Crude oil inversion study from the Albian-Turonian Sarvak reservoirs in one of the oilfields of SW Iran

Crude oil inversion study using thin layer chromatography (Latroscan TLC-FID), Gas Chromatography (GC), Gas Chromatography-Mass Spectrometer (GC-MS), isotope-ratio mass spectrometry (IR-MS), API gravimetry, elemental analysis, was performed on some crude oils from the Albian-Turonian Sarvak reservoirs in one of the oil-fields of southwest Iran. Aim of this study is to characterize origin, thermal maturity, lithology, and depositional environment conditions of source rock and organic matter.Maturity-related biomarker parameters, aromatic compounds and data from GC indicate that Sarvak oils have been generated from a (high) mature source rock. Other molecular geochemistry data, for example sterane homologs distribution pattern (C27, C28 and C29) and carbon isotope ratio (δ13C) data confirms the Sarvak oils have a marine-carbonate source with mainly planktonic and/or bacterial input (Type II kerogen), deposited under anoxic condition. According to occurrence of sulfur-rich oils from the Sarvak reservoir (4.6 wt.%), it seems these oils were generated from sulfur-rich organic matter (Type IIS kerogen). Oil samples related to Mesozoic carbonates