湖相泥岩、页岩的沉积环境和特征对比——以鄂尔多斯盆地延长组7段为例

doi:10.11743/ogg20180310

摘要/Abstract

摘要：

泥质岩可分为泥岩和页岩两大类，二者在成因机制、有机质含量及赋存状态、矿物组成等方面存在显著差异。开展湖相泥岩、页岩的分布特征研究以及其差异特征的对比，有助于建立富有机质页岩的沉积模式。鄂尔多斯盆地三叠系延长组7段（长7段）沉积时期为湖盆发展的鼎盛时期，湖盆中心沉积了大套的泥岩和页岩。该文应用典型剖面分析、岩心-薄片观察、地球化学分析等手段揭示了长7段泥岩和页岩在分布特征、地球化学特征、岩石组分、组构、主微量元素等五方面的差异。①分布特征：泥岩和页岩互补分布，泥岩主要发育在三角洲前缘、深湖-浊积岩相和半深湖相，页岩主要沉积于深湖相；②组构特征：页岩有页理，有机质顺层分布，泥岩无页理，有机质分散分布；③岩石组分：页岩更富集黄铁矿，是泥岩的11倍，泥岩的白云岩、菱铁矿含量更高；④有机地球化学指标：页岩TOC平均含量为6.6%，是泥岩的3倍，S₁值平均含量为3.1 mg/g，是泥岩的2.5倍；⑤主微量元素：页岩中U，Th，Mo，Co，Ni等微量元素显著高于泥岩且U/Th，V/Cr和P/Al的比值较高，泥岩中Ti/Al和K/Al比值更高。综合分析，鄂尔多斯盆地长7泥岩和页岩的形成主要受沉积相带、湖水深度和湖盆生产力控制。页岩沉积时，水体生产力更高，离物源更远，水体更为缺氧。

关键词: 长7段, 富有机质页岩, 沉积环境, 泥岩, 页岩, 鄂尔多斯盆地

Abstract:

Argillaceous rocks(or argillite)can be subdivided into two categories,mudstone and shale,which differ significantly in genetic mechanism,content of organic matters and mode of occurrence,constituent minerals,etc.A study on distribution patterns of lacustrine mudstone and shale as well as comparisons of their distinguished characteristics would be of great help in building up an organic-rich shale depositional model.The Chang 7 Member of the Yachang Formation is represented by a large set of mudstone and shale,which was deposited in the period of maximum lake depth of the Ordos Basin during the Triassic.Their differences,which are ascribed into five aspects (distribution pattern,geochemical cha-racteristics,rock composition,fabric,and main and trace elements),have been disclosed by typical vertical profile analysis,core-thin section observation,geochemical analysis,etc.That is,(1)distribution pattern:mudstone and shale are complimentarily deposited,with mudstone mainly deposited in delta front,deep-lacustrine-turbidite facies,and semi-deep lacustrine facies,while shale mainly in deep lacustrine facies;(2)fabric feature:shale is characterized by laminae and organic matters occurring along layers,while mudstone exhibits no laminae and its organic matters scattered;(3)rock composition:shale is rich in pyrite,eleven times the content of mudstone pyrite,whereas mudstone holds more dolomite and si-derite;(4)organic geochemistry indices:the TOC of shale with an average of 6.6%,is three times as much as that of mudstone,and the value of S₁ averaging at 3.12 mg/g,is 2.5 times that of mudstone;(5)main and trace elements:shale is significantly higher in trace elements content like U,Th,Mo,Co,Ni,and in ratios like U/Th,V/Cr and P/Al than those in mudstone,while Ti/Al and K/Al ratios are higher in mudstone.In a word,the formation of mudstone and shale in the Chang 7 Member is mainly controlled by sedimentary facies,lake depth,and lake basin productivity.Shale is deposited further away from sediment source area with higher productivity and less oxygen in water.

Key words: Chang 7 Member, organic-rich shale, depositional environment, mudstone, shale, Ordos Basin

中图分类号:

TE121.3

刘群,袁选俊,林森虎,等. 湖相泥岩、页岩的沉积环境和特征对比——以鄂尔多斯盆地延长组7段为例[J]. 石油与天然气地质, 2018, 39(3): 531-540. doi: 10.11743/ogg20180310 Liu Qun,Yuan Xuanjun,Lin Senhu,et al. Depositional environment and characteristic comparison between lacustrine mudstone and shale: A case study from the chang 7 Member of the Yanchang Formation,Ordos Basin[J]. Oil & Gas Geology, 2018, 39(3): 531-540. doi: 10.11743/ogg20180310

参考文献

[1] 邹才能,朱如凯,吴松涛,等.常规与非常规油气聚集类型,特征,机理及展望-以中国致密油和致密气为例[J].石油学报,2012,33(2):173-187. Zou Caineng,Zhu Rukai,Wu Songtao,et al.Types,characteristics,genesis and prospects of conventional and unconventional hydrocarbon accumulations:taking tight oil and tight gas in China as an instance[J].Acta Petrolei Sinica,2012,33(2):173-187.
[2] 邹才能,杨智,崔景伟,等.页岩油形成机制,地质特征及发展对策[J].石油勘探与开发,2013,40(1):14-26. Zou Caineng,Yang Zhi,Cui Jingwei,et al.Formation mechanism,geological characteristics,and development strategy of nonmarine shale oil in China[J].Petroleum Explanation and Development,2013,40(1):14-26.
[3] 王志刚.涪陵页岩气勘探开发重大突破与启示[J].石油与天然气地质,2015,36(1):1-6. Wang Zhigang.Breakthrough of Fuling shale gas exploration and development and its inspiration[J].Oil & Gas Geology,2015,36(1):1-6.
[4] 卢双舫,陈国辉,王民,等.辽河坳陷大民屯凹陷沙河街组四段页岩油富集资源潜力评价[J].石油与天然气地质,2016,37(1):8-14. Lu Shuangfang,Chen Guohui,Wang Min,et al.Potential evaluation of enriched shale oil resource of Member 4 of the Shahejie Formation in the Damintun Sag,Liaohe Depression[J].Oil & Gas Geology,2016,37(1):8-14.
[5] 龙胜祥,曹艳,朱杰,等.中国页岩气发展前景及相关问题初探[J].石油与天然气地质,2016,37(6):847-853. Long Shengxiang,Cao Yan,Zhu Jie.A preliminary study on prospects for shale gas industry in China and relevant issues[J].Oil & Gas Geology,2016,37(6):847-853.
[6] Macquaker,Joe HS,Adams A E.Maximizing information from fine-grained sedimentary rocks:an inclusive nomenclature for mudstones[J].Journal of Sedimentary Research,2003,73(5):735-744.
[7] 孟志勇.四川盆地涪陵地区五峰组-龙马溪组含气页岩段纵向非均质性及其发育主控因素[J].石油与天然气地质,2016,37(6):838-846. Meng Zhiyong.Vertical heterogeneity and its controlling factors of the gas shale in the Wufeng-Longmaxi Fms in Fuling area,the Sichuan Basin[J].Oil & Gas Geology,2016,37(6):838-846.
[8] 彭丽,陆永潮,彭鹏,等.渤海湾盆地渤南洼陷沙三下亚段泥页岩非均质性特征及演化模式-以罗69井为例[J].石油与天然气地质,2017,38(2):219-229. Peng Li,Lu Yongchao,Peng Peng,et al.Heterogeneity and evolution model of the Lower Shahejie Member 3 mud-shale in the Bonan Subsag,Bohai Bay Basin:An example from Well Luo 69[J].Oil & Gas Geology,2017,38(2):219-229.
[9] 林森虎,袁选俊,杨智.陆相页岩与泥岩特征对比及其意义-以鄂尔多斯盆地延长组7段为例[J].石油与天然气地质,2017,38(3):517-523. Lin Senhu,Yuan Xuanjun,Yang Zhi.Comparative study on lacustrine shale and mudstone and its significance:A case from the 7^th Member of Yanchang Formation in the Ordos Basin[J].Oil & Gas Geology,2017,38(3):517-523.
[10] 魏琳,许文国,杨仓,等.页岩层序划分的界面沉积标志及地球化学指示[J].石油与天然气地质,2017,38(3):524-533. Wei Lin,Xu Wenguo,Yang Cang,et al.Sedimentary boundary mar-kers and geochemical indexes of shale sequence stratigraphy[J].Oil & Gas Geology,2017,38(3):524-533.
[11] Calvert S E,Bustin R M,Ingall E D.Influence of water column ano-xia and sediment supply on the burial and preservation of organic carbon in marine shales[J].Geochimica et Cosmochimica Acta,1996,60(9):1577-1593.
[12] Tyson R V.The ‘productivity versus preservation’ controversy:cause,flaws,and resolution,in Harris,N.B.,ed.,The Deposition of Orga-nic-Carbon-Rich Sediments:Models,Mechanisms,and Consequences[J]:SEPM,Special Publication 2005,82,17-33.
[13] Sageman,Bradley B.A tale of shales:the relative roles of production,decomposition,and dilution in the accumulation of organic-rich strata,Middle-Upper Devonian,Appalachian basin[J].Chemical Geology 1951(2003):229-273.
[14] Rimmer,Susan M.Multiple controls on the preservation of organic matter in Devonian-Mississippian marine black shales:geochemical and petrographic evidence[J].Palaeogeography,Palaeoclimatology,Palaeoecology,2004,215(1):125-154.
[15] Murphy,Adam E,Bradley B et al.Eutrophication by decoupling of the marine biogeochemical cycles of C,N,and P:a mechanism for the Late Devonian mass extinction[J].Geology,2000,28(5):427-430.
[16] Murphy,Adam E.Black shale deposition and faunal overturn in the Devonian Appalachian Basin:Clastic starvation,seasonal water-column mixing,and efficient biolimiting nutrient recycling[J].Paleoceanography,2000,15(3):280-291.
[17] Macquaker,Joe HS,Margaret A,et al.Algal blooms and ‘marine snow’:mechanisms that enhance preservation of organic carbon in ancient fine-grained sediments[J].Journal of Sedimentary Research,2010,80(11):934-942.
[18] Powell,Wayne G,Paul A.et al.Geochemical evidence for oxygenated bottom waters during deposition of fossiliferous strata of the Burgess Shale Formation[J].Palaeogeography,Palaeoclimatology,Palaeoeco-logy,2003,201(3):249-268.
[19] 李浩,陆建林,左宗鑫,等.长岭断陷南部断陷层湖相优质烃源岩发育控制因素[J].石油与天然气地质,2015,36(2):209-218. Li Hao,Lu Jianlin,Zuo Zongxin,et al.Controlling factors of high-quality lacustrine hydrocarbon source rocks in southern Changling Depression[J].Oil & Gas Geology,2015,36(2):209-218.
[20] 王鹏万,张磊,李昌,等.黑色页岩氧化还原条件与有机质富集机制-以昭通页岩气示范区A井五峰组-龙马溪组下段为例[J].石油与天然气地质,2017,38(5):933-943. Wang Pengwan,Zhang Lei,Li Chang,et al.Redox conditions and organic enrichment mechanisms of black shale:A case from the Wufeng-lower Longmaxi Formations in Well A in Zhaotong shale gas demonstration area[J].Oil & Gas Geology,2017,38(5):933-943.
[21] 唐文斌,徐胜林,陈洪德,等.吐哈盆地台北凹陷中部地区喀拉扎组一段震积岩的发现及其地质意义[J].石油与天然气地质,2017,38(2):345-354. Tang Wenbin,Xu Shenglin,Chen Hongde,et al.Discovery of seismites in the first member of the Kelaza Formation in central Taibei Sag of Tuha Basin and its geological significance[J].Oil & Gas Geology,2017,38(2):345-354.
[22] Pedersen T F,Calvert S E.Anoxia vs.Productivity:What controls the formation of organic-carbon-rich sediments and sedimentary rocks?[J].AAPG Bulletin,1990,74(4):454-466.
[23] Demaison G J,Moore G T,Anoxic environments and oil source bed genesis[J].AAPG,1980,64(8):1179-1209.
[24] 刘群,袁选俊,林森虎,等.鄂尔多斯盆地延长组湖相黏土岩分类和沉积环境探讨[J].沉积学报,2014,32(6):1016-1025. Liu Qun,Yuan Xuanjun,Lin Senhu et al.The classification of lacustrine mudrock and research on its depositional environment[J].Acta Sedimentologica Sinica,2014,32(6):1016-1025.
[25] 杨华,田景春,王峰.鄂尔多斯盆地三叠纪延长组沉积期湖盆边界与底形及事件沉积研究[M].北京:地质出版社,2009:4-65. Yang Hua,Tian Jingchun,Wang Feng.Lake boundary bottom feature,and accidental sendimentology of Yanchang Formation,Triassic system in Ordos Basin[M].Beijing:Geological Publishing House,2009:4-65.
[26] 邓秀芹,蔺眆哓,刘显阳等.鄂尔多斯盆地三叠系延长组沉积演化及其与早印支运动关系的探讨[J].古地理学报,2008,10(2):159-166. Deng Xiuqin,Lin Fangxiao,Liu Xianyang,et al.Discussion on relationship between sedimentary evolution of the Triassic Yanchang Formation and the Early Indosinian Movement in Ordos Basin[J].Journal of Palaeogeography,2008,10(2):159-166.
[27] 袁选俊,林森虎,刘群,等.湖盆细粒沉积特征与富有机质页岩分布模式-以鄂尔多斯盆地延长组长7油层组为[J].石油勘探与开发,2015,42(1):34-42 Yuan Xuanjun,Lin Senhu,Liu Qun,et al.Lacustrine fine-grained sedimentary features and organic-rich shale distribution pattern:A case study of Chang 7 member of Triassic Yanchang Formation in Ordos Basin,NW china[J]Petroleum Exploration and Development,2015,42(1):34-42.
[28] 张文正,杨华,杨奕华,等.鄂尔多斯盆地长7优质烃源岩岩石学、元素地球化学特征及发育环境.[J].地质化学,2008,37(1):59-64. Zhang Wenzheng,Yang Hua,Yang Yihua,et al.Petrology and element geochemistry and development environment of Yanchang Formation Chang-7 high quality source rocks in Ordos Basin[J].Geochimica,2008,37(1):59-64.
[29] Wignall,Paul B.Black shales[M].USA:Oxford University Press,1994:30.
[30] Rimmer,Susan M.Geochemical paleoredox indicators in Devonian-Mississippian black shales,central Appalachian Basin(USA)[J].Chemical Geology,2004,206(3):373-39.