On May 8, a large amount of leaked crude oil floated on the Gulf of Mexico. The oil spill in the Gulf of Mexico in late last month caused the region to face an unprecedented ecological disaster. At present, the US Coast Guard, government agencies, local residents and BP are trying their best to prevent the situation from getting worse. Xinhua News Agency/Reuters
On May 8, some ships carried out missions near a drilling platform in the Gulf of Mexico. Xinhua News Agency/Reuters
On May 8, in a hotel in New Orleans, Louisiana, USA, the staff were sorting out the hair stuffed into stockings. In order to reduce the damage to the ecological environment caused by the oil spill in the Gulf of Mexico, Louisiana has set up nine locations in the state to accept articles such as hair and fur products donated by the society, which can be thrown into the sea to absorb the leaked oil. Xinhua News Agency/AFP
BP's internal investigation shows that the explosion of Deepwater Horizon drilling platform in the Gulf of Mexico was caused by methane bubbles.
In addition, the last line of defense "blowout preventer" of oil spill has failed before.
Produce bubbles
As an employee of Deepwater Horizon, BP stepped up its investigation into the cause of the Deepwater Horizon explosion.
The Associated Press reported on the 8th that several business friends of Robert Beya, an engineering professor at the University of California, Berkeley, asked him for advice and gave him some investigation records of BP.
These records include two documents and a recording, and several drilling workers were questioned. Beya described the contents of the record in detail to the Associated Press reporter.
Beya is a member of the team responsible for oil pipeline safety in the National Academy of Engineering, and served as a risk assessment consultant for BP in the 1990s.
According to these records, Beya restored the process before and after the explosion.
Workers set and tested a cement seal at the bottom of the well, then reduced the internal pressure of the drill pipe and tried to set another cement seal. At this time, the chemical reaction caused by setting the seal generates heat, which leads to the formation of methane bubbles, thus leading to the destruction of this seal.
Methane is usually crystallized at the bottom of the sea. Methane crystals are often encountered during the operation of deep-sea drilling platforms.
This methane bubble rose from the high pressure at the bottom of the drill pipe to the low pressure, breaking through several safety barriers.
"A small bubble will become a quite big bubble," Beya said. "The inflated bubble is like a cannon, blowing into your face."
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"gas cloud" hood top
Beya said that the incident occurred on April 20, when workers on the drilling platform observed that the drill pipe suddenly burst, and then gas and crude oil emerged.
The gas rushed to a room with flammable materials, where the first explosion occurred. "Then there was a series of explosions, which ignited the rising crude oil," he said.
An inquiry record shows that a "gas cloud" rose at that time and covered the "Deepwater Horizon". The large engine on the drill floor exploded immediately. Respondents said that the engine exploded and ignited the rig floor, "there was fire everywhere".
About 36 hours after the explosion, the Deepwater Horizon sank into the Gulf of Mexico. Some managers of BP were injured, and nine drilling workers and two engineers died.
"It must be like hell," said Beya. The 73-year-old oil industry "veteran" cried here. He said that this is "tears of disappointment and anger."
BP spokesman John Currie refused to talk about the cause of the accident on the evening of the 7th. "We are waiting for a full investigation to find out all the facts."
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Valve failure
After the Deepwater Horizon sank, a large amount of oil leaked, threatening the surrounding ecological environment. The "blowout preventer" equipped with the drilling platform has also become the focus of investigation.
A "blowout preventer" is as big as a double-decker bus and weighs 290 tons. As the last barrier to prevent oil leakage, the "blowout preventer" is installed at the wellhead to close the oil pipe after oil leakage. However, the blowout preventer of Deepwater Horizon did not start normally.
Deepwater Horizon is equipped with an automatic backup system. This system should activate the "blowout preventer" when the worker failed to activate it, but it didn't work at that time.
After the incident, BP tried to start the "blowout preventer" with the help of the underwater robot, but failed.
The Associated Press reported that since the federal government regulators relaxed equipment testing, the "blowout preventers" of several drilling platforms have failed to play their due roles for several years.
The accident report received by the Bureau of Mineral Resources Management of the Ministry of Interior shows that at least 14 accidents are related to the "blowout preventer". Most of these accidents occurred after 2004.
Federal regulators say they will check whether the "blowout preventers" of several drilling platforms are reliable. Congress intends to hold a hearing on the reliability of the blowout preventer.
"This kind of safety valve is not very safe," Senator Maria Cantwell said. It is well known in the industry that the "blowout preventer" sometimes fails, but it is lucky to use it.