Frio Formation of the Texas Gulf Coast Basin : depositional systems, structural framework, and hydrocarbon origin, migration, distribution, and exploration potential

Access full-text files




Galloway, William E.

Journal Title

Journal ISSN

Volume Title


University of Texas at Austin. Bureau of Economic Geology


The Frio Formation is one of the major Tertiary progradational wedges of the Texas Gulf Coast Basin and has yielded nearly 6 billion bbl of oil and 60trillion ft30f gas. The Frio and its updip equivalent, the Catahoula Formation, consist of deposits of two large fluvial and associated deltaic systems centered in the Houston and Rio Grande Embayments. Structures in the Houston Embayment are dominated by syndepositional deformation of underlying Jurassic salt. Mobilization of thick, undercompacted prodelta and slope muds characterized the tectonic evolution of the deltaic sequence in the Rio Grande Embayment. These two major deltaic depocenters are separated by a vertically stacked, strike-parallel barrier and strandplain system.

Underlying, interbedded, and transgressive shelf, prodelta, and continental slope mudstone sequences provide principal source and sealing facies. Sparse organic geochemical data and regional thermal and compaction-history analyses show that large volumes of hydrocarbons have probably been generated within, and effectively expulsed upward and landward from, normally to moderately undercompacted sequences of these rnudstone facies.

All Frio depositional systems contain economically significant, geologically defined hydrocarbon producing plays. Volume, production style, and type of hydrocarbon within each of 10 recognized plays reflect source-rock quality and type, differing compaction and pore-fluid-migration history, and reservoir and trap configurations characteristic of each depositional system. Analysis of volumetric, historical, and geological relationships for production and discovery within each play provides a basis for estimating the undiscovered hydrocarbon resource potential as well as for assigning that potential to specific geographic and stratigraphic subdivisions of the depositional basin.


To obtain a print version of this publication visit: and search for: RI0122. Accompanied by 19 plates.

LCSH Subject Headings