Diagenetic factors controlling reservoir quality in the Faraghan Formation (Lower Permian), Darang Field, Southern Iran

The role of diagenesis in affecting (reduction or enhancement) reservoir quality in the Faraghan Formation in Darang #1 well was investigated. The Faraghan Formation is mainly composed of sandstone facies along with minor mudstone and siltstone and grades upward into mixed carbonate -siliciclastic facies and then to Dalan Formation carbonates. Depositional environment of this formation comprises various sub-environments of a delta setting in the lower part of the formation which grades upward into a shallow marine clastic environment in the upper part. The processes enhancing reservoir quality include dissolution of carbonate grains and cements and alteration of feldspar grains. Burial history diagram shows that after deposition during Lower Permain, the formation underwent a rapid burial up to 1000 meters below sea level in Upper Permian. Then a slight uplift (about 100 meters) and gradual burial followed up to Mid-Jurassic. Afterwards the formation experienced a series of rapid and moderate uplift from ...