MICROFACIES, DEPOSITIONAL ENVIRONMENT, AND DIAGENETIC PROCESSES OF THE MAUDDUD MEMBER, IN THE PERSIAN GULF

Mauddud member with the age of late Albian to Cenomanian is equivalent to the lower Sarvak formation in the southern Persian Gulf and adjacent area. In this work, microfacies, depositional environment, and diagenetic processes affected the Mauddud member in a field in the Persian Gulf are investigated. Based on the studies of available cores and thin sections of 3 wells, five types of microfacies, namely MF1 to MF5, have been identified in the Mauddud member. These microfacies have been deposited in 2 facies belt including a vast lagoon and local bioclastic shoal. Based on the lack of great barrier reefs and calciturbidities and gradual change of microfacies into each other, it is concluded that the Mauddud member was deposited on a shallow marine homoclinal ramp. Several diagenetic processes such as bioturbation, micritization, dissolution, cementation, dolomitizetion, and compaction have influenced this member. Among all, dissolution increased porosity and thereby reservoir quality, while cementation and compaction decreased reservoir characteristics. Finally, it was found out that matrix porosity was the main type of porosity in the studied interval.