石油与天然气地质 ›› 2025, Vol. 46 ›› Issue (6): 1840-1859.doi: 10.11743/ogg20250607

• 油气地质 • 上一篇    下一篇

古老地层页岩气富集特征与勘探方向——来自中-上扬子地区寒武系的启示

聂海宽1,2,3(), 苏海琨4, 张珂4, 林拓5(), 刘忠宝1,2,3, 李沛1,2,3, 戎佳1,2,3, 王宇哲6   

  1. 1.页岩油气富集机理与高效开发全国重点实验室,北京 102206
    2.中国石化 页岩油气勘探开发重点实验室,北京 102206
    3.中国石化 石油勘探开发研究院,北京 102206
    4.中国地质大学(北京) 能源学院,北京 100083
    5.中国地质调查局 油气资源调查中心,北京 100083
    6.中国石油大学(北京) 地球科学学院,北京 102249
  • 收稿日期:2025-07-01 修回日期:2025-12-17 出版日期:2025-12-30 发布日期:2025-12-25
  • 通讯作者: 林拓 E-mail:niehk.syky@sinopec.com;everdeer@163.com
  • 第一作者简介:聂海宽(1982—),博士、研究员,非常规油气地质。E-mail:niehk.syky@sinopec.com
  • 基金项目:
    国家自然科学重点基金项目(42130803);中国石油化工股份有限公司科技部项目(P23132);中国石油化工股份有限公司科技部项目(P25144)

Enrichment characteristics and exploration targets of shale gas in ancient strata: Insights from the Cambrian shales in the Middle-Upper Yangtze region

Haikuan NIE1,2,3(), Haikun SU4, Ke ZHANG4, Tuo LIN5(), Zhongbao LIU1,2,3, Pei LI1,2,3, Jia RONG1,2,3, Yuzhe WANG6   

  1. 1.State Key Laboratory of Shale Oil & Gas Enrichment Mechanisms and Efficient Development,Beijing 102206,China
    2.Sinopec Key Laboratory of Shale Oil/Gas Exploration and Production,Beijing 102206,China
    3.Sinopec Petroleum Exploration and Production Research Institute,Beijing 102206,China
    4.School of Energy,China University of Geosciences (Beijing),Beijing 100083,China
    5.Oil and Gas Survey,China Geological Survey,Beijing 100083,China
    6.College of Geoscience,China University of Petroleum (Beijing),Beijing 102249,China
  • Received:2025-07-01 Revised:2025-12-17 Online:2025-12-30 Published:2025-12-25
  • Contact: Tuo LIN E-mail:niehk.syky@sinopec.com;everdeer@163.com

摘要:

四川盆地寒武系页岩气勘探取得重大突破,发现了目前全球地质时代最古老的页岩气藏。为揭示古老层系页岩气富集机理,以中-上扬子地区寒武系页岩为研究对象,结合勘探开发资料,系统分析了页岩岩相、储层、地化特征和气藏类型,重点研究了保存条件。研究表明:①研究区下寒武统发育富有机质[总有机碳含量(TOC) > 3%]和贫有机质(TOC < 1%)两类页岩,页岩有机质类型好(以Ⅰ-Ⅱ1型为主)、热演化程度高[等效镜质体反射率(EqVRo) > 3.0%],形成了自生自储型和运移聚集型两类页岩气藏。②优质储层和有机质热演化程度共同控制古老页岩气藏的形成。页岩优质储层的发育受控于成岩作用和生烃成孔演化的协同效应。③保存条件是古老页岩气富集的关键控制因素。德阳-安岳裂陷槽因构造稳定,形成了压力系数为1.6 ~ 2.0的超压,页岩气富集程度高。④建议优先在热演化程度相对较低(EqVRo < 3.5%)且保存条件良好的区域进行页岩气勘探。⑤寒武系古老页岩气资源潜力评价需重点关注超深层页岩气保存条件极限、优质储层形成机理、高-过成熟页岩生/排烃和滞留烃量定量表征等关键科学问题。

关键词: 优质储层, 保存条件, 资源潜力评价, 古老页岩气藏, 高-过成熟页岩, 寒武系, 四川盆地

Abstract:

Breakthroughs in the exploration of the Cambrian shale gas within the Sichuan Basin have contributed to the discovery of the most ancient shale gas reservoirs globally. To reveal the mechanisms governing the shale gas enrichment in ancient strata, we investigate the Cambrian shales in the Middle-Upper Yangtze region in this study. In combination with exploration and exploitation data, we systematically analyze the lithofacies, reservoir properties, geochemical characteristics, and gas play types of the shales, with particular emphasis placed on shale gas preservation conditions. The results indicate that the Lower Cambrian strata in the study area contain two types of shales, i.e., organic-rich and organic-lean shales, with total organic carbon (TOC) contents of greater than 3% and less than 1%, respectively. These shales contain organic matter with favorable kerogen types (dominated by types Ⅰ-Ⅱ1) and exhibit high thermal maturity, as indicated by an equivalent vitrinite reflectance (EqVRo) greater than 3.0%. Two types of shale gas plays are identified: self-sourced and migrated gas plays. The formation of the ancient shale gas plays is jointly controlled by the presence of high-quality reservoirs and the thermal maturity of organic matter, while the development of high-quality reservoirs is governed by the synergistic effects of diagenesis and hydrocarbon generation-induced pore formation. Preservation conditions play a key role in controlling the shale gas enrichment in ancient strata. The Deyang-Anyue rift trough demonstrates a high degree of shale gas enrichment attributable to its tectonic stability and resulting overpressure conditions with formation pressure coefficients ranging from 1.6 to 2.0. It is recommended that future shale gas exploration should focus on areas with both relatively low thermal maturity (EqVRo < 3.5%) and favorable preservation conditions. The resource potential evaluation of the ancient Cambrian shale gas should focus on several key scientific issues, including the preservation condition limits for ultra-deep shale gas, formation mechanisms of high-quality reservoirs, and the quantitative assessment of hydrocarbon generation, expulsion, and retention in highly- to over-mature shales.

Key words: high-quality reservoir, preservation condition, resource potential evaluation, ancient shale gas reservoir, highly- to over-mature shale, Cambrian, Sichuan Basin

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