The Euphrates Graben is located in eastern Syria. The Upper Triassic Mulussa F Forma- tion sandstones serve as the primary reservoir intervals in the majority of the graben fields. The study ' s findings were based on core studies:petrographic examination of thin sections, scanning elec- tron microscope (SEM), imaging of backscatter scanning electron microscope (BSE), X-ray microprobe examinations, and carbon-oxygen stable isotope analysis of microfracture-filling cements. Three of the most common types of microfracture found in the investigated sandstones are intragranular or intrac- rystalline microfractures, grain boundary or grain-edge microfractures, and transgranular (crossing grains) microfractures. Sandstone microfractures that are open and free of secondary mineralization improve sandstone storage and permeability. However, microfractures that are cemented and filled with secondary mineralization reduce storage and permeability. Common siderite and pyrite cements were identified within the microfractures and the nearby sandstone matrix. Larger anhedral or euhe- dral siderites are thought to form during shallow burial diagenesis, whereas poikilotopic siderites are thought to form during deep burial diagenesis. Poikilotopic pyrite is believed to be a diagenetic cement, which is attributed to the reduction of iron oxides present in the sediments in the presence of hydrocar- bons. Microfractures reflect tectonic, overpressure, and diagenetic origins. Microfractures of tectonic origin are associated with folding and thrust activities over the Euphrates Graben area, and they were formed at the beginning of the Upper Triassic with siderite and pyrite cement equilibration tempera- tures of approximately 100–105 oC, and they continued forming from the middle to the end of the Up- per Triassic with cement equilibration temperatures of approximately 90–100 oC in conjunction with the first phase of the Euphrates Graben. Microfractures related to diagenetic and overpressure process- es are tension microfractures and were formed in compression settings during the Upper Triassic.

Ibrahem Yousef;Vladimir Morozov;Vladislav Sudakov;Ilyas Idrisov

Institute of Geology and Petroleum Technologies,Kazan Federal University,Kazan 420111,Russia

地球科学学刊（英文版）

[1]Ibrahem Yousef;Vladimir Morozov;Vladislav Sudakov;Ilyas Idrisov-.Microfracture Characterization in Sandstone Reservoirs:A Case Study from the Upper Triassic of Syria's Euphrates Graben)[J].地球科学学刊（英文版）,2022(04):901-915

Microfracture,Euphrates,Graben,Mulussa,Forma,microfracture,intrac,rystalline,anhedral,euhe,dral,siderites,poikilotopic,Poikilotopic,Microfractures

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