Authors
1
PhD student, , Science and Research Branch, Islamic Azad University, Tehran, Iran
2
School of Geology, University of Tehran, Enghelab Ave.
3
Department of Earth Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
10.22055/aag.2022.41688.2314
Abstract
The Fahliyan Formation in the Doroud-Kharg oil field is located northwest of the Persian Gulf, with an approximate thickness of 350 meters. This formation is deposited in a ramp-type carbonate platform and has been affected by various diagenesis processes. Sedimentological studies led to the recognition twelve microfacies deposited in open marine, shoal, lagoon, and tidal flat facies belts within a homoclinal ramp. Petrographic studies of the Fahliyan Formation, including diagenetic evidence, indicate that the moldic, interparticle, vuggy, intercrystalline, fractures, growth framework, intraparticle, and fenestral porosities are common porosity types, respectively. Still, interparticle, vuggy, microporosity, and fracture porosity show higher impact the reservoir quality. Here, the reservoir quality has been evaluated by integrating petrographic and petrophysical data, including pore systems examination using capillary pressure curves and considering diagenetic impacts on the primary sediment textures and porosity. Finally, the reservoir quality of the Fahliyan Formation was investigated in the framework of third-order sedimentary sequences corresponding to Manifa (sequence I), Middle Yammama (sequence II), and Upper Yammama (sequence III) members. Accordingly, vuggy and intercrystalline porosity are dominant in sequence I, while interparticle and fracture porosity are the main types in sequence II and III, respectively. Finally, the effect of the various porosity types on the mercury injection curves is investigated, and their impact on the reservoir quality is discussed.
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