Microfacies and Sedimentary Environments Investigation at the Ilam and Sarvak Formations Reservoir in Saadat-abad Oil Field

Ilam and Sarvak formations with middle cretaceous age are (belongs to Bangestan group) one of the very important oil and gas reservoirs in the Zagros basine .Ilam formation with carbonate facies is located between sarvak formation and gurpi formation. Based on importance, Sarvak formation has second place after Asmari reservoir. Four under-ground cross sections are selected from these formations in Saadatabad oil field wells No. (A, B, C, D) for investigating studies of sedimentary environments, sedimentary models and reservoir poroperties due to we did petrography and petrophysical studies on these formations .Based on microfacies studies and the results of orthochems, allochem and terigenous elements two sedimentary environments ((1) Shoal and (2) open marine environment) have been identified for ilam formation, and three sedimentary environments ((1) Lagoon, (2) Shoal, (3) Open marine) have been identified for Sarvak formations. Ilam formation included of two facies in Shoal environment and five facies in Open marine environment. Also, Sarvak formation has 16 facies in Lagoon, Shoal and Open marine environments , which indicates the production of the formations in a carbonat platform (a low slop carbonate ramp). The comparison between their facies and well logs (gamma ray, Sonic, Notron and Density) has shown that the their changing trends are coincident with together.