The role of diagenetic processes associated with discontinuity in the development on Sarvak formation reservoir quality (Kupal oilfield)

The Sarvak Formation deposited in the North to Northeastern margin of the Arabian Platform during the Mid-Cretaceous (Albian-Turonain), and is extensively encountered in the Folded Zagros of southwestern Iran. It is the most important reservoir unit after Asmari Formation in Iran. Diagenesis studies using petrographic analysis on thin sections from three development wells indicate an intricate diagenetic history for Sarvak reservoir in Kupal oil field. Meteoric diagenetic processes (including extensive dissolution or karstification, meteoric cementation and dissolution-collapse brecciation) along with burial diagenetic features (including styloliterelated dolomites and burial cements) are introduced as the main diagenetic overprints that controlled the reservoir quality of Sarvak Formation. These are resulted in recognition of a major role for diagenetic overprints on shaping the final reservoir quality of Sarvak Formation. Extensive meteoric dissolutions below the disconformities together with styloliterelated dolomitized bodies provided the best reservoir horizons. Aversely, meteoric and burial cementations together with collapsed breccias are introduced as the main factors defeating reservoir quality