Hydrocarbon Production and Potential of Distal Frio Formation, Texas Gulf Coast and Offshore

H. Scott Hamlin

Texas state and federal outer continental shelf waters are the last exploration frontier in the prolific Oligocene Frio Formation. Along the Texas Gulf shoreline and offshore, the distal Frio has already yielded 681 million bbl of oil and 7 tcf of gas from 153 fields. To evaluate potential for further exploration and development of the distal Frio, petroleum production data, regional reservoir-quality, temperature and pressure conditions, and characterization of typical fields were integrated with W. E. Galloway's description of stratigraphy, depositional systems, and structural framework.

Offshore Frio production is concentrated in the Mustang Island and Galveston areas, where reservoir-quality sandstones extend locally as far as 25 mi from the shore. Parts of the North Padre Island, Matagorda Island, and Brazos areas also contain potential Frio reservoirs. Significant new discoveries will be deep (8,000 to > 16,000 ft), high-pressure, gas-prone reservoirs in thin distal deltaic, strike-reworked delta-margin, and distal shoreface to shelf sandstones that could yield 1-100 bcf of gas annually for as long as 10 years.

Potential exists for increasing recovery efficiency from nearly depleted onshore fields. Studies focusing on geologic and fluid-flow heterogeneities to delineate undrained compartments in older reservoirs would be useful in formulating production and development strategies to increase the ultimate hydrocarbon resource base of the distal Frio Formation.

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