石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (2): 353-364.doi: 10.11743/ogg20220209

• 油气地质 • 上一篇    下一篇

四川盆地上奥陶统五峰组-下志留统龙马溪组页岩储层特征与演化机制

王濡岳1,2,3(), 胡宗全1,2, 龙胜祥1, 杜伟1, 吴靖4, 邬忠虎5, 聂海宽1, 王鹏威1, 孙川翔1, 赵建华6   

  1. 1.中国石化 石油勘探开发研究院，北京 100083
    2.页岩油气富集机理与有效开发国家重点实验室，北京 102206
    3.中国石化 页岩油气勘探开发重点实验室，北京 102206
    4.山东科技大学 地球科学与工程学院，山东 青岛 266500
    5.贵州大学 土木工程学院，贵州 贵阳 550025
    6.中国石油大学（华东） 地球科学与技术学院，山东 青岛 266580
  • 收稿日期:2020-12-05 修回日期:2021-12-26 出版日期:2022-04-01 发布日期:2022-03-11
  • 第一作者简介:王濡岳（1990－），男，博士、高级工程师，非常规油气地质与油气勘探规划。E?mail： wry1990@vip.qq.com。
  • 基金项目:
    国家自然科学基金面上项目(41902134);中国石油化工股份有限公司科技部项目(P20046-1)

Reservoir characteristics and evolution mechanisms of the Upper Ordovician Wufeng-Lower Silurian Longmaxi shale， Sichuan Basin

Ruyue Wang1,2,3(), Zongquan Hu1,2, Shengxiang Long1, Wei Du1, Jing Wu4, Zhonghu Wu5, Haikuan Nie1, Pengwei Wang1, Chuanxiang Sun1, Jianhua Zhao6   

  1. 1.Petroleum Exploration and Production Research Institute，SINOPEC，Beijing 100083，China
    2.State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development，Beijing 102206，China
    3.Key Laboratory of Shale Oil and Gas Exploration & Production，SINOPEC，Beijing 102206，China
    4.College of Earth Science and Engineering，Shandong University of Science and Technology，Qingdao，Shandong 266500，China
    5.College of Civil Engineering，Guizhou University，Guiyang，Guizhou 550025，China
    6.School of Geosciences，China University of Petroleum （East China），Qingdao，Shandong 266580，China
  • Received:2020-12-05 Revised:2021-12-26 Online:2022-04-01 Published:2022-03-11

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摘要：

依据矿物岩石学、有机地球化学、储集空间、物性及含气性等特征，系统分析并探讨了上奥陶统五峰组-下志留统龙马溪组页岩储层特征、演化机制及其对页岩气勘探开发的影响，提出“生物硅钙控格架、协同演化促生孔、压力演化控保存”的页岩储层演化机制。研究结果表明：①岩相、有机孔载体类型及其赋存方式对有机孔的发育具有重要控制作用，硅质页岩大尺度有机质充填粒间孔（3 ~ 5 μm）发育程度高，最利于有机质大孔发育；粘土质页岩受TOC含量和有机质-粘土复合体结构影响，有机孔的孔径分布范围广、平均孔径大，但有机孔总量较小。②同生-早成岩阶段早期形成的生物石英、微生物白云石和黄铁矿等构成的刚性支撑格架利于原生孔隙的保存。中成岩阶段早期，有机酸的产生和消耗、不稳定矿物溶蚀/蚀变、粘土矿物转化和干酪根生油具有同步性，为生油期液态烃的充注与滞留提供了有利空间。中成岩晚期—晚成岩阶段，干酪根和滞留烃裂解生气、成孔和增压促进了有机孔与微裂缝的发育。③超压对压实作用的缓解利于有机孔形态与页岩物性的保持，对高应力敏感性粘土质页岩物性的保持影响显著，对底部高脆性矿物页岩段影响较低。盆内至盆缘构造的改造与泄压强度逐渐增大，底部硅质页岩物性变化不显著，上部粘土质页岩物性降低显著，封盖作用增强。

关键词: 岩相, 地层压力, 储层演化, 页岩气, 五峰组, 龙马溪组, 奥陶系, 志留系, 四川盆地

Abstract:

The characterization of the Upper Ordovician Wufeng - Lower Silurian Longmaxi shale in terms of mineralogy， organic geochemistry， storage space， physical properties and gas-bearing potential， is applied to discuss the evolutionary mechanisms and their influence on shale gas exploration and development， proposing a shale reservoir evolution mechanism of “framework development as controlled by biogenetic silica-calcite， pore generation as promoted by co-evolution， and pore preservation as controlled by pressure evolution”. The results show that： （1） lithofacies along with the type and occurrence of organic matters （organic pore carrier） plays an important role in controlling the development of organic pores. The intergranular pores （with a size of greater than 3-5 μm） filled with organic matters in the siliceous shales are highly developed， the most conducive to the development of organic macropores. The development of organic pores in argillaceous shales is affected by the TOC content and the structure of organo-clay complexes， and the organic pores are characterized by a wide range of distribution， large pore size on average， and small total number.（2） The rigid framework composed of bio-quartz， microbial dolomite and pyrite formed in the early of contemporaneous-early diagenetic stage contributes to the preservation of original pores. In the early stage of the middle diagenesis， the production and consumption of organic acids， unstable mineral dissolution， clay mineral transformation and oil generation from kerogens are synchronized， serving to provide spaces favorable for the charging and retention of liquid hydrocarbons during the oil generation period. From the late mesogenetic stage to the late diagenetic stage， gas generation， organic pore formation and pressure increase from cracking of kerogen and retained hydrocarbon jointly promote the development of organic pores and micro-fractures.（3） The compaction mitigation by overpressure allows the maintenance of organic pore morphology and shale physical properties. Its influence on highly stress-sensitive argillaceous shale at upper interval is obvious， while on the other hand， unapparent on highly brittle shale intervals at the bottom. With the tectonic modification and pressure relief intensity getting enhanced from the basinal center to edges， the physical properties of siliceous shale at the bottom largely remain the same， while the physical properties of the upper argillaceous shale become poor resulting in an enhanced sealing capacity.

Key words: lithofacies, formation pressure, reservoir evolution, shale gas, Wufeng Formation, Longmaxi Formation, Ordovician, Silurian, Sichuan Basin

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