Evaluation of organic geochemical parameters in probable source rock of Zagros sedimentary basin (case study of Pabde h F ormation, Kabirkoh anticline, Ilam province)

In this research, Pabde Formation (Paleocene-Oligocene) was evaluated as one of the hydrocarbon producing formations in the Zagros sedimentary basin from the point of view of organic geochemistry and hydrocarbon generation potential. In this regard, a 180-meter-thick stratigraphic section was selected on the northern side of the Kabirkoh anticline, Dere Shahr city, and 20 healthy and non-weathered rock samples were taken from this section for Rock-Eval 6 analysis. Lithology of Pabdeh formation in the interval study section6 was taken for Rock-Eval analysis. The lithology of Pabdeh Formation in the section under study is an interval of shale and marl, where the shale facies is dominant. Plotting S 2 values ​​against Toc indicates a medium to relatively good source rock for Pabdeh Formation, whose kerogen was detected as a combination of type II and type III, but type II kerogen is more abundant, which can be due to the dominance of marine facies. be the constituent of this formationThe plot of Tmax values ​​against HI showed that 25% of the samples are in the immature range and 75% of them are in the beginning to the middle of the oil generation window, which is confirmed by Tmax between 435 and 460 degrees Celsius. The diagram of HI versus Toc indicates the formation of various organic facies in Pabde formation, these facies include: organic facies C (30 percent), BC (50 percent) and to a lesser extent B (15 percent) and AB (5 percent). This facies diversity can be due to the diversity of organic materials with marine and continental origin and sedimentation in relatively regenerating environments such as the Pro-Delta, the outer shelf, and the upper parts of the continental shelf.