Highlights

Abstract

Keywords

۱٫ Introduction

۲٫ Tectono-stratigraphic evolution of the Zagros basin during the Paleozoic

۳٫ Material and methods

۴٫ Results and discussion

۴٫۱٫ Essential elements of the Paleozoic petroleum system

۴٫۱٫۱٫ Source rock

۴٫۱٫۲٫ Carrier/reservoir rock

۴٫۱٫۳٫ Seal rocks

۴٫۲٫ Processes of the Paleozoic petroleum system

۴٫۲٫۱٫ Hydrocarbon generation from the source rock

۴٫۲٫۲٫ Migration of generated hydrocarbon

۴٫۲٫۳٫ Trapping style

۴٫۳٫ Implications for future exploration and production activities within the Paleozoic petroleum system

۵٫ Conclusions

Credit author statement

Declaration of competing interest

Acknowledgments

References

Abstract

The Paleozoic petroleum system of the Fars Platform of Iran is analyzed using 1D petroleum system models of 17 deep wells drilled in the study area. The main aim was to investigate the hitherto undocumented influence of salt tectonics on the essential elements and processes of this petroleum system. For the first time, a better understanding about the geohistory evolution of this prolific petroleum system is provided over the Fars Platform. Modeling results indicate that hydrocarbon generation from the Silurian source rock was associated with salt withdrawal synclines. Salt tectonics further controlled the entrapment styles and the geometric distribution of carrier/reservoir rocks and their overlying evaporitic seals. Our findings provide new insights for identifying the remaining exploration potential in the Paleozoic petroleum system of the Fars Platform and suggest that the role of salt tectonics should be considered in the future basin and petroleum system modeling studies in this area.

۱٫ Introduction

Petroleum system analysis has become a critical part of hydrocarbon exploration portfolio in recent years (Allen and Allen, 2013; Alves et al., 2020; Lawson et al., 2018; Magoon and Dow, 1994). It helps exploration geologists to obtain a holistic understanding about the geohistory evolution of the petroleum systems in space and time and to study the complex interaction of many processes influencing the essential elements and processes of the petroleum systems (e.g., Fraser, 2010; Peters et al., 2017). In this study, a preliminary analysis of the Paleozoic petroleum system is conducted for the first time in the Fars Platform of the Iranian Zagros basin (Fig. 1).

The Fars Platform of the Zagros basin is an extremely prolific hydrocarbon province, with several giant and super-giant gas fields in the Paleozoic series (Bordenave, 2008, 2014; Esrafili-Dizaji and Rahimpour-Bonab, 2019). The Paleozoic petroleum system in the Fars Platform contains significant gas reserves in the Permo-Triassic carbonates (Dalan and Kangan formations) in numerous onshore and offshore fields (Esrafili-Dizaji and Rahimpour-Bonab, 2013, 2019; Ghazban, 2007; Kashfi, 1992) (Fig. 1). Notwithstanding the very old history of oil exploration in this basin (i.e. as early as 1900’s), its various petroleum systems were not systematically studied until recent years. The Paleozoic system of this basin is especially less explored and little is known about its stratigraphy (Ghavidel-syooki, 1997; Ghavidel-syooki, 2003; Insalaco et al., 2006; Spina et al., 2018; Szabo and Kheradpir, 1978) and petroleum geology (Alipour et al., 2021; Bordenave, 2008; Esrafili-Dizaji and Rahimpour-Bonab, 2013, 2019; Motiei, 1993).

The main focus of this paper is to analyze the essential elements (i.e. the source rock, carrier, reservoir, and seal rock) and processes (i.e. hydrocarbon generation, migration, and entrapment) for the Paleozoic petroleum system of the Fars Platform. We highlight that the tectonostratigraphic evolution of this area had a great impact on the spatial and temporal evolution of the Paleozoic petroleum system. Results from this study can provide essential input parameters for basin and petroleum system modeling studies in the future. In addition, a better understanding is obtained about the existing play fair-ways and remaining exploration potential in the Paleozoic petroleum system of the Fars Platform.