AAPG Foundation 2019 Grants-in-Aid Projects

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Modeling Divergent Structural Histories and their Effect on Agrio Source Rock Thermal Maturity in an Atypical Petroleum System: Neuquén Basin, Argentina


The Cretaceous Agrio Formation (Fm) found in the Neuquén Basin of Argentina, a carbonate mudstone-rich source rock, is now an emerging international shale oil play. The Agrio Fm and existing well infrastructure spans both the Andean Fold-Thrust Belt to the west as well as the adjacent foreland basin to the east. It is important to investigate the impact of divergent structural histories on the thermal maturity of the Agrio Fm hydrocarbons due to the potential of its development as an unconventional play. Variable locations along a fold-thrust belt and foreland basin system experience different tectonic events and different burial histories due to variable rates of uplift, deposition, and subsidence. Thus, the thermal maturity of source rocks subject to these variable structural histories of this complex tectonic setting can change drastically. A comparative study of the effect structural history plays on the thermal maturity of Agrio source rock will help elucidate this often multifaceted relationship. The goal of this research is to compare the development of Agrio source rock intervals in the Chos Malal and Agrio Fold-Thrust Belts in the west to their eastward expression within the Neuquén Basin foreland depocenter. I will create and analyze two, one-dimensional (1D) basin models, one from within the fold-thrust belt and one from within the foreland basin, and compare estimated hydrocarbons in-place in the Agrio Fm. I will utilize PetroMod 2018.2 software package in order to build basin models based on available literature, well logs, outcrop data from the literature and also from Moore et al. (revised), and programmed pyrolysis data from outcrop and cuttings. I hypothesize that Agrio source intervals within the fold-thrust belt are immature to early mature and the intervals within the foreland basin are mature to overmature, but decrease in maturity towards the eastward boundary of the basin. The basin has experienced deeper burial in the proximal-mid foreland of the Andean Fold-Thrust Belt, but less so in the distal portion of the foreland basin. Hence, the Agrio Fm may only be prospective as a shale oil play in the less structurally-complex, foreland basin region. This research will delineate prospective regions for unconventional development inArgentina as related to divergent structural histories (i.e., a fold-thrust belt and a foreland basin).