The South Texas report includes 58 counties in Texas Railroad Commission Districts 1, 2, and 4, and the offshore area. District 1 exploration activity decreased 16% from 1977. However, the success rate increased to 30.7% as 54 gas completions and 35 oil completions were reported.

District 2 exploration activity increased a significant 36% with a total of 466 wells drilled. The heaviest sustained activity continues to be in the Frio trend in Jackson, Victoria, Refugio, and Calhoun Counties. The greatest new effort appears in the Miocene trend of Calhoun, Lavaca, and Victoria Counties. Development activity increased from 488 wells in 1977 to 596 wells drilled in 1978.

District 4 exploration activity increased a modest 6.2% from 1977 drilling. There were, however, significant new discoveries in the deep Frio trend of Brooks and Hidalgo Counties and in the lower Wilcox trend in Webb County. The most actively explored trend in District 4 was the Frio, followed by the Vicksburg and Wilcox trends. Increased activity in the coastal Miocene trend promises new potential.

Exploration activity in the South Texas offshore increased from 59 wells in 1977 to 143 wells in 1978. Development drilling showed a 12-fold increase to 147 wells in 1978.