Ixtoc

  • Type: Rig
  • field
  • Latitude: 19.4441000
  • Longitude: -92.2166000

Profile of the Ixtoc I Oil Spill

Location and Coordinates

The Ixtoc I oil well was located in the Bay of Campeche, Gulf of Mexico, approximately 100 km (62 miles) northwest of Ciudad del Carmen, Campeche, Mexico. The coordinates of the well are 19°24'30"N, 92°19'30"W.

Operator and Drilling Rig

The well was being drilled by the semi-submersible drilling rig Sedco 135, operated by Pemex, Mexico's government-owned oil company.

Date and Duration of the Spill

The blowout occurred on June 3, 1979, and the well continued to spill oil until it was finally capped on March 23, 1980, nearly 10 months later.

Cause of the Spill

The spill was caused by a wellhead blowout. The incident began when the drill bit hit a region of soft strata, leading to the loss of drilling mud circulation and hydrostatic pressure. Drilling mud escaped into fractures in the rock, and attempts to seal these fractures with materials pumped down the drill pipe failed. This resulted in a large quantity of oil and gas flowing out, which eventually led to a fire and the collapse of the drilling rig's riser, damaging the Blowout Preventer (BOP) stack at the seafloor.

Volume and Extent of the Spill

The Ixtoc I oil spill is one of the largest marine oil spills in history. It released an estimated 3 million barrels (126 million gallons or 480,000 cubic meters) of crude oil into the Gulf of Mexico. The spill affected an area of approximately 2,800 square kilometers (1,100 square miles) and impacted about 261 kilometers (162 miles) of shoreline.

Environmental Impact

  • Oil Distribution: The oil spread across a significant area, impacting south Texas beaches, with an estimated 11,000 metric tons (3 million gallons) of oil reaching these shores. The spill also affected the South Texas Outer Continental Shelf (STOCS) and the biologically productive continental shelf in the Gulf of Mexico.
  • Ecological Effects: The spill had profound ecological impacts, including damage to benthic communities, fisheries, and coastal ecosystems. Studies conducted after the spill used advanced analytical techniques to assess the magnitude and extent of the perturbation caused by the oil. High concentrations of total hydrocarbons were found in surficial sediments in coastal and estuarine systems, indicating long-term environmental damage.

Containment and Remediation Efforts

  • Immediate Response: Initial efforts included pumping mud and "junk" (such as metal balls) into the well to reduce the flow rate. Nearly 100,000 metal balls were pumped into the well, which reduced the flow from 30,000 barrels per day to 10,000 barrels per day.
  • Relief Wells: Two relief wells were drilled to lower the pressure of the blowout, but the oil continued to flow for several months after the completion of the first relief well.
  • Surface Containment: Skimmers, boom lines, and chemical dispersants were used to contain the oil at the surface. Experts, including Red Adair, were involved in the containment and capping efforts.
  • Research and Monitoring: Several research cruises, including those by NOAA and Woods Hole Oceanographic Institution, collected extensive data on the spill's impact and the behavior of oil in the Gulf of Mexico. These studies significantly advanced knowledge on oil spill dynamics and environmental impacts.

Cleanup and Aftermath

  • Capping the Well: The well was finally capped on March 23, 1980, after nearly 10 months of continuous oil flow.
  • Oil Fate: Estimates suggest that half of the released oil burned when it reached the surface, a third evaporated, and the rest was either contained, dispersed, or sank to the sea floor. About 6% of the oil was washed ashore in adjacent coastal areas, and 3% reached U.S. beaches.

Long-Term Consequences and Studies

  • Environmental Assessments: A multinstitutional task force, “Programa Coordinado de Estudios Ecológicos en la Sonda de Campeche” (PC-EESC), was established to assess the environmental damages. The United Nations Environment Programme (UNEP) also conducted a detailed assessment of the spill's impacts.
  • Ongoing Research: The spill led to extensive research on oil spill dynamics, environmental impacts, and cleanup strategies. It remains a significant case study for understanding and mitigating the effects of large marine oil spills.

The Ixtoc I oil spill was a catastrophic event that highlighted the need for robust safety measures and effective response strategies in offshore oil drilling operations.

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