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'''By Zhi Yang, Research Institute of Petroleum Exploration and Development (RIPED), PetroChina, China'''

'''By Zhi Yang, Research Institute of Petroleum Exploration and Development (RIPED), PetroChina, China'''

Both tight and shale oil occur in the shale strata of the Permian Junggar Basin. The early-middle Permian formations in the Junggar Basin are in sedimentary environments of saline lake basins formed after a section of sea was closed off. Lacustrine-facies dark [[mudstone]] and dolomite interbedded deposits are primarily found in these basins. Organic-rich shales are mainly distributed in the Lower Permian Fengcheng Formation in the Mahu Sag, the Middle Permian Lucaogou Formation in the Jimsar Sag, and the Middle Permian Pingdiquan Formation in the Kelameili Front, in layers of large thickness and wide plane distribution; these are the oldest continental shale series in China and the most important oil source rocks in the Junggar Basin. China's oldest continental shale is in the Permian strata of the Junggar Basin, which are composed of fine sediments in an offshore saline lake basin<ref name=Kng2012>Kuang, L., Y. Tang, D. Lei, Q. Chang, M. Ouyang, L. Hou, and D. Liu, 2012, Formation conditions and exploration potential of tight oil in the Permian saline lacustrine dolomitic rock, Junggar Basin, NW China: Petroleum Exploration and Development Online, vol. 39, no. 6, p. 657–667.</ref> (Zhang et al., 2007) and have abundant petroleum resources.  

Both tight and shale oil occur in the shale strata of the Permian Junggar Basin. The early-middle Permian formations in the Junggar Basin are in sedimentary environments of saline lake basins formed after a section of sea was closed off. Lacustrine-facies dark [[mudstone]] and dolomite interbedded deposits are primarily found in these basins. Organic-rich shales are mainly distributed in the Lower Permian Fengcheng Formation in the Mahu Sag, the Middle Permian Lucaogou Formation in the Jimsar Sag, and the Middle Permian Pingdiquan Formation in the Kelameili Front, in layers of large thickness and wide plane distribution; these are the oldest continental shale series in China and the most important oil source rocks in the Junggar Basin. China's oldest continental shale is in the Permian strata of the Junggar Basin, which are composed of fine sediments in an offshore saline lake basin<ref name=Kng2012>Kuang, L., Y. Tang, D. Lei, Q. Chang, M. Ouyang, L. Hou, and D. Liu, 2012, Formation conditions and exploration potential of tight oil in the Permian saline lacustrine dolomitic rock, Junggar Basin, NW China: Petroleum Exploration and Development Online, vol. 39, no. 6, p. 657–667.</ref><ref>Zhang, Y., X. Qi, X. Cheng, and Z. Luo, 2007, Approach to sedimentary environment of late carboniferous-Permian in Junggar Basin: Xinjiang Petroleum Geology, vol. 28, no. 6, p. 673–675.</ref>.  

The Middle Permian Lucaogou Formation in the eastern Junggar Basin contains globally rare organic-rich shale, and acts as both source and reservoir of shale oil. It is characterized by superimposed thin layers, large thickness, overall oiliness, and continuous distribution<ref name=Yng2018>Yang, Z., L. Hou, S. Lin, X. Luo, L. Zhang, S. Wu, and J. Cui, 2018, Geologic characteristics and exploration potential of tight oil and shale oil in Lucaogou Formation in Jimsar sag: China Petroleum Exploration, vol. 23, no. 4, p. 76–85.</ref>. The Jimsar Sag is a representative sag containing oil-rich shale. Recently, significant progress was made in the development of petroleum resources in the Lucaogou Formation shale in the Jimsar Sag. SRV fracturing was used in horizontal wells and two continuously distributed “sweet sections” were discovered<ref name=Kng2012 /><ref name=Yng2018 /><ref name=Yng2019a>Yang, Z., C. Zou, S. Wu, S. Lin, S. Pan, X. Niu, G. Men, et. al, 2019a, Formation, distribution and resource potential of the “sweet areas (sections)” of continental shale oil in China: Marine and Petroleum Geology, vol. 102, p. 48–60.</ref><ref name=Ymg2019b>Yang, Z., C. Zou, L. Hou, S. Wu, S. Lin, X. Luo, Z. Zhao, J. Cui, and S. Pan, 2019b. Division of fine-grained rocks and selection of “sweet sections” in the oldest continental shale in China: Taking the coexisting combination of tight and shale oil in the Permian Junggar Basin: Marine and Petroleum Geology, vol. 109, p. 339–348.</ref>. Using abundant experimental data from the Lucaogou Formation shales in the Jimsar Sag and by analyzing the source rocks, reservoirs, and oil-bearing layers, lithofacies distribution and lithology division were studied, with the aim to arrive at new bases for selecting “sweet sections”.

The Middle Permian Lucaogou Formation in the eastern Junggar Basin contains globally rare organic-rich shale, and acts as both source and reservoir of shale oil. It is characterized by superimposed thin layers, large thickness, overall oiliness, and continuous distribution<ref name=Yng2018>Yang, Z., L. Hou, S. Lin, X. Luo, L. Zhang, S. Wu, and J. Cui, 2018, Geologic characteristics and exploration potential of tight oil and shale oil in Lucaogou Formation in Jimsar sag: China Petroleum Exploration, vol. 23, no. 4, p. 76–85.</ref>. The Jimsar Sag is a representative sag containing oil-rich shale. Recently, significant progress was made in the development of petroleum resources in the Lucaogou Formation shale in the Jimsar Sag. SRV fracturing was used in horizontal wells and two continuously distributed “sweet sections” were discovered<ref name=Kng2012 /><ref name=Yng2018 /><ref name=Yng2019a>Yang, Z., C. Zou, S. Wu, S. Lin, S. Pan, X. Niu, G. Men, et. al, 2019a, Formation, distribution and resource potential of the “sweet areas (sections)” of continental shale oil in China: Marine and Petroleum Geology, vol. 102, p. 48–60.</ref><ref name=Ymg2019b>Yang, Z., C. Zou, L. Hou, S. Wu, S. Lin, X. Luo, Z. Zhao, J. Cui, and S. Pan, 2019b. Division of fine-grained rocks and selection of “sweet sections” in the oldest continental shale in China: Taking the coexisting combination of tight and shale oil in the Permian Junggar Basin: Marine and Petroleum Geology, vol. 109, p. 339–348.</ref>. Using abundant experimental data from the Lucaogou Formation shales in the Jimsar Sag and by analyzing the source rocks, reservoirs, and oil-bearing layers, lithofacies distribution and lithology division were studied, with the aim to arrive at new bases for selecting “sweet sections”.