Ixtoc I

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Map: Mexico
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Ixtoc I​
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Mexico

Ixtoc I was commissioned by the Mexican oil company PEMEX in the southern Gulf of Mexico in the Bay of Campeche down accommodated exploration sbohrung. The drilling company had a serious accident on June 3, 1979, causing the largest oil spill ever; the later oil spill on the Persian Gulf of 1990/1991 and the oil spill of 2010 due to the explosion of the exploration oil drilling platform Deepwater Horizon were larger . Crude oil leaked uncontrollably for over nine months until the well was closed on March 23, 1980.

The misfortune

The accident site at the Ixtoc I oil well

The Sedco 135 oil drilling platform used for drilling in 50 meters of water was operated by the Schlumberger subsidiary Sedco, which later merged into Transocean , the operator of the Deepwater Horizon drilling platform that was damaged in 2010. The drilling fluid failed at a depth of around 3000 meters . The increased hydrostatic pressure resulting from the high specific weight of the drilling fluid prevents the penetration of fluids, which are also under high pressure, from the rock into the borehole during normal operation. From the Ixtoc I well, gas and crude oil leaked out of control (so-called blowout ), which ignited and on June 3, 1979 destroyed the oil platform.

Oil slick around the exit point

In contrast to tanker accidents, the oil did not reach the open sea within a short time, but over a period of around ten months. At the beginning around 30,000  barrels leaked out a day, after the first repairs it was still around 20,000 barrels a day in July and after extensive sealing of the borehole at the beginning of August still around 10,000 barrels a day. The oil leak was finally stopped after 294 days on March 23, 1980 after two relief wells. The estimates for the total amount of spilled crude oil are 440,000 to 1,400,000 tons.

Oil spill

Extinguishing work after the accident

At the scene of the accident, Norwegian experts skimmed off a small part of the oil, for which barriers were used. The disperser Corexit 9527 was applied by airplanes to oil driven away from the scene of the accident over an area of ​​2800 km² . According to PEMEX, half of the leaked oil was burned, a third evaporated, and the rest was skimmed off or dispersed. Nevertheless, relatively small proportions of the total leaked amount reached the coasts of the Mexican states of Campeche , Tabasco , Veracruz and Tamaulipas , and with the predominantly northward current from August 6, 1979, finally also those of the US state Texas . Extensive preparations had been made against the oil, which had meanwhile been heavily weathered, in the two months' warning period available. The mainland coast and the lagoon behind the offshore chain of islands were secured by oil barriers and siphons in the passages between the islands, and the Cedar Bayou was closed by adding sand. On the islands, however, more than 7,500 cubic meters of oily material had to be removed from the beaches, mainly with shovels and rakes.

consequences

The population of birds and marine animals was severely decimated in places and was only able to recover slowly. Tourism on the Texan coast briefly collapsed by around 60%. Although the state-owned company PEMEX was responsible for the disaster, the Mexican government refused to accept any compensation for costs on the American side.

See also

Web links

Individual evidence

  1. ↑ NOAA IncidentNews: Ixtoc I ( Memento from October 14, 2012 in the Internet Archive )
  2. ↑ National Oceanic and Atmospheric Administration, Office of Response and Restoration: Ixtoc I, Countermeasures / Mitigation ( Memento from September 22, 2008 in the Internet Archive )

Coordinates: 19 ° 24 ′ 50 ″  N , 92 ° 19 ′ 50 ″  W.