Sedimentary environment of the Upper Dalan Member in the Qatar- Fars Arc and its eastern margins: South Pars and Salman fields

Permian-Triassic (P-T) hydrocarbon reservoir of the Upper Dalan and Kangan formations (equivalents of the Khuff Formation) are the main hosts of natural gas in the Persian Gulf. The purpose of this study is to investigate and compare of facies changes of Upper Dalan in the South Pars and Salman fields. To better constrain the spatial and stratigraphic distribution of the depositional facies two wells are selected. Facies analysis in the studied wells indicates that these sediments consist of limestone, dolomite and evaporite that were deposited in the inner to beginning of the middle parts of homoclinal carbonate ramp. Petrographic study led to identification fifteen facies and four distinct setting: 1-supratidal (sabkha), 2-lagoon, 3-shoal barrier and 4-open marine. This study showed that facies in Salman field were deposited in a shallower setting than the South Pars. Paleogeographic reconstruction of Arabian plate indicate that the Salman and it's adjacent fields are the result of salt tectonic. The predominance of shallower facies in the latter field could be related to this theory.