Exploring deep Mesozoic reservoirs in the Lower Kura Basin: neotectonic controls and fluid behavior in the Yevlakh-Agjabadi Depression, Azerbaijan

The Central Deep Zone of the Yevlakh-Agjabadi Depression in the Lower Kura Basin (Azerbaijan) represents a promising yet underexplored frontier for reservoir potential within Mesozoic (Cretaceous-Jurassic) sequences. This study integrates regional geophysical data, deep-well logs, and lithostratigraphic analyses to investigate fluid dynamics, neotectonics, and reservoir potential of these deep complexes. Since the mid-20th century, seismic, gravimetric, and magnetometric surveys-complemented by more than 30 deep exploratory wells-have revealed a complex tectonic framework characterized by multi-level dislocations, intense volcanism, and significant stratigraphic variability. Cretaceous-Jurassic successions reach thicknesses of up to 2,000 m and comprise mixed carbonate, terrigenous, volcaniclastic, and effusive lithologies, including basalts, andesites, and porphyrites.
Recent reinterpretation (2019-2020) of 2D/3D seismic profiles acquired by ConocoPhillips (2012) and SOCAR’s POGE (2014-2017) has refined the deep structural architecture, confirming potential structural and stratigraphic traps within buried anticlines and fault-bounded compartments. Stratigraphic analysis indicates that the depositional basin closed during the Paleocene but re-opened and deepened during the Eocene-Maikop, facilitating the accumulation of thick, organic-rich shales that likely serve as both source and seal rocks. The widespread direct contact between Eocene sediments and Cretaceous basement supports this model of renewed subsidence and favorable conditions for hydrocarbon generation and entrapment.
Reservoir quality remains challenging due to low primary porosity (typically <7%) and heterogeneous fracture networks. However, secondary porosity generated by tectonic fracturing, hydrothermal alteration, and weathering of volcanic units enhances storage and flow capacity in localized zones.
Despite extensive exploration, key uncertainties persist regarding trap integrity, migration pathways, and the spatial distribution of effective reservoirs-largely due to structural complexity and limited well control in the central deep zone. This work aims to reduce those uncertainties by synthesizing multidisciplinary datasets to delineate prospective drilling targets. The findings underscore the importance of integrating neotectonic evolution with fluid dynamic modeling to improve exploration success in deeply buried, volcanically influenced Mesozoic systems of the Lower Kura Basin.