Emerging Unconventional Resource Plays in the Onshore Gulf of Mexico: Assessing Agua Nueva and Tuscaloosa Play Potential

Abstract

The Agua Nueva in Mexico and the Tuscaloosa in Louisiana–Mississippi are emerging resource plays deposited during the Cenomanian–Turonian. These high-interest plays are the lateral extensions of the age-equivalent Eagle Ford, a prolific resource play in Texas that has produced more than 4,000 MMBOE. Production sweet-spots within the Eagle Ford are well understood; they are primarily controlled by maturity, mineralogy, net thickness, and reservoir pressure. Are the Agua Nueva and Tuscaloosa plays comparable to the Eagle Ford, and can understanding gained in a data-rich play be applied to characterize emerging plays where date are more limited? In this study, diverse public domain datasets integrated within a sequence stratigraphic framework are used to evaluate the unconventional prospectivity of the Cenomanian–Turonian interval from Mexico to Mississippi. A regional evaluation of the depositional setting and organic-enrichment drivers for these units enables the prediction of source-rock quality, net thickness, and mineralogy. A structural depth model is used to evaluate critical parameters, such as maturity and reservoir pressure. These outputs enable mapping and high-grading of the prospective play areas, and provide the basis for a regional resource in-place assessment. Organic-enrichment within the Eagle Ford play is related to restriction behind a series of drowned paleo-shelf margins that constitute inherited paleobathymetric features, with biological productivity enhanced by adjacent oceanic upwelling. These features extend into Mexico, but a large extent of the Agua Nueva was deposited distal to this paleo-shelf margin where bottom waters were likely to have been more oxygenated. Behind the paleo-shelf margin, organic-enrichment within the Agua Nueva is comparable to the Eagle Ford. However, screening results indicate that the play extent is only 20% of that within the Eagle Ford, and the high-graded areas are limited. To the east, the paleo-shelf margin continues into Louisiana, but clastic influence from the Woodbine and Tuscaloosa deltas overwhelmed the carbonate system. Although the Tuscaloosa play may have unconventional potential within the organic-rich Tuscaloosa Marine Shale, the play is not analogous to the Eagle Ford because the timing and driver of organic-enrichment are different, which affects net thickness. Low maturity, low pressure, and high clay content are all likely to inhibit production relative to the Eagle Ford play.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018