›› 2019, Vol. 40 ›› Issue (4): 1-1.doi: 10.7657/XJPG20190402

   

Geological Characteristics, Resource Potential and Exploration Direction of Shale Oil in Middle-Lower Permian, Junggar Basin

ZHI Dongminga, SONG Yongb, HE Wenjunb, JIA Xiyub, ZOU Yangb, HUANG Liliangb   

  1. (PetroChina, a.Xinjiang Oilfield Company; b.Research Institute of Exploration and Development, Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China)
  • Online:2019-08-01 Published:1905-07-18

Abstract: The Middle-Lower Permian series, the most important source rocks in Junggar basin, are dominated by multi-source, fine-grained mixed sediments deposited in a terrestrial salty lake environment and have good conditions for shale oil generation. A shale oil province with the OOIP of one billion tons has been discovered in the Lucaogou formation of Jimsar sag. Based on the previous study results and combined with the available geological data, the paper systematically summarizes the geological characteristics of the favorable shale oil areas in the Middle-Lower Permian of the basin. Meanwhile, on the basis of benchmarking with the geological characteristics of the shale oil in the Lucaogou formation of Jimsar sag, the shale oil exploration potential in the Fengcheng formation of Mahu sag and the Pingdiquan formation of Wucaiwan-Shishugou sag is analyzed and the next exploration direction for the shale oil in the basin is discussed. The study results show that the multi-source fine-grained mixed sediments of shore-shallow lacustrine-semi-deep lacustrine facies in the Middle-Lower Permian strata of the basin are the high-quality source rocks where tight sweet-spot reservoirs are developed, and the reservoir combination is characterized by source rock-reservoir superposition and frequent interbed with each other vertically, which lays a foundation for shale oil accumulation in the Middle-Lower Permian strata. Typical terrestrial shale oil characteristics such as hydrocarbon mainly coming from neighboring source rocks, self generation as the complementary and in-situ accumulation can be obviously seen. The maximum proven resources of the shale oil in the basin is 27.25×108 t. The geological conditions of the Fengcheng shale oil in the Mahu sag are better than those of the Lucaogou shale oil in Jimsar sag, therefore, the Fengcheng formation in Mahu sag is considered as the next key area for shale oil exploration. The geological conditions of the Pingdiquan shale oil in Wucaiwan-Shishugou sag are relatively poor, and the shale oil here can only be considered as a prospect area for exploration. Additionally, the Luocaogou formation in the piedmont of Bogda Mountain and the Pingdiquan formation in the slope area of Fukang-Dongdaohaizi sag are the potential areas for shale oil exploration and at present comprehensive geological research should be performed to gain more geological understandings and to complete technical preparation work

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