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Fine-grained rocks(FGR) are the important source rocks and reservoirs of shale hydrocarbon which is the prospect hotspot at present. Widely distributed fine-grained sediments(FGS) of the upper fourth member of Shahejie Formation in Dongying depression are taken as an example to study the space-time evolution and controlling factor of FGS in this paper. Based on the analysis of well cores, thin sections, inorganic and organic geochemistry indicators, FGR are divided into 7 types of lithofacies. Through the study of ‘point-line-plane’, this study shows that FGS has the characteristics of rhythum, diversity and succession. The first stage is characterized by clayey FGS(massive claystone). The second stage is characterized by carbonate FGS(low-TOC laminated limestone) and dolomitic FGS(dolomitic-silty shale) formed by transgression. The third stage is characterized by organic-rich carbonate FGS(middle/high-TOC laminated limestone) distributed in cycle. The fourth stage is characterized by FGS mixed carbonate and siliciclastic sediments(calcareous-silty shale). A variety of space-time evolution of FGS are controlled by multiple factors including tectonism, climate and lake conditions.
Fine-grained rocks (FGR) are the important source rocks and reservoirs of shale hydrocarbons which is the prospect hotspot at present. Widely distributed fine-grained sediments (FGS) of the upper fourth member of Shahejie Formation in Dongying depression are taken as an example To study the space-time evolution and controlling factor of FGS in this paper. Based on the analysis of well cores, thin sections, inorganic and organic geochemistry indicators, FGR are divided into 7 types of lithofacies. Through the study of ’point-line -plane ’, this study shows that FGS has the characteristics of rhythum, diversity and succession. The first stage is characterized by clayey FGS (massive claystone). The second stage is characterized by carbonate FGS (low-TOC laminated limestone) and dolomitic FGS (dolomitic-silty shale) formed by transgression. The third stage is characterized by organic-rich carbonate FGS (middle / high-TOC laminated limestone) distributed in cycle. The fourth stage is characterized b y FGS mixed carbonate and siliciclastic sediments (calcareous-silty shale). A variety of space-time evolution of FGS are controlled by multiple factors including tectonism, climate and lake conditions.