Perdido Foldbelt: a New Deep-Water Frontier in Western Gulf of Mexico

Jon Frederic Blickwede, T. A. Queffelec

The Perdido foldbelt is the central part of a major Cenozoic compressional fold system (Gulf of Mexico fold system) in the deep Gulf of Mexico. The southwest and northeast parts of the Gulf of Mexico fold system are the Mexican ridges and Mississippi fan foldbelt, which differ from the Perdido foldbelt in age of deformation and details of structural style.

The Perdido foldbelt formed during the Oligocene(?) by gravity sliding on a salt detachment. The foldbelt consists of a series of southwest-northeast-trending, parallel, concentric, box-style folds whose flanks are cut by reverse faults. Structures are asymmetric and verge both landward and basinward, typical of compressional foldbelts formed above a weak basal detachment.

Individual anticlines are large by Gulf Coast standards, having as much as 120,000 ac under closure and 6,000 ft of relief.

Up to 25,000 ft of Jurassic-Oligocene(?) sedimentary rocks are involved in the structures. Projected reservoir facies are: (1) Lower Cretaceous fore-reef carbonate debris analogous to the major productive section in Poza Rica field, Mexico, (2) Upper Cretaceous chalks, and (3) Tertiary turbidite sands equivalent to Wilcox-Frio delta systems in the Rio Grande embayment. Lopatin thermal history models suggest that the Mesozoic section is at peak oil generation at present. Adequate hydrocarbon seal lithologies are likely to be present throughout the section, because of the expected abundance of deep-marine shale and micrite.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.