Garau Formation as an unconventional hydrocarbon resource in southwestern Iran: a geochemical investigation

Abstract Due to the growing need for hydrocarbons and limited conventional resources, paying attention unconventional oil gas resources is essential. The upper Jurassic-Lower Cretaceous in western southwestern Iran contains most crucial source rocks of Zagros sedimentary basin. One richest shaly Garau Formation. Owing geochemical geological characteristics, Formation, with Neocomian Coniacian age periodicity radiolore black limestones pyrite bituminous shales, ammonite, chertite shale, suitable potential sweet spot as shale shale. In this study, a comprehensive regional study was conducted on entire Formation basin using Rock–Eval parameters organic matter maturity data. addition investigating hydrocarbon generation rock, prospect shales investigated. For purpose, 31 fields 5 important sub-basins Zagros, including East Lorestan, West Izeh zone, Dezful Embayment, Abadan plain were showed that total carbon varies between 0.17 24.6, more than 75% had values greater 1. By examining quantity, quality, considering necessary thresholds, it found Lorestan have conditions shales. highest quantity best quality are related Eastern Lorestan. moving west south Basin, decrease, hydrogen index proves results. Vitrinite reflection studies indicated lowest levels belong respectively. Therefore, northeast Basin (Eastern Lorestan) has northwest (Western