Special Oil & Gas Reservoirs ›› 2023, Vol. 30 ›› Issue (5): 42-49.DOI: 10.3969/j.issn.1006-6535.2023.05.006

• Geologic Exploration • Previous Articles     Next Articles

Reservoir Space and Physical Characteristics of Shale Oil with Different Lithologies

Zhou Zhijun1, Zhang Guoqing1, Cui Chunxue2, Wang Jingyi3, Wang Juan4   

  1. 1. Key Laboratory for Improving Oil and Gas Recovery (Northeast Petroleum University), Ministry of Education, Daqing, Heilongjiang 163318, China;
    2. Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;
    3. PetroChina Daqing Oilfield Co., Ltd., Daqing, Heilongjiang 163318, China;
    4. COSL Oilfield Production Division, Tianjin 300459, China
  • Received:2023-03-26 Revised:2023-06-26 Online:2023-10-25 Published:2023-12-25

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Abstract: In view of the lack of deep understanding of the reservoir characteristics of the Shahejie Formation in the Jiyang Depression, it affects the exploration and development of shale oil. Taking key coring wells of the lower sub-section of the Member 3 and the upper sub-section of the Member 4 of the Paleogene Shahejie Formation of in the Jiyang Depression as the study object, X-Ray Diffraction was used to determine the mineral composition of shale reservoirs, and the shale was classified into mudstone Shale, limestone and dolomite, the mudstone in the lower sub-section of the Member 3 of the Shahejie Formation is relatively developed, and dolomite in the upper sub-section of the Member 4 of the Shahejie Formation is relatively developed; the reservoir space and pore size of shale with different lithologies were quantitatively described with the scanning electron microscopy, and the predominant lithology of shale reservoirs was analyzed. The results of the study show that the medium to large pores were developed in dolomite, and the oil are mainly occurred in the dolomite intergranular micropores and dissolved pores; the medium to small pores were developed in mudstone, and the oil were mainly filled in the intergranular micropores and intergranular micro-fractures; the small pores were developed in limestone, and the oil were mainly occurred in the intergranular micropores and locally in the dissolved pores; the dominant lithologies of shale reservoirs were, in order of preference: dolomite, mudstone and limestone; the oil content and oil test data of different lithologies showed that the upper sub-section of the Member 4 of Shahejie Formation in the Jiyang Depression is a high-production oil section, and it can be determined as the “sweet spot”reservoir of the Shahejie Formation in the Jiyang Depression. The study results have guidance significance to the exploration and development of shale oil in Jiyang Depression.

Key words: Jiyang Depression, shale oil, different lithologies, reservoir space, physical characteristics

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