Authors
1
Student of Doctora, , Department of Geology, Faculty of Science, Islamic Azad University, Zahedan Branch, Zahedan, Iran
2
Assistant Professor, Department of Geology, Faculty of Science, Islamic Azad University, Zahedan Branch, Zahedan, Iran
3
, Assistant Professor, Department of Geology, Faculty of Science, Islamic Azad University, Zahedan Branch, Zahedan, Iran
Abstract
The Dalan Formation is a carbonate sequence of Upper Permian age, which was widely deposited in Persian regions. Dalan Formation has been studied in the underground section of Kish 2, 1 and B2 wells of Kish Island gas field. Petrographic studies and facies analysis led to the identification of 12 microfacies deposited in a single-slope carbonate ramp and in 4 sedimentary sub-environments, including intertidal, lagoon, bariier and open sea areas. The important diagenesis processes that have affected the carbonate rocks of the Dalan Formation include micritization, cementation, anhydritization, compression, dolomitization and dissolution. Diagenesis minerals obtained in these deposits include three types of dolomite with replacement texture, two types of dolomite with cement texture, two types of anhydrite and two groups of calcite cement. Replacement type dolomite generally improves the reservoir quality and anhydrite reduces the reservoir quality by creating a layer by creating an obstacle in the path of hydrocarbon movement. Intercrystalline, interparticle and sheared porosity is the best type of porosity in the whole rock. The reservoir rocks were divided into 4 categories (RRTs-1 to RRTs-4) based on the analysis of the drilling core (SCAL data) and the description of thin sections. The first category is the best reservoir rock for storing and producing hydrocarbons, and the quality reservoir decreases towards the fourth category. According to the available data, the sedimentary environment cannot completely create the necessary conditions for the formation of reservoir-quality rocks, but mainly the final diagenesis along with diapirism determines the reservoir or non-reservoir formation.
Keywords
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