石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (1): 1-25.doi: 10.11743/ogg20220101

• 油气地质 • 上一篇    下一篇

中国海、陆相页岩层系岩相组合多样性与非常规油气勘探意义

黎茂稳1,2(), 马晓潇1,2, 金之钧1,2, 李志明1,2, 蒋启贵1,2, 吴世强3, 李政4, 徐祖新5   

  1. 1.页岩油气富集机理与有效开发国家重点实验室, 江苏 无锡 214126
    2.中国石化 石油勘探开发研究院, 北京 100083
    3.中国石化 江汉油田分公司, 湖北 武汉 430223
    4.中国石化 胜利油田分公司, 山东 东营 257015
    5.中国石化 勘探分公司, 四川 成都 610041
  • 收稿日期:2021-08-19 修回日期:2021-11-25 出版日期:2022-02-01 发布日期:2022-01-28
  • 第一作者简介:黎茂稳(1962—),男,博士、教授级高级工程师,石油地质。E?mail: limw.syky@sinopec.com
  • 基金项目:
    国家自然科学基金项目(42090022)

Diversity in the lithofacies assemblages of marine and lacustrine shale strata and significance for unconventional petroleum exploration in China

Maowen Li1,2(), Xiaoxiao Ma1,2, Zhijun Jin1,2, Zhiming Li1,2, Qigui Jiang1,2, Shiqiang Wu3, Zheng Li4, Zuxin Xu5   

  1. 1.State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Wuxi, Jiangsu 214126, China
    2.Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China
    3.Jianghan Oilfield Company, SINOPEC, Wuhan, Hubei 430223, China
    4.Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257015, China
    5.Exploration Company, SINOPEC, Chengdu, Sichuan 610041, China
  • Received:2021-08-19 Revised:2021-11-25 Online:2022-02-01 Published:2022-01-28

摘要:

富有机质细粒沉积岩相组合和有机相之间存在着很强的相关性,富碳酸盐细粒沉积岩相组合以Ⅰ-S或Ⅱ-S型有机相为主,长英质页岩相组合多数为Ⅱ型有机相,而富粘土质页岩相组合的有机相多为Ⅲ/Ⅳ型有机质。因此,全岩矿物X衍射分析既可用于研究细粒沉积岩相与沉积环境,也可提供有机质类型、烃类产物特征、岩石力学性质和可压性等重要参考信息。在北美和四川盆地海相页岩对比分析的基础上,以中国主要陆相页岩层系为研究对象,利用全岩矿物X衍射分析,结合岩心观察、薄片鉴定、总有机碳含量(TOC)分析等多种手段,开展岩相和有机相类型识别及岩相组合特征和不同页岩层系差异性分析,并探讨它们对非常规页岩油气勘探的指导意义。研究结果表明,中国陆相湖盆沉积类型多样,陆相盆地拗陷期淡水-微咸水湖泊页岩层系以贫碳酸盐矿物的粘土质-长英质页岩相组合为主;而陆相盆地裂陷期咸化、碱化湖泊沉积以碳酸盐质页岩相组合和含碳酸盐的粘土质-长英质页岩相组合为主,各种陆相细粒沉积体系均以相带变化快、岩性-岩相复杂、储-盖组合样式多变为特征。中国陆相细粒沉积岩相的非均质性和岩相组合的多样性,带来了陆相页岩油气“甜点”类型的多样性;不同岩相组合对应的有机相存在显著差异,有机质的差异演化又带来了不同岩相中烃类赋存状态的差异性。这些分析结果证实,每套陆相页岩都具有各自的地质特点。细粒沉积岩相和有机相组合的多样性和差异性,揭示了陆相页岩油气“甜点”和资源分类评价的必要性。

关键词: 全岩矿物X衍射分析, 有机相, 沉积微相分析, 细粒沉积岩, 陆相页岩油, 中国

Abstract:

There is a strong correlation between the lithofacies and organofacies of fine-grained organic matter-rich sedimentary rocks,where the carbonate-, quartz-feldspar- and clay mineral-rich lithofacies often show high affinity respectively with type I-S/II-S,I/II and III/IV organic facies. Hence, whole rock mineral X-ray diffraction analysis (XRD) represents a straightforward and effective method to predict the lithofacies, organic matter type, depositional environment, hydrocarbon characteristics, and rock mechanics of geological samples concerned. Based on a thorough review of marine shale data from North America and the Sichuan Basin, a large collection of lacustrine shales from major non-marine sedimentary basins in China were characterized by whole-rock mineral XRD, core observation, thin section analysis and total organic carbon (TOC) measurement. The aims are to classify the lithofacies and organofacies, identify the key difference in lithofacies assemblages, and discuss their implication for unconventional shale oil and gas exploration. The results indicate that lacustrine shales in sedimentary basins in China were deposited in various tectonostratigraphic settings. In general, the fine-grained sediments in freshwater-brackish water lakes in sag stage are dominated by clay-quartz with minor carbonate, whereas the saline and alkaline lacustrine sediments in rift stage consist of carbonate or clay-quartz with carbonate minerals. The sedimentary systems of fine-grained lacustrine deposits are characterized by rapid facies change, complex lithologies, and variable reservior-caprock combinations. Thus, the strong heterogeneity in the lithofacies and their combinations often lead to multiple types of shale oil “sweetspots”; as different lithofacies correspond to varying organofacies, the variation in the thermal behaviors of different organofacies contributes to the change in the states of hydrocarbon occurrence among the various lithofacies combinations. These results confirm that every shale is unique. Therefore, the variation in lithofacies and organofacies of the fine-grained sediments indicates that it is essential to use quantitative and objective parameters in classifying the “sweetspots” and hydrocarbon states of occurrence in order to make the credible assessment of shale oil resources.

Key words: whole rock XRD analysis, organofacies, microfacies analysis, fine-grained sedimentary rocks, Lacustrine shale oil, China

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