Secondary leached porosity is common to dominant in near surface to deep subsurface lower Tertiary sandstone reservoirs along the Texas Gulf Coast. This secondary porosity is in the form of leached feldspar grains, volcanic rock fragments, carbonate cements, and carbonate-replaced grains.

The Texas Coastal Zone is marked by diversity in geography, resources, climate, and industry.

The State-owned submerged lands of Texas encompass nearly 6,000 square miles (15,540 km²) and extend from Mexico to Louisiana. The area includes the bays, estuaries, and lagoons, as well as the inner continental shelf 10.3 miles (16.6 km) seaward of the Gulf shoreline (fig. 1).

Sequential shoreline monitoring, using vintage chans and aerial photographs, documents temporal and spatial variations in historical Gulf shoreline changes.

Geologic map that depicts surface geology of Starr, Hidalgo, Willacy, and Cameron Counties and parts of Zapata, Jim Hogg, Brooks, and Kenedy Counties.

Disposal and temporary surface storage of spent geothermal fluids and surface subsidence and faulting are the major environmental problems that could arise from geopressured geothermal water production.

Historical monitoring along Brazos and south Padre Islands records the nature and magnitude of changes in position of the shoreline and vegetation line and provides insight into the factors affecting those changes.

The Texas Coastal Zone is marked by diversity in geography, resources, climate, and industry.

The stratigraphic record yields evidence that each episode of clastic silicate deposition has been of limited duration and that each has been preceded and followed by a significant hiatus.

A preliminary study of the Frio sand distribution and formation temperatures and pressures was undertaken in order to define prospective areas in which a more detailed reservoir analysis is necessary prior to the selection of a site for a geothermal well.