Abstract The Jennings oil field was one of the earliest oil fields of the first class on the Gulf Coast. It is on a dome in Tertiary sediments. Although the salt has not been drilled into, limestone which has never been drilled through and which resembles cap rock underlies the main part of the field, and is taken to indicate the presence of a salt dome. There is a surface mound that is probably the remnant of a salt dome mound and a depression that in part is probably a “central depression.” The Jennings field has been one of the most prolific of the Gulf Coast oil fields, and had many long-lived wells with enormous total production.

Abstract The Jennings salt dome is one of the first domes recognized in the Gulf Coast, having been discovered in 1901. However, the salt was not encountered and cap rock wholly penetrated until after 1926, when the structure was definitely proved to be a true salt dome. Drilling exploration for the past nine years has been limited to the flanks of the dome, mainly its southeast flank. The Yount-Lee Oil Company has drilled the west, north, and southeast flanks of the dome. The southeast flank is the only one proved productive, with four wells now producing out of fourteen drilled. Geophysical as well as geological observations have indicated an overhang on the southeast flank. The productive sands on this flank are Middle Oligocene in age and are classified as high-pressure sands.

Abstract The utility of micropalaeontology and biostratigraphy has perhaps been nowhere better demonstrated than in the Gulf Coast of the United States. Gulf Coast micropalaeontology and biostratigraphy evolved through several phases in response to the shift in exploration from onshore to the deep Gulf of Mexico. During this time, micropalaeontology and biostratigraphy morphed into the discipline of chronostratigraphy while playing critical roles in exploration due to the complex geometries produced by the interplay of sea-level change, shifting loci of sedimentation and diapirism. Micropalaeontology, biostratigraphy and their latest incarnation of chronostratigraphy have contributed to the discovery, exploration and development of new fields and trends while saving countless hundreds of millions, if not billions, of dollars in exploration and development costs, as well as significantly adding to reserves by discovering new reservoirs that would otherwise be missed by the drill. Chronostratigraphy will continue to play a critical role in the exploration and development of the latest Gulf of Mexico frontier play: the Lower Tertiary Deepwater Wilcox Trend.