Mobile Bay, Alabama, Exploration Play

R. E. Roadifer

The idea for an exploration play in Mobile Bay was in the minds of Mobil explorationists in Shreveport, Louisiana, in the late 1950s.

As first defined, the objective was a structural trap in Cretaceous rocks. During the processes of improving seismic data and additional study before drilling, the objective was extended to the Jurassic Smackover and finally to the Norphlet below 20,000 ft.

The 150 million year old sea shore sand dunes, now the Norphlet, with subjacent and superjacent evaporites provide an excellent reservoir, seal, and trap. Generation, entrapment, and preservation of the hydrocarbon accumulation in the Jurassic sandstone reservoir at depths below 20,000 ft are remarkable spectacles of nature.

The leases at Mary Ann field (astride the shipping channel between Fort Gaines and Fort Morgan at the mouth of Mobile Bay) were not acquired until 1969. Protracted permit problems, unexpected expense, drilling problems, wildly fluctuating markets, and uncertain supply and demand had slowed the project. The wildcat well was spudded in November 1978, and suspended (as a gas discovery) in December 1979, at total depth of 21,113 ft.

After more than two decades, the Mobile Bay play is finally approaching production status. Onshore plant facilities, pipeline, and production platforms are contracted for and are nearly a reality. Those of us among the optimists in this industry still look forward to profits from this spectacular venture.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.