Integrated source rock evaluation along the maturation gradient. Application to the Vaca Muerta Formation, Neuquén Basin of Argentina

Abstract

The Vaca Muerta Formation (Tithonian-early Valanginian) is the main source rock in the Neuquén Basin and the most important unconventional shale resource in South America. In the present study, organic geochemistry, electron microscopy and basin and petroleum system modelling (BPSM) were combined to evaluate source rock properties and related processes along a transect from the early oil (east) to the dry gas (west) window. The unit is characterized by high present-day (1%-8% average) and original (2%-16% average) total organic carbon contents, which increase to-

DEVELOPMENT OF FIBROUS CALCITE VEINS RELATED TO HYDROCARBON GENERATION AND OVERPRESSURING IN ORGANIC‐RICH SHALE SOURCE ROCKS: THE VACA MUERTA FORMATION, NEUQUÉN BASIN, ARGENTINA

“…3), was included in the present study of the thickness and structural configuration of the Vaca Muerta Formation. At the far east of the profile towards the eastern margin of the Neuquén Basin, well E in the NE Platform is located in a relatively undeformed foreland area (Brisson et al, 2020;Spacapan et al, 2021) (Fig. 3).…”

“…The structural evolution of the model was based on previous studies which determined an initial phase of Andean compression in the Late Cretaceous (Tunik et al, 2010;Rojas Vera et al, 2015), with subsequent reactivation in the Oligocene -Miocene and middle Miocene based on apatite fission track data (Rocha et al, 2018). Spacapan et al (2021) described the boundary conditions used in the 2D model, including present-day and palaeo basal heat flows, and surface or sediment-water interface temperatures that were corrected for present-day and palaeo water depths.…”

“…1) and later cross-checked with Hornercorrected bottom-hole temperatures (Deming, 1989). Furthermore, lateral and vertical variations in the organic matter content in the Vaca Muerta Formation was calibrated with geochemical data from wells A, B, C, D and E (Spacapan et al, 2021).…”

“…Rodrigues et al, 2009;Cobbold et al, 2013;Zanella et al, 2015;Ukar et al, 2017aUkar et al, , 2017bUkar et al, , 2020de Barrio et al, 2018;Palacio et al, 2018;Weger et al, 2019;Ravier et al, 2020;Cruset et al, 2021;Larmier et al, 2021), the main source rock and unconventional reservoir in the Neuquén Basin of Argentina (Fig. 1) (Urien and Zambrano, 1994;Cruz et al, 1996;Brisson et al, 2020;Spacapan et al, 2021). Rodrigues et al (2009) proposed that BVPs in the Vaca Muerta Formation consist of two generations of calcite fibres on either side of a median line (or suture): a first generation of calcite in the inner zones of veins which consists of fibres oriented perpendicular to the vein walls; and a more external, second cement generation in which calcite fibres are oblique to the vein walls indicating growth during shearing and layer-parallel shortening.…”

“…The thermal and pressure evolution of the Vaca Muerta Formation was analysed by Spacapan et al (2021) from a 2D model which extended for some 150 km from the Agrio fold-and-thrust belt in the west via the Chihuidos High (CH, Fig. 1) to the NE Platform in the eastern foreland of the basin (Fig.…”