About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

South Texas Geological Society Special Publications


Contributions to the Geology of South Texas, 1986
Pages 24-52

Major Oil Plays of South and South-Central Texas

Noel Tyler, Thomas Ewing


South and south-central Texas have experienced a long history of oil exploration and production. During the past 80 years, more than 6 billion barrels of oil have been produced from this region, mostly from seven major oil plays. Reservoir rocks in these plays range in age from Middle Cretaceous (Comanchean Edwards Group) through Oligocene (Frio Formation). The most prolific pools in terms of both cumulative production and recovery efficiency are the younger sandstone reservoirs. Major reservoirs (those with cumulative productions of more than 10 million barrels) in two Frio plays in the Gulf Coast Basin have produced 2.6 billion barrels of oil at an average recovery efficiency of 50 percent. By contrast, major Cretaceous-age reservoirs, excluding the Austin Chalk, have produced a little more than one-half billion barrels at a recovery efficiency of less than 30 percent.

This mature oil province is facing an overall decline in production. Between 1978 and 1985, annual production dropped by 23 million barrels. Oil field re-exploration for non-residual oil trapped by macroheterogeneities in reservoirs offers an alternative method for slowing and perhaps stabilizing production decline. It is estimated that 1.4 billion barrels of moveable oil will remain trapped in major South and south-central Texas reservoirs at abandonment. This target oil is a critical complement to wildcatting in new plays for future exploration strategies in this major oil province of the United States.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24