Modeling Petroleum Expulsion and Retention From the Source Rock within the Vaca Muerta Formation, Neuquen Basin, Argentina
The objective of this study is to achieve a fundamental understanding of petroleum expulsion and retention from a source rock through modeling and numerical simulation using multidisciplinary datasets of the Vaca Muerta Formation in the center of Neuquén Basin of Argentina. The Neuquén Basin generally evolved through three stages of tectonic evolution: extension in Late Triassic to Early Jurassic, thermal subsidence in Early Jurassic to Early Cretaceous, and compression since Late Cretaceous to present day. Tectonic evolution controls deposition and thermal maturation of the source rock. The Vaca Muerta Formation was deposited during the thermal subsidence stage in a mixed carbonate‐siliciclastic ramp setting. This unit contains two distinct source rock layers: the Late Jurassic (Tithonian) lower Vaca Muerta source rock and the Early Cretaceous (Berriasian) upper Vaca Muerta source rock. The lower Vaca Muerta source rock is thinner (~200m) with mainly massive siliceous mudstone facies, richer organic carbon content (original TOC 3‐10%), and more continuous distribution through slow deposition in basinal to slope environments during transgression. While the upper Vaca Muerta source rock is thicker (~1000m), with less organic carbon content (original TOC 1‐6.5%) and less continuity through faster deposition in basinal to inner ramp marine environment during highstand progradation. The Vaca Muerta source rock is type I and type II kerogen with thermal maturity that varies from 0.5 to 2%RoE vertically and laterally in the study area. The heterogeneity of source rock properties most likely leads to different thresholds for petroleum generation and expulsion with various volumes of petroleum retained. The mechanisms and histories undoubtedly control the variations of petroleum composition and distribution. This poster explores the different methods to investigate expulsion of and the retention of petroleum from the source rock.
AAPG Datapages/Search and Discovery Article #90349 © 2019 AAPG Hedberg Conference, The Evolution of Petroleum Systems Analysis: Changing of the Guard from Late Mature Experts to Peak Generating Staff, Houston, Texas, March 4-6, 2019