Sunday, June 27, 2010

Timeline Of BP Oil Spill In The Gulf Of Mexico


Also referred to as the BP oil spill, the Gulf of Mexico oil spill or the Macondo blowout.

Interesting read from Wiki. and it continues into June 2010.
See the interactive map.


Events leading to the spill
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 41 miles (66 km) off the Louisiana coast, were purchased by BP at the Minerals Management Service's (MMS) Lease Sale #206, held in New Orleans.[6]

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 48 miles (77 km) from shore and the response capabilities that would be implemented, no significant adverse impacts would be expected. 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, 2009 - 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
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 18,000 feet (5,500 m) 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 - An accident damages a gasket on the blowout preventer on the rig.

April
Fighting the fire on April 21

* 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 18,360 feet (5,600 m) below sea level but the last 1,192 feet (363 m) need 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 air 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 261 barrels (41.5 m3) 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 Morel confirming the 6 centralizer approach.

* 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 reports that using only 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 casing string.

Destruction of the Deepwater Horizon

* 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.

*

* 9:45 p.m. CDT - Gas, oil and concrete from the Deepwater Horizon explode up the wellbore onto the deck and then catches fire. The explosion kills 11 platform workers and injures 17 others; another 98 people survive without serious physical injury.[21]

* April 21 Coast Guard rear admiral Mary Landry named Federal On Scene Coordinator.[22] 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.[23][24]

* April 22 10:21 am - Rig sinks. CNN quote Coast Guard Petty Officer Ashley Butler as saying that "oil was leaking from the rig at the rate of about 8,000 barrels (340,000 US gallons; 1,300 cubic metres) of crude per day." 100,000 US gallons (380,000 litres) 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 Norweigian 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."


Read the rest.

No comments: