The deep lower Tuscaloosa gas trend, now in a mature stage of exploration, was discovered in 1975. Production is from lower Tuscaloosa sandstones of Late Cretaceous age. During the past decade, the petroleum industry has drilled approximately 217 new-field wildcats and 232 development wells in the trend. This exploration effort has discovered 24 fields. Most of these fields produce from depths between 15,000 and 20,000 ft. In February 1984, the average daily production was 426.6 mmcf of gas and 18,350 bbl of liquid hydrocarbons from approximately 115 wells. Five fields, False River, Irene, Judge Digby, Moore-Sams, and Port Hudson, all discovered prior to 1980 and concentrated northwest of Baton Rouge, Louisiana, have produced about 72% of the cumulative gas and 80% of the cumulative liquids.

Reservoirs in deep lower Tuscaloosa occur in a terrigenous clastic sequence, which thickens rapidly downdip from a carbonate shelf of Early Cretaceous age. Occurrences of commercial hydrocarbons in the trend are primarily dependent on depositional environment, syndepositional tectonics, source rock, original sand mineralogy, and burial diagenesis. Salt diapirism is locally important.

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