عنوان مقاله [English]
The Middle Jurassic Sargelu Formation consists of gray shales and argillaceous limestones in the southwestern Iran. According to lithology, petrophysical and geochemical characteristics, Sargelu is considered as a probable active source rock in the southwestern Iran. The purpose of this paper is to evaluation of hydrocarbon generation potential of Sargelu Formation and its distribution of quantity, quality and maturity in Lorestan, Abadan plain, Dezful embayment, and northwestern Persian Gulf. The evaluation is based on Rock-Eval and vitrinite reflection results of 365 samples from 16 fields and outcrops. Geochemical parameters indicate very good hydrocarbon generation potential for Sargelu during the geological time in different parts of study area.
Several petroleum systems are active in the southwestern Iran and different formations are considered as first or secondary source rock for them. Sargelu Formation is one of the richest source rocks for Jurassic petroleum system in the southwestern Iran and Arabian adjusting areas. Although several researches have been evaluated petroleum potential of Sargelu in the south-west of Iran, none of them study Sargelu in a regional scale. This work assesses hydrocarbon generation of Sargelu (quantity, quality and maturity) in the regional scale in the southwestern Iran and northwestern Persian Gulf. The study area is approximately 725 km long and 350 km wide.
Methodology and Approaches
This study discusses the petroleum potential of Sargelu Formation in south west of Iran, based on data collected from different studies carried out previously. 365 Rock-Eval and 31 vitrinite reflectance data from 16 fields and outcrops were uploaded and evaluated by p.IGI.3.5.1 software.
Results and Conclusion
Approximately 95% of the samples have a TOC content > 1%, which is consistent with good to very good source rock potential. TOC and HI vary from 0.13 to 26.42 and from 0.9 to 1168, respectively. Samples from eastern Lorestan basin (Gashoon, region 1 to 5) indicate good to very good petroleum potential with kerogen type II, while samples from Dezful embayment and Abadan plain indicate fair to good petroleum potential with kerogen type III and II/III. Moreover, samples selected from western Lorestan basin have kerogen type III/IV. The trend of maturity of Sargelu source rock in the study area is exactly in inverse relation to TOC and HI distribution indicating Sargelu in western Lorestan basin, Dezful embayment and Abadan plain generates high amount of oil and gas during geological time with increasing its maturity.