Formation conditions and enrichment model of retained petroleum in lacustrine shale: A case study of the Paleogene in Huanghua depression, Bohai Bay Basin, China

被引:0
作者
Zhao X. [1 ]
Zhou L. [1 ]
Pu X. [1 ]
Jin F. [1 ]
Shi Z. [1 ]
Han W. [1 ]
Jiang W. [1 ]
Han G. [1 ]
Zhang W. [1 ]
Wang H. [1 ]
Ma J. [1 ]
机构
[1] PetroChina Dagang Oilfield Company, Tianjin
来源
Shiyou Kantan Yu Kaifa/Petroleum Exploration and Development | 2020年 / 47卷 / 05期
关键词
Bohai Bay Basin; Enrichment model; Huanghua depression; Kong; 2; Member; Lacustrine shale; Movable petroleum; Retained petroleum; Sha; 3; Shale oil;
D O I
10.11698/PED.2020.05.02
中图分类号
学科分类号
摘要
Compared with marine facies shale strata, lacustrine shale strata are more complicated in geological conditions, and thus more difficult to explore and develop. To realize economic exploration and development of lacustrine shale oil, the geological regularities of accumulation and high yield of retained movable petroleum in shale should be understood first. In this work, taking the shale strata of Kong 2 Member and Sha 3 Member in the Paleogene of Huanghua Depression in the Bohai Bay Basin as examples, based on the previous joint analysis results of over ten thousand core samples and the latest oil testing, production test and geochemical data of more than 30 horizontal wells, accumulation conditions and models of retained movable petroleum in lacustrine shale were studied comprehensively. The study shows that at moderate organic matter abundance (with TOC from 2% to 4%), shale strata have the best match between oil content and brittleness, and thus are rich in oil and good in fracability. Moderate ancient lake basin size and moderate sediment supply intensity are the internal factors leading to best coupling of organic matter abundance and brittle mineral content in the shale formation. Moderate thermal evolution maturity of Ro of 0.7%-1.0% (at burial depth of 3200 to 4300 m) is the interval where oil generation from thermal evolution and oil adsorption by kerogen in shale layers match best, and retained movable petroleum is high in proportion. Moderate diagenetic evolution stage (3200 to 4300 m in the middle diagenetic stage A) is conducive to the formation of a large number of dissolved pores and organic matter pores, which provide storage space for shale oil enrichment. Moderate development degree of natural fractures (without damaging the shale oil roof and floor sealing conditions) is conducive to the storage, seepage and preservation of shale oil. The research results have overthrown the general understanding that high organic matter abundance, high maturity, and high development degree of natural fractures are conducive to shale oil enrichment, and have guided the comprehensive evaluation of shale oil and gas sweet spots and well deployment in the second member of the Kongdian Formation in the Cangdong sag and the Shahejie Formation in the Qikou sag. Industrial development of the shale oil in Kong 2 Member of the Cangdong sag has made major breakthrough, and important signs of shale oil have been found in Sha 3 Member of the Qikou sag, demonstrating huge exploration potential of lacustrine shale oil. © 2020, The Editorial Board of Petroleum Exploration and Development. All right reserved.
引用
收藏
页码:856 / 869
页数:13
相关论文
共 47 条
[21]  
YANG Hua, LIANG Xiaowei, NIU Xiaobing, Et al., Geological conditions for continental tight oil formation and the main controlling factors for enrichment: A case from the Chang-7 Member, Triassic Yanchang Formation, Ordos Basin, NW China, Petroleum Exploration and Development, 44, 1, pp. 12-20, (2017)
[22]  
YAN Jihua, PU Xiugang, ZHOU Lihong, Et al., Naming method of fine-grained sedimentary rocks on basis of X-ray diffraction data, China Petroleum Exploration, 20, 1, pp. 48-54, (2015)
[23]  
ZHOU Lihong, PU Xiugang, DENG Yuan, Et al., Several issues in studies on fine-grained sedimentary rocks, Lithologic Reservoirs, 28, 1, pp. 6-15, (2016)
[24]  
ZHAO Xianzheng, PU Xiugang, ZHOU Lihong, Et al., A new method for lithology identification of fine grained deposits and reservoir sweet spot analysis: A case study of Kong 2 Member in Cangdong Sag, Bohai Bay Basin, China, Petroleum Exploration and Development, 44, 4, pp. 492-502, (2017)
[25]  
YAN Jihua, DENG Yuan, PU Xiugang, Et al., Characteristics and controlling factors of fine-grained mixed sedimentary rocks from the 2nd Member of Kongdian Formation in the Cangdong Sag, Bohai Bay Basin, Oil and Gas Geology, 38, 1, pp. 98-109, (2017)
[26]  
CHEN Shiyue, GONG Wenlei, ZHANG Shun, Et al., Fracture characteristics and main controlling factors of shales of the second member of Kongdian Formation in Cangdong Sag, Huanghua Depression, Geoscience, 30, 1, pp. 144-154, (2016)
[27]  
PU Xiugang, JIN Fengming, HAN Wenzhong, Et al., Sweet spots geological characteristics and key exploration technologies of continental shale oil: A case study of Member 2 of Kongdian Formation in Cangdong Sag, Acta Petrolei Sinica, 40, 8, pp. 997-1012, (2019)
[28]  
ZHAO Xianzheng, ZHOU Lihong, PU Xiugang, Et al., Favorable formation conditions and enrichment characteristics of lacustrine facies shale oil in faulted lake basin: A case study of Member 2 of Kongdian Formation in Cangdong Sag, Bohai Bay Basin, Acta Petrolei Sinica, 40, 9, pp. 1013-1029, (2019)
[29]  
ZHAO Xianzheng, ZHOU Lihong, PU Xiugang, Et al., Exploration breakthroughs and geological characteristics of continental shale oil: A case study of the Kongdian Formation in the Cangdong Sag, China, Marine and Petroleum Geology, 102, pp. 544-556, (2019)
[30]  
ZHAO Xianzheng, PU Xiugang, ZHOU Lihong, Et al., Typical geological characteristics and exploration practices of lacustrine shale oil: A case study of the Kong-2 member strata of the Cangdong Sag inthe Bohai Bay Basin, Marine and Petroleum Geology, 113, (2020)