Quantitative hydrocarbon generation and charge risk assessment in the NW Persian Gulf: A 3D basin modeling approach

Abstract

Abstract Three-dimensional basin and petroleum system modeling was conducted to investigate hydrocarbon generation, migration, and accumulation in the Iranian sector of the NW Persian Gulf. The presented basin model was developed based on seismic and well data covering an area of about 20,000\xa0km2 bounded by the base-Triassic and the present-day sea-floor. Hydrocarbon generation modeling uses newly developed discrete activation energy distributions for Albian source rocks. This study provides a key to the understanding of the Cretaceous-Tertiary petroleum systems and hints to the possible causes of exploration failure at few places. This can reduce future charge-related exploration risk in the region especially for the stratigraphic and combined structural-stratigraphic traps. The modeling results indicate the major role of the Zagros orogeny on controlling burial and thermal evolution as well as hydrocarbon migration and accumulation. The Zagros orogeny and following reactivation of the deep-seated faults resulted in the creation of two depressions in the region hosting the main hydrocarbon generation kitchens for the Cretaceous source rocks. The direction of hydrocarbon migration and accumulation is mainly controlled by the kinematics of the structural highs. During the Late Cretaceous to Miocene, southward deepening of the basin directed most hydrocarbon migration towards the northern part. The latest phase of the tectonic activity during the Miocene and tilting and deepening of the horizons towards the NE resulted in changing the direction of hydrocarbon migration towards the southern part. The results show that the rather young petroleum accumulations related to the Late Miocene to recent Zagros movements can hardly been understood without considering filling of former structures and re-migration due to tectonic restructuring.