Organic-rich Stratigraphic Units in the Vaca Muerta Formation, and Their Distribution and Characterization in the Neuquén Basin (Argentina)

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

“…The increase in TOC values from east to west is associated with thickening of the VMFm between ca. 400 and 800 m in the same trend (Dominguez et al, 2016), which means a higher volume of generated hydrocarbons for the same gradient of TR. Notably, Well B shows the highest present-day (mean 8%) and original TOC (mean 18% for the lower VM) contents, which suggests that local effects could have influenced these positive anomalies.…”

“…(2016), organic‐rich intervals in the VMFm correspond to bottomset–distal foreset segments of prograding clinoforms, conditioned by stratigraphic and in some cases tectonic (differential subsidence and palaeo‐arch uplift) controls. The lower VM exhibits mostly stratigraphic controls (Dominguez et al., 2016), and therefore, a position close to the distal foreset is envisaged where optimal conditions for the production and preservation of OM occurred (Passey et al., 2010).…”

“…Notably, Well B shows the highest present-day (mean 8%) and original TOC (mean 18% for the lower VM) contents, which suggests that local effects could have influenced these positive anomalies. As analysed by Dominguez et al (2016), organic-rich intervals in the VMFm correspond to bottomset-distal foreset segments of prograding clinoforms, conditioned by stratigraphic and in some cases tectonic (differential subsidence and palaeo-arch uplift) controls. The lower VM exhibits mostly stratigraphic controls (Dominguez et al, 2016), and therefore, a position close to the distal foreset is envisaged where optimal conditions for the production and preservation of OM occurred (Passey et al, 2010).…”

“…Desjardins et al., 2016; Dominguez & Di Benedetto, 2019; Legarreta & Uliana, 1991; Mitchum & Uliana, 1985; Sagasti et al., 2014). Basin‐scale stratigraphic architecture shows that the unit comprises three to five progradational sequences with organic‐rich transgressive intervals composed of siliciclastic and carbonate‐rich shales that grade upward into highstands dominated by organic‐lean marls (Capelli et al., 2021; Dominguez et al., 2016; Kietzmann et al., 2016; Legarreta & Villar, 2015).…”

“…The hydrocarbon yield expressed as original hydrogen index (HI 0 ) averages 680 mg HC /g TOC based on the analysis of immature samples (Brisson et al, 2020;Veiga et al, 2020). This is representative of the organic-rich intervals (30-450 m thick) considered to be the unconventional targets of the unit (Dominguez et al, 2016). Different patterns of organic richness, hydrocarbon source quality, distribution of free hydrocarbons and thermal maturity allowed Brisson et al (2020) to distinguish six reference areas for the VMFm (Figure 1).…”