The Black Warrior basin of northeast Mississippi and northwest Alabama is a triangular area of 35,000 sq mi of Paleozoic strata bounded on the north by the Nashville and Ozark domes, on the southeast by the folded Appalachians, and the southwest by the buried Ouachita mountains. The western two-thirds of the basin is buried beneath Mesozoic and Tertiary strata of the Gulf Coastal Plain and Mississippi embayment.

The first gas production in the basin was established in 1909. Since that time exploration has been sporadic, but in the early 1950's seven Upper Mississippian gas fields and a one-well Ordovician oil field were discovered in the exploration program which followed the development of the Muldon gas field.

During most of Paleozoic time, the basin was part of the stable continental interior and received more than 17,000 ft of sediment typical of that deposited in the shallow inland seas of the era. The center of the basin shifted in each Paleozoic period. In Early Pennsylvanian time, there was a great downwarping of the basin accompanied by an uplift of orogenic belts on the southeast and probably on the southwest; more than 10,000 ft of Pottsville sediment was deposited in the Black Warrior trough. After Pennsylvanian time, the basin was uplifted and received no Permian sediment. In early Mesozoic time, the province was downwarped on the southwest and was covered with the Mesozoic and Tertiary sediment of the Mississippi embayment.

The Paleozoic strata of the basin are complexly faulted, and most of the gas fields are on faulted structural features which were located by geophysical methods. All of the gas production is from Upper Mississippian Chester sandstone beds which have a marked lack of lateral persistence and extreme lateral and vertical variations in porosity and permeability.

The eight-well Muldon field is the largest gas field in the basin. It is on a horst-like fault block, and production is from the Sanders sandstone, of middle Chester age, at a depth of 5,500 ft. Total recoverable reserve of the Muldon field is estimated to be 70 billion cu ft of gas.

Most of the Paleozoic rocks of the basin have abundant oil and gas shows where there is porosity. There are several unconformities in the basin which offer the possibility of large-scale stratigraphic traps, and there are many undrilled structural anomalies. It seems probable that much more oil and gas will be found in the basin in the future.