Overpressure at the Macondo Well and its impact on the Deepwater Horizon blowout.

At the Macondo well, the overpressure (fluid pressure greater than hydrostatic) in the main reservoir is nearly identical to that within a stratigraphically equivalent sandstone at the Galapagos development 21 miles (34 km) to the south; we interpret that the reservoirs share a permeable, laterally extensive, and hydraulically connected aquifer. At Macondo, pore pressure approximately parallels the overburden stress to a depth of 17,640 ft (5,377 m) subsea and thereafter decreases abruptly by 1,200 psi (8.3 MPa) over 370 ft (113 m) as the main sandstone reservoir is approached.