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| 扬子区西南缘奥陶纪末—志留纪初笔石生物地层对比及意义 |
| 张娣,刘伟,周业鑫,牟必鑫,周志,郝景宇,赵安坤,陆俊泽,余谦 |
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(1. 中国地质调查局成都地质调查中心, 四川 成都 610081;
2. 自然资源部沉积盆地与油气资源重点实验室, 四川 成都 610081;
3. 四川省煤田地质工程勘察设计研究院, 四川 成都 610072;
4. 中国地质调查局油气资源调查中心, 北京 100083;
5. 中国石油化工股份有限公司勘探分公司, 四川 成都 610041) |
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| 摘要: |
| 利用扬子西南缘天全、汉源、甘洛、布拖、金阳、永善、绥江、大关地区五峰组—龙马溪组重点剖面露头点和钻井岩心资料，通过笔石生物地层划分，建立了五峰组—龙马溪组黑色页岩的等时地层格架。通过对比纵横向黑色页岩的TOC含量、沉积厚度、优质页岩厚度等数据变化，探讨笔石带的分布与沉积环境、优质页岩的关系。结果表明，各剖面和钻井中WF2—LM4笔石带优质页岩普遍发育。其中布拖、金阳靠近康滇古陆边缘的地区，LM5笔石带、LM6笔石带岩石地层明显增厚；永善—绥江云永地2井、新地2井、绥江B井等地区，笔石带分布和沉积环境相似，优质页岩沉积上界由LM4笔石带逐步上延至LM6笔石带。五峰组—龙马溪组优质页岩在靠近康滇古陆一侧沉积时限为WF2—LM4及以下笔石带，远离古陆一侧沉积时限呈逐渐变长的趋势。天全大井坪、汉源轿顶山一带WF2—LM5笔石带优质页岩发育，轿顶山地区岩石地层厚度明显减薄，天全大井坪地区明显增厚，受特殊环境影响可能仍具有良好的勘探潜力。研究成果对扬子西南缘页岩气沉积有利区优选提供了依据。 |
| 关键词: 扬子西南缘 奥陶纪末—志留纪初 笔石生物地层 页岩气 勘探启示 |
| DOI：10.19826/j.cnki.1009-3850.2022.06005 |
| 附件 |
| 投稿时间：2022-01-02修订日期：2022-05-27 |
| 基金项目:第二次青藏高原综合科学考察(2019QZKK0704, 2019QZKK0708)；国家自然科学基金(41807333)；中国地质调查局地质调查项目(DD20160176，DD20190080)；成都地质调查中心“刘宝珺院士基金”；中石化项目（35450003-20-ZC0613-0003） |
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| Biostratigraphic correlation of graptolites from Late Ordovician to Early Silurian on the southwestern margin of the Yangtze region |
| ZHANG Di, LIU Wei, ZHOU Yexin, MU Bixin, ZHOU Zhi, HAO Jingyu, ZHAO Ankun, LU Junze, YU Qian |
(1. Chengdu Center, China Geological Survey, Chengdu 610081, China;
2. Key Laboratory of Sedimentary Basins and Oil and Gas Resources, Ministry of Natural Resources, Chengdu 610081, China;
3. Sichuan Institute of Coal Field Geological Engineering Exploration and Designing, Chengdu 610072, China;
4. Oil and Gas Survey Center, China Geological Survey, Beijing 100083, China;
5. Sinopec Exploration Company, Chengdu 610041, China) |
| Abstract: |
| Based on the data of graptolite biozonations of section outcrops and drilling cores in the southwestern margin of Yangtze region, the isochronous stratigraphic framework of the Wufeng-Longmaxi Formation black shales is established. By comparing the horizontal and verticalchanges of black shales' TOC, the thickness of depositions, and the thickness of high-quality shales, the relationship between the graptolite biozones and the depositional environments of high-quality shales is defined. The results show that the high-quality shales in Butuo, Jinyang, Ganluo, and Well Yunyongdi 3 are below graptolite biozones of WF2-LM4 while strata of LM5-LM6 are obviously thickened. In Daguan-Suijiang area, Well Yunyongdi 2, Well Xindi 2, and Well Suijiang B, the graptolite biozones and sedimentary environment are stable, but their exploration effects are obviously different. The highest level of high-quality shale is of the LM4 graptolite biozone, which may extend to the LM6 graptolite biozone gradually. Beside the Kangdian Oldland, high-quality Wufeng-Longmaxi black shales range from WF2 to LM4 graptolite biozones while away from the the Kangdian Oldland the black shales possess a higher horizon. High-quality shale of WF2-LM5 graptolite biozones well developed in Dajingping and Jiaodingshan areas. The thickness of the strata in the Jiaodingshan area of Hanyuan is obviously thinner, but it becomes thicker in the Dajingping area of Tianquan, indicating a special geological setting. This research results provide a basis for the favorable areas of shale gas exploration in the southwestern margin of the Yangtze region. |
| Key words: southwestern margin of Yangtze region Late Ordovician to Early Silurian graptolite biostratigraphy shale gas explorational implication |