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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 63 (1979)

Issue: 9. (September)

First Page: 1534

Last Page: 1537

Title: Super Overpressured Gas: GEOLOGIC NOTES

Author(s): James M. Forgotson, Sr. (2)


A blowout after acidization of perforations at 10,800 ft (3,291 m) in limestone of the Cotton Valley Group (Upper Jurassic) in a field-extension well in Upshur County, in east Texas, gauged pressure in excess of 12,000 psi before equipment failure. The pressure dissipated rapidly and a 200-ft (60 m) offset well was normal for the field.

Cause of the unique high-pressure zone is unknown. Possibly the high pressure is relict from a time of deeper burial when such pressures were field-wide before uplift and migration. A local chamber or vault, sealed off, for example, by calcium carbonate, may have retained earlier pressures until its walls were dissolved by the acid treatment.

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