The Permo/Triassic of Iran, Mainland and Offshore

By

Ali Golestaneh¹

(1) International Petroleum Consultant, N/A, Iran

 An update is available on the surface and subsurface of the Permo/ Triassic of Southwest Iran, in particular highlighting its stratigraphy, sedimentology, and paleontology.

To gain a more in-depth understanding of the great profusion of the natural gas, some 30% of the total gas reserves of the world, details on a) the surface (high mountains of the Zagros region) and b) subsurface (Southwest Iran to the mainland and offshore area of the Persian Gulf), will be presented.

Sedimentologically, seven regressive sedimentary cycles are distinguished in the Permo/Triassic sequence. Reservoirs are restricted to the grain supported textures with some local variations, which may have caused by anhydritization, dolomitization and varying intensity of anhydrite leaching. Fissures and fractures also play in later upgrading of the reservoir potential. Diagenesis and reservoir distribution seem to be restricted to the Dalan and Kangan Formations, which may contain the main gas reservoirs.

Palentologically, thin section study of the Permo/Triassic sediments in the surface and subsurface provided some sixty different foraminiferal and algal forms to be used for local and regional correlation and supporting evidence for the Permian/Triassic boundary. The Permian section penetrated in the waters of the Persian Gulf area is also discussed.