ABSTRACT

In 1979, shallow Miocene natural gas was discovered in southwestern Baldwin County, Alabama. Only three years later, Miocene gas was discovered in southern Mobile County as well as the southern portions of Mobile Bay. These events have led to a highly successful exploration program for middle and late Miocene natural gas reservoirs throughout southern Alabama and its adjoining State waters. Since these initial discoveries over 200 Miocene test wells have been drilled in this area resulting in the discovery of 42 Miocene natural gas fields. The abundance of subsurface bore holes and accompanying data form an invaluable database for evaluating the local and regional geology and geologic history of the Miocene and in defining the geometry and reservoir characteristics of its producing fields.

To date, over 105 billion cubic feet of natural gas has been produced from the 42 Miocene fields in the study area. This production has been from five formal and informally named sands within the Miocene Pensacola Clay. Miocene traps are principally stratigraphic-structural combination traps involving pinchouts of porous and permeable sands against regional dip or across anticlinal nosing trends.