Depositional environment, and sequence stratigraphy of the Lower Cretaceous Fahliyan Formation (Zagros Basin, SW Iran)

The Lower Creataceous Fahliyan Formation of the Khami Group in the studied oil fields (Darquain and Arvand) hosts important hydrocarbon reservoirs in SW Iran. In the studied wells (well No. 33 in Darquain oil field and well No. 2 in Arvand oil field), the thickness of this formation is 280 and 110 meters, respectively. In both oil fields, the lower boundary with the Hith Formation is unconformable, while the upper boundary with the Gadvan Formation is conformable. The core and cutting analysis were used to identify four facies associations with 12 microfacies which can be grouped into four depositional environments: tidal flat, restricted lagoon, shoal and shallow open marine, deposited on a homoclinal ramp. Based on microfacies analysis and sequence stratigraphic concepts, 3 (in Arvand oil field) and 4 (in Darquain oil field) 3rd‑order sequences were identified. Palaeogeographic data show that the deposition of the Fahliyan Formation occurred at low latitudes near the equator.