Types of shale lithofacies assemblage and its significance for shale oil exploration: A case study of Shahejie Formation in Boxing Sag
In order to realize the efficient development of lacustrine organic-rich shale oil reservoir in the lower sub-member of the third member of the Eocene Shahejie Formation and the upper sub-member of the fourth member of the Eocene Shahejie Formation in the Boxing Sag, Dongying depression, the geologi...
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Department of Petroleum Reservoir Evaluation and Development
2023-02-01
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| Series: | Youqicang pingjia yu kaifa |
| Subjects: | |
| Online Access: | https://red.magtech.org.cn/fileup/2095-1426/PDF/1675063853644-75254285.pdf |
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| Summary: | In order to realize the efficient development of lacustrine organic-rich shale oil reservoir in the lower sub-member of the third member of the Eocene Shahejie Formation and the upper sub-member of the fourth member of the Eocene Shahejie Formation in the Boxing Sag, Dongying depression, the geological data, such as thin sections, X-ray diffraction and the content of major and trace elements are analyzed. After the data analysis, the types of lithofacies and the evolution stage of sedimentary paleoenvironment are determined, and eight lithofacies assemblages are also divided based on the relationship between lithofacies and sedimentary environments. Then, the favorable lithofacies for shale oil exploration and development are determined based on the comparison of geological and engineering “sweet spot” parameters of different lithofacies assemblages. The results indicate that: ① Six lithofacies types of organic-rich laminated argillaceous limestone and limestone mudstone, organic-rich layered argillaceous limestone and limestone mudstone, organic-poor massive argillaceous limestone and calcareous mudstone are mainly developed in the study area; ② The sedimentary paleoenvironment with the characteristics of paleoclimate from arid to humid, little change in paleoredox, paleosalinity from high to low, and paleo-provenance from less to more exhibited eight evolutionary stages, corresponding to eight lithofacies assemblage types; ③ Lithofacies assemblage D and F, with high shale oil productivity, are the favorable in the Es3L and Es4U, respectively, and are in good agreement with the production practices. On the plane, the former is mainly distributed in the F159-F156-F160 well areas, and the latter is mainly distributed in FYP1-F116-F119 and F156-F159-F161 well area, which is a shale oil enrichment and high yield area in Boxing sag. |
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| ISSN: | 2095-1426 |