Introduction
The purpose of the U.S. Geological Survey's (USGS) National Oil and Gas
Assessment is to develop geologically based hypotheses regarding the potential
for additions to oil and gas reserves in priority areas of the United States.
The USGS recently completed an assessment of undiscovered oil and gas potential
of the Cambrian-Ordovician carbonate rocks, the Chattanooga and Floyd Shales,
and the Pottsville Formation coals in the Black Warrior Basin Province in
northeastern Mississippi and northwestern Alabama in the Gulf Coast Region.
The Cambrian-Ordovician carbonate rocks, the Chattanooga and Floyd Shales,
and the Pottsville Formation coals are important because of their potential
for natural gas resources.
This assessment is based on geologic principles and uses the total petroleum
system concept. The geologic elements of a total petroleum system include
hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). The USGS used this geologic framework to define two total petroleum systems and three assessment units. All three assessment units were quantitatively assessed for undiscovered oil and gas resources.
