Characteristics of Diagenesis  and Diagenetic Facies of Permian Clastic Reservoir in Northwest Margin of Junggar Basin

Key words: 
• the northwest edge of Junggar Basin /
• Permian clastic

Abstract: The Permian sandy conglomerates in Kebai area is one of the most important petroleum reservoir rocks  in Junggar Basin. According to the result of the polarized microscope analysis of the diagenesis, authigenic mineral assemblage, pore characteristics of the clastic reservoir, and the study of scanning electron microscope(SEM), test of porosity and permeability, mud logging and well logging data, the type of rock and the diagenesis of Permian sandy conglomerates in  the study area is studied. It suggests that the factors of influencing reservoir property in the study area are compaction, cementation  and dissolution. In terms of the research on stage and characteristics of diagenesis, the Permian sandy conglomerate reservoirs in the study area are divided into seven diagenetic facies: 1) high maturestrong dissolution facies, 2) high maturestrong cementation facies, 3) high maturemiddle cementationmiddle dissolution facies, 4) high matureweak compression facies, 5) high maturestrong compression facies, 6) low matureweak compression facies,7) low maturestrong compression facies. Then, the conditions of diagenesis facies, the feature of diagenesis, the environment of diagenesis, model of diagenesis and evolutionary sequence of diagenesis are concluded and summarized. Furthermore, the reservoir properties of sandy conglomerate of different diagenesis facies is summarized. The main lithofacies belt and sedimentary facies zone of high quality reservoir development zones is  predicted and described .