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Mapping the Jurassic Norphlet Sandstone along the Northern Margin of the Yucatan Peninsula


The Oxfordian Norphlet Formation is an aeolian sandstone with an aerial extent of several hundred thousand square kilometers, stretching across Louisiana, Mississippi, Alabama and into the deepwater Gulf of Mexico. Beginning with onshore discoveries in Mississippi in the 1960's, the Norphlet and the overlying Smackover Formation's economic importance has driven extensive exploration offshore Mississippi, Alabama, and Florida. The first well targeting the deepwater Norphlet play was drilled in 2003 in the De Soto Canyon protraction, which encountered approximately 30 m of oil column within the aeolian sand. For exploration targeting the Norphlet, primary protractions of interest in the US Gulf of Mexico include De Soto Canyon, Lloyd Ridge, and Mississippi Canyon. Here, the Norphlet section is typically overlain by the Smackover Formation which acts as both seal and hydrocarbon source for Norphlet reservoirs. Using long offset 3D seismic data from Lloyd Ridge we characterize probable Norphlet dune structures, including clear images of the underlying Louann salt. The occurrence of aeolian sands of Oxfordian age on the northern Yucatan shelf has received relatively little attention, despite its likely pre-rift continuity with the Norphlet Formation of the northeastern GOM. Given its onset of deposition near 161 Ma and the initiation of seafloor spreading in the eastern GOM around 158 Ma, it is likely these unnamed sands of the northern Yucatan margin are related to the Norphlet Formation of the northeastern GOM and form a previously unrecognized, prospective fairway. Using a late Jurassic tectonic reconstructions based on gravity and magnetic data, we have positioned the Yucatan block adjacent to the northeastern GOM to illustrate the pre-rift continuity of the two units. We use well data with 20,000 km of 2D data and 12,000 km2 of 3D data from the US and Mexico GOM to map a section that appears to have the upper section extension and lower section folding characteristic of a Norphlet sand deposited on top of a salt layer. The hydrocarbon prospectivity of the underexploited Yucatan Norphlet fairway is evaluated in relation to its productive northeastern GOM counterpart. Quantitative reservoir estimations help to establish a play fairway for exploration targeting the Norphlet Formation.