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

The Vaca Muerta Formation (Tithonian–early Valanginian) is the main source rock in Neuquén Basin and most important unconventional shale resource South America. In present study, organic geochemistry, electron microscopy basin petroleum system modelling (BPSM) were combined to evaluate properties related processes along a transect from early oil (east) dry gas (west) window. unit characterized by high present-day (1%–8% average) original (2%–16% total carbon contents, which increase towards base of basinal settings. Scanning shows that pores derived transformation type II kerogen. Isolated bubble are typical window, whereas densely distributed spongy occur stage, indicating maturity gradient exerts strong control on porosity. Organic pressure porosity data incorporated into 2D model includes sequential restoration tectonic events calculation compaction trends, kerogen transformation, hydrocarbon generation estimation pore through geologic time. W–E regional extends Agrio Fold Thrust Belts border allows us relationship between thermal timing highly deformed undeformed regions. Modelling results show clear decrease matter (OM) eastern margin. Maximum occurred inner sectors belt, at ca. 120 Ma; long before first Andean compression phase, started during Late Cretaceous (ca. 70 Ma). Miocene (15–7 Ma) promoted uplift outer belt associated with reduction stress cracking, as well massive loss retained fluids pressure. OM impacted (a) magnitude effective development, (b) distribution within controlled disequilibrium. BPSM progressive top west region content increasing same trend. Overpressure intervals contents prone develop pores. latter represent favourable sites for storage hydrocarbons Formation.