Document Type : Original Research
Department of Geology, Faculty of Science, Islamic Azad University - Shiraz Branch, Shiraz, Iran
The Mishan Formation (Middle Miocene) is the middle part of the Fars Group. To determine the limiting factors of reservoir potential in the Mishan Formation in Fars Province, three geological cross sections in western Fars and a comparative one southwest of Boushehr have been studied. In these sections the Mishan Formation consists of shale, marl and sandstone and limestone facies. Poorly developed primary and secondary porosity features on the one hand, and occurrence of porosity decreasing diagenetic processes such as cementation, compaction, calcite and silica fillings and also bioturbation on the other hand lead to absence of sufficient porosity in these deposits.