Abstract: Subsurface Geology of Corpus Christi Bay, Nueces County, Texas

James W. Collins

Prolific production in Corpus Christi Bay has occurred mainly in the regressive Frio Barrier Bar System and the associated shore face-shelf environment. All production in Corpus Christi Bay area is below the Anahuac transgressive wedge with the greatest accumulation in the 1st Marg. sand, which has produced a minimum of 680 BCF of gas in the Red Fish Bay-Mustang Island Common 10 reservoir, the largest single reservoir in South Texas. The 1st Marg. sands have produced in excess of 990 BCFG from four fields in Corpus Christi Bay.

Shallow hydrocarbons in Corpus Christi Bay are associated with the South Texas Frio Barrier Bar System and are structurally trapped on large fault bound anticlines or up-to-the-coast relief faults.

Deeper production from the Frio Sands is mainly on the Barrier Bar shoreface and associated with fault bounded anticlinal closures. Structural complexity increases with depth especially along the large strike aligned growth faults, some up to 4000 ft displacement, and the associated rollover anticlines, subsidiary faults, and shale plugs. These deeper reservoirs are usually pressure-depletion drives.

The oil industry can point with pride to the co-existence with the fragile bay environment while extracting huge reserves. Most of the wells are on State of Texas marine leases and are controlled by State rules and City of Corpus Christi Bay drilling ordinances.

AAPG Search and Discovery Article #90950©1996 AAPG GCAGS 46th Annual Meeting, San Antonio, Texas