Abstract:

The Zagros Basin is the richest petroliferous foreland basin in the world. Based on the newest geological database, with an approach of integrated geological investigation and petroleum system analysis, this paper focuses on the oil and gas distribution patterns and the main controlling factors in the Zagros Basin and discusses the resource exploration potential in the future. Six petroleum systems are recognized, and the Cretaceous/Paleogene composite petroleum system, Jurassic petroleum system and the Silurian Gakhum petroleum system are of great significance. Regionally, the discovered oil and gas reserves are largely confined to the Dezful Embayment, Kirkuk Embayment and Khuzestan Uplift. Stratigraphically, they are mostly reservoired in the Paleogene, Neogene and Cretaceous. The distribution is characterized by patterns of oil in embayments and gas in uplifts. The controlling factors of the hydrocarbons in the Zagros Basin include the excellent regional cap rocks, the stratigraphic distribution of the effective source rocks and the Cenozoic tectonic movement. The results of petroleum resources assessment show that undiscovered oil, gas and condensate resources amount to 44.6×10⁸ t, 9.3×10¹² m³ and 10.4×10⁸ t respectively in the Zagros Basin. Zagros Basin. This study proposes 3 favorable exploration plays: Permian/Triassic Deh Ram play of the Silurian Gakhum petroleum system, Asmari play of the Cretaceous/Paleogene composite petroleum system and Northwest Jurassic play of Jurassic petroleum system.

Key words: Zagros Basin, oil and gas distribution, controlling factor, petroleum system, resource assessment