The urban corridors associated with the Dallas, Austin, and San Antonio metropolitan areas lie on Austin Chalk outcrop. In these areas of rapid urbanization, ground-water information is needed to resolve environmental issues. The Austin Chalk also produces hydrocarbons in the deep subsurface. Fluid migration in both oil-field and ground-water environments is strongly controlled by fractures. In each geologic setting, a conceptual model of fracture intensity is required to model or predict flow. Using geologic and engineering data collected during development of the U.S.

Facies architecture, structure, and diagenesis control reservoir geometry and distribution of remaining oil in shoreface, fluvial, and deltaic reservoirs of Miocene age in the 18-mi2 (46.7-km2) Mioceno Norte Area in northern Lake Maracaibo. This mature field is undergoing depletion and nearing the final stages of primary recovery.