Reservoir quality of lower Teritary sandstone reservoirs along the Texas Gulf Coast is controlled by sandstone depositional environment, mineralogical composition, and consolidation history (compaction, cementation, and leaching). In general, shallow reservoirs have primary porosity that is reduced by compaction andcementation, whereas deeperreservoirs result from late subsurface leaching.
Frio sandstones have the following idealized consolidation history:

Aquifers in the Houston-Galveston area are composed principally of fluvial-deltaic sediments. The Alta Loma Sand is a complexly faulted, high-sand-percent unit that represents a seaward progression of fluvial, delta-plain, and delta-front facies. The Beaumont Formation, overlying the Alta Loma Sand, is a high-mud-percent unit that represents a coastal progression of delta-plain to delta-front facies. Four arbitrarily defined intervals from land surface to 2000 ft indicate superposition of dip-oriented and strike-oriented high-sand-percent trends.

The State of Texas has about 367 miles of open Gulf shoreline, most of it typified by rather broad, sandy beaches and a comparatively mild climate that permits almost year-round use of this recreational resource. All but about 87 miles of the Gulf beach is accessible to the general public.

The Texas Coastal Zone is marked by diversity in geography, resources, climate, and industry. It is richly andowed with extensive petroleum reserves, sulfur and salt, deep-water ports, intracoastal waterways, mild climate, good water supplies, abundant wildlife, commercial fishing resources, unusual recreational potential, and large tracts of uncrowded land in close proximity to major population centers.

Sequential shoreline monitoring, using vintage chans and aerial photographs, documents temporal and spatial variations in historical Gulf shoreline changes. The regional distribution of shoreline erosion and accretion largely reflects changes in littoral drift cells, decreases in sediment supply, and continuing relative sea-level rise including compactional subsidence. A Late Quaternary (circa 3500 BP) shoreline is postulated with promontories at the Holocene Brazos.