What caused the 2010 BP gulf oil spill?

Answer 1

The BP oil disaster in the Gulf of Mexico is primarily the direct result of a well blowout. What exactly caused the blowout is still not clear, but is most often described as a series of failures, all of which may not yet have been identified. BP has stated that the catastrophe occurred because a series of measures, that should have prevented a blowout, failed.

The blowout (uncontrolled high pressure flow of oil and gases), occurred at approximately 9:51 pm on April 20, 2010, followed by fire and explosions on the rig floor (causes not yet definitive), and following that, on April 21, the BP Deepwater Horizon rig sank.

As a well is drilled, precautions are taken so fluids from formation can not enter the well. There were no problems several days earlier when the rig drilled through the productive zone. They had heavy drilling "mud" in the well that kept the fluids from entering the well-bore.

After drilling through the productive zone and then a further few hundred feet below it, they cemented in a liner (production tubing). Haliburton, a contractor working on the well, had finished cementing in a production casing when abnormal pressures were detected in the marine riser.

As they were waiting for the cement to harden, they circulated in lighter weight fresh sea water where the heavy mud had been, and hours later, there was an influx of hydrocarbons (Methane) coming either from the bottom of the well, through the float collar, or at the top of the well. It was a known "gassy" reservoir of oil. This methane was able to push through the sea water where the heavy mud had been and rushed out of the drill pipe, through the seal assembly.

The "blowout preventer" (BOP) failed to actuate and the Emergency Disconnect System, designed to unlatch the riser from the BOP, also failed when it encountered the pressures of over 115,000 psi.

Oil continued to blowout and land on the rig. Fire is presumed to have begun in the engine room and, fueled by the oil on the rig, went out of control. 11 people working on the rig were killed, and the survivors were unable to stop the fire.

Because of the fire or the explosion, a wellhead was damaged, the drilling rig collapsed, breaking the piping that connected the drill to the well approximately 5000 ft below sea level. This allowed oil to begin to gush directly into the ocean. The fail safes that are supposed to protect the environment and people in this type of situation failed, or were inadequate under the deep well conditions.

Long Term causes

Poor US laws regulating off shore drilling, especially in very deep locations, and complete failure of the Federal agency responsible for inspection and enforcing those laws, Minerals Management Service (MMS), also contributed. The technology for drilling as deeply as this well is not well proven, and what safety measures could have helped either failed, or were not in place.

Self regulation of the industry, allowed by MMS is another factor. Operating in waters this deep is obviously dangerous and full of risk. Current regulation could not prevent this or similar disasters indicating a strong need for regulatory reform and oversight.

Until more information is revealed, the full causes are still speculative. Many more details should be available after a full inquiry is made.

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