforts on the remaining leaks. May 6 – Oil sheen discovered in south end of Chandeleur Chain. May 7 – A containment dome is lowered over the largest of the well leaks and pipe the oil to a storage vessel on the surface. May 7 – Florida enters into an initial agreement with BP, providing for $25 million in emergency funding. Further grants by BP follow over time. May 8 – BP reports that methane is freezing at the top of the dome making it ineffective. May 9 – Tar balls reported on Dauphin Island in Alabama.