ORGANO-CLAY COMPLEXES IN SOURCE ROCKS——A NATURAL MATERIAL FOR HYDROCARBON GENERATION
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摘要: 传统观点认为从烃源岩中分离出的干酪根是油气生成的母质,但它的处理方式破坏了有机质与矿物的原始赋存状态。为此,选取济阳坳陷埋深280~3 900 m烃源岩,提取<2 μm的有机黏粒复合体,研究其结构和生烃特征。有机黏粒复合体主要由蒙皂石和伊利石组成,TOC为2.62%~9.78%,经H2O2处理后TOC仍高达1.23%~4.63%,表明烃源岩中有机质主要富集在有机黏粒复合体中。有机黏粒复合体加热到250℃时,在XRD曲线上的衍射峰(d001)在1.3~1.4 nm;加热至550℃时,衍射峰(d001)才移至1.0 nm处;并且在DTA曲线上350℃附近的放热峰极其稳定,这些特征表明有机质进入到黏土矿物层间域。在PY-GC (热解-色谱)曲线上,烃源岩和有机黏粒复合体都在250~550℃释放C20-C30的有机组分,并在450℃释放量达到峰值。由此可见,烃源岩中的有机黏粒复合体,是烃源岩中有机质富集的主体,具有较好的稳定性,并释放出与原油特征相似的有机组分,表明它是具有巨大潜力的天然的生烃母质。Abstract: Traditionally, it is believed that kerogen, a organic matter insoluble in organic solvents separated chemically from source rock, is a material for hydrocarbon generation[1].The procedure to treat samples as such, however, may destroy the original occurrence and relationship between organic matter and clay in source rocks. We extracted an organo-clay complex (<2μm) from the crushed source rocks in the depth of 280~3 500 m, in the Jiyang sag, East China. The complex is mainly composed of layered illite-smectite (I-S) and illite with a value of TOC up to 2.62%~9.78%. After treatment with H2O2, TOC remains as high as 1.23%~4.63%, suggesting that it is the components in which organic matters are enriched. The diffraction peak (d001) of the complex is 1.3~1.4nm at 250℃, and moves to 1.0 nm at 550℃ in XRD curves, and the exothermic peaks of the complex is extraordinary stable at 350℃ in DTA curves.; The result is consistent in both the XRD and DTA observations. It indicates that organic matter can enter the interlayer space of clay minerals. With PY-GC analysis, the organic matter of C5 and C25 is released from the complex in a temperature range of 250~650℃, and reaches a peak at about 450℃. Our findings reveal that organic matter can enter interlayer of clay minerals forming a kind of natural and highly stable organo-clay complex, and the composition of the organic matter in the complex is similar to the crude oil. As a kind of natural material, the organo-clay complex plays an important role in hydrocarbon generation in source rocks.
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[1] Tissot B P,Welte D H. Ptroleum Formation and Occurrence(second edition)[M].New York:Springer-Verlag,1984.
[2] Weaver C E. Possible uses of clay minerals in research for oil[J]. AAPG Bull., 1960,44(9):1505-1578.
[3] Hunt J M. Petroleum Geochemistry and Geology(second edition)[M]. New York:W H Freeman and company,1996.
[4] Seewald J S.Organic-inorganic interactions in petroleum-producing sedimentary basins[J]. Nature, 2003, 426(20):327-333.
[5] Keil R G,Hedges J I.Sorption of organic matter to mineral surfaces and the preservation of organic matter in coastal marine sediments[J]. Chemical Geology, 1993,107:385-388.
[6] Bergamaschi B A, Tsamakis E, Keil R G, et al. The effect of grain size and surface area on organic matter, lignin and carbohydrate concentration, and molecular compositions in Peru Margin sediments[J]. Geochimica et Cosmochimica Acta, 1997, 61:1247-1260.
[7] 熊毅.土壤胶体(第一册)[M].北京:科学出版社,1983.[XIONG Yi.Soil Colloid (first vol)[M]. Beijing:Scienc Press, 1983.] [8] 王行信,周书欣.有机黏土化学在油气生成研究中的意义[J].地质地球化学,1991,19(5):3-8. [WANG Xingxin,ZHOU Shuxin. A research significance for organo-caly chemistry in Petroleum formation[J]. Geology-Geochemistry, 1991,19(5):3-8.]
[9] Kennedy M J, Pevear D R, Hill R H. Mineral surface control of organic carbon in black shale[J]. Science, 2002, 295:657-660.
[10] 蔡进功.泥质沉积物和泥岩中有机黏土复合体[M]. 北京:科学出版社,2004.[CAI Jingong. Organo-clay Complexes in Muddy Sediment and Muddy Rock[M]. Beijing:Science Press, 2004. [11] Weiler R R,Mills A A. Surface properties and pore structure of marine sediments[J]. Deep Sea Research, 1965,12:511-529.
[12] Suess E R. Interaction of organic compounds with calcium carbonate-Ⅱ[J]. Geochim et Cosmochim. Acta, 1973, 37:2435-2447.
[13] Mayer L M.Surface area control of organic carbon accumulation in continental shelf sediments[J]. Geochimica et Cosmochimica Acta, 1994,58:1271-1284.
[14] Mayer L M.Extent of coverage of mineral surfaces by organic matter in marine sediments[J]. Geochimica et Cosmochimica Acta, 1999.63:207-215.
[15] Keil R G., Montlucon D B, Prahl F G, et al. Sorptive preservation of labile organic matter in marine sediments[J]. Nature, 1994c, 370:549-552.
[16] Hedges J I,Keil R G.Sedimentary organic matter preservation:An assessment and speculative synthesis[J]. Marine Chemistry,1995,49:81-115.
[17] Carter M R, Angers D A, Gregorich E G, et al. Characterizing organic matter retention for surface soils in eastern Canada using density and particle size fractions[J]. Can. J. Soil Sci., 2003,83(1):11-23.
[18] Dexter A R, Richard G, Arrouays D, et al. Complexed organic matter controls soil physical properties[J]. Geoderma, 2008,(8):1-8.
[19] Durand B. Kerogen-Insoluble Organic Matter from Sedimentary Rocks[M]. Paris:Editions Technip,1980.
[20] 傅家谟,秦匡宗.干酪根地球化学[M].广州:广东科技出版社,1995.[FU Jiamo,QIN Kuangzhong. Geochemical Characteristics of Kerogen[M]. Guangzhou:Guangdong science and Technology Press,1995.] [21] 苗建宇,祝总祺, 刘文荣,等. 泥质岩有机质的赋存状态及其对泥岩封盖能力的影响[J].沉积学报,1999,7(3):1-5. [MIAO Jianyu, ZHU Zongqi, LIU Wenrong,et al. Occurrence of organic matter and its effect on sealing ability of argillaceous rock[J]. Acta Sedimentologica Sinica, 1999,7(3):1-5.]
[22] 张林晔,孔祥星,张春荣,等.济阳坳陷下第三系优质烃源岩的发育及其意义[J].地球化学,2003.32(1):35-42. [ZHANG Linye,KONG Xiangxing,ZHANG Chunrong. High quality oil prone source rocks in Jiyang Depression[J].Geochimica,2003.32(1):35-42.]
[23] Cai Jingong, Bao Yujin, Yang Shouye, et al, Research on preservation and enrichment mechanisms of organic matter in muddy sediment and mudstone[J]. Science in China (Series D),2007, 50(5):765-77.
[24] Williama L B, Canfield B, Voglesonger K M,et al. Organic molecules formed in a ‘primordial womb’[J]. Geology, 2005,33(11):913-916.
[25] 格里姆R E著,许冀泉译. 黏土矿物学[M]. 北京:地质出版社,1960:83-103.[Grim R E.(translated by XU Jiquan). Clay Minerals[M]. Beijing:Geological Publishing House, 1960:83 -103.]
[26] Armstrong D E, Chesters G. Properties of protein-bentonite complexes as influenced by equilibration conditions[J]. Soil Sci., 1964, 98:39-52.
[27] Perez Rodriguez J L, Weiss A, Lagaly G. A natural clay organic complex from Andalusian black earth[J]. Clays Clay Minerals, 1977,25:243-251.
[28] Lagaly G.Characterization of clays by organic compounds[J]. Clay Minerals, 1981,16:1-21.
[29] Zhu Jianxi, He Hongping, Guo Jiugao, et al. Arrangement models of alkylammonium cations in the interlayer of HDTMA+ pillared montmorillonites[J]. Chinese Science Bulletin, 2003,48(4):368-372.
[30] Carrado K A. Synthetic organo-and polymer-clays:preparation characterization and materials applications[J]. Appl. Clay Sci., 2000,17:1-23.
[31] Theng B K. Formation and Properties of Clay-Polymer Complexes[M]. Amsterdam:Elsevies, 1979.
[32] Yariv S,Cross H. Organic-clay Complexes and Interaction[M]. New Nork:Marcel Dekker, 2002:39-174.
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