The oil well that caused the 2010 Deepwater Horizon explosion was the Macondo well, drilled in the Macondo Prospect in the Gulf of Mexico.
The well was located in Mississippi Canyon Block 252, roughly 40 miles southeast of the Louisiana coast. BP operated the prospect, with Anadarko Petroleum and MOEX Offshore 2007 holding minority interests. Deepwater Horizon began drilling the exploratory well in February 2010 in approximately 5,000 feet of water.
On April 20, 2010, high-pressure methane escaped after failures in the well’s cementing and well-control systems. The gas rushed up the marine riser and ignited on the Deepwater Horizon drilling rig. The resulting explosions killed 11 workers, injured 17 others, and caused the rig to sink two days later.
Macondo is commonly used for both the well and the wider prospect, while Deepwater Horizon refers to the drilling rig. The accident also triggered the largest marine oil spill in U.S. history; the well was finally sealed in September 2010.