珠江口盆地不同类型原油地球化学特征
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摘要
为明确白云凹陷目前发现原油的成因及来源,系统分析取自珠江口盆地不同类型原油中各类生物标志物的分布与组成特征,发现番禺低隆起北部构造及番禺4洼的原油具有姥植比低(<2.0),指示陆源有机质输入的奥利烷含量中等,基本缺乏达玛树脂贡献的双杜松烷,各类重排构型甾藿含量较低,而指示沟鞭藻贡献的C_(30)4-甲基甾烷异常丰富的特点。C_(30)4-甲基甾烷与C_(29)规则甾烷的比值>2.1,且其三环萜烷系列C_(19-26)呈现以C_(21)为主峰的正态分布,指示其原始生烃母质以藻类为主,表明这类原油与文昌组湖相烃源岩具有较好的可比性;而番禺低隆起南部构造及白云凹陷的凝析油具有姥植比高(>4.0),明显富含奥利烷和双杜松烷,各类重排构型甾藿烷含量较高,缺乏C_(30)4-甲基甾烷的特点,且其三环萜烷C_(19-26)呈现阶梯状依次降低的特点,表明陆源有机质是其主要原始生烃母质,这符合白云凹陷发育恩平组煤系烃源岩的石油地质背景。
To figure out the origin and sources of crude oils from Baiyun sag of the Pearl River Mouth Basin,the authors analyzed the distributions and compositions of various biomarkers in two kinds of crude oils from different tectonic units in the Pearl River Mouth Basin systematically.It is found that the Pr/Ph ratios of the crude oils from the north structures of the Panyu low uplift and panyu 4 sub-sag are relatively low(< 2.0),which indicates that the terrigenous organic matter input is moderate,and the bicadinanes derived from dammar resin are almost absent,the contents of rearranged steranes and hopanes are low.However,C_(30)4-methyl steranes related to dinoflagellates are abnormally abundant,and the ratio of C_(30)4-methyl steranes and C_(29) regular sterane is more than 2.1,and the C_(19-26) tricyclic terpanes show a normal distribution while the dominant peak is C_(21),suggesting that algae has made an important contribution to original hydrocarbon parent material,which is consistent with that of lacustrine source rocks of the Wenchang Formation.The Pr/Ph ratios of the condensates from the south structures of the Panyu low uplift and Baiyun sag are more than 4.0,with abundant oleanane and bicadinanes,the contents of rearranged steranes and hopanes are relatively high,lacking C_(30)4-methyl steranes.While tricyclic terpane C_(19-26)pres-ents the characteristics of the trapezium in turn reduce,indicating that terrigenous organic matter is their original parent material,which accords with the petroleum geology background of the development of coal-containing source rocks of the Enping Formation in the Baiyun sag.
To figure out the origin and sources of crude oils from Baiyun sag of the Pearl River Mouth Basin,the authors analyzed the distributions and compositions of various biomarkers in two kinds of crude oils from different tectonic units in the Pearl River Mouth Basin systematically.It is found that the Pr/Ph ratios of the crude oils from the north structures of the Panyu low uplift and panyu 4 sub-sag are relatively low(< 2.0),which indicates that the terrigenous organic matter input is moderate,and the bicadinanes derived from dammar resin are almost absent,the contents of rearranged steranes and hopanes are low.However,C_(30)4-methyl steranes related to dinoflagellates are abnormally abundant,and the ratio of C_(30)4-methyl steranes and C_(29) regular sterane is more than 2.1,and the C_(19-26) tricyclic terpanes show a normal distribution while the dominant peak is C_(21),suggesting that algae has made an important contribution to original hydrocarbon parent material,which is consistent with that of lacustrine source rocks of the Wenchang Formation.The Pr/Ph ratios of the condensates from the south structures of the Panyu low uplift and Baiyun sag are more than 4.0,with abundant oleanane and bicadinanes,the contents of rearranged steranes and hopanes are relatively high,lacking C_(30)4-methyl steranes.While tricyclic terpane C_(19-26)pres-ents the characteristics of the trapezium in turn reduce,indicating that terrigenous organic matter is their original parent material,which accords with the petroleum geology background of the development of coal-containing source rocks of the Enping Formation in the Baiyun sag.
引文
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[8]陈长民,黄丽芬,李昭伟.番禺4-2油藏的形成条件及勘探意义[J].中国海上油气(地质),1999,13(3):145-151.CHEN Chang-min,HUANG Li-fen,LI Zhao-wei.Accumulation conditions of PY4-2 oil pool and implication for exploration[J].China Offshore Oil and Gas(Geology),1999,13(3):145-151.
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[10]施和生,朱俊章,姜正龙,等.珠江口盆地珠Ⅰ坳陷油气资源再评价[J].中国海上油气,2009,21(1):9-14.SHI He-sheng,ZHU Jun-zhang,JIANG Zheng-long,et al.Hydrocarbon resources reassessment in Zhu I Depression,Pearl River Mouth basin[J].China Offshore Oil and Gas,2009,21(1):9-14.
[11]Alexander R,Kagi R I,Volkman J K,et al.The geochemistry of some biodegraded Australian oils[J].Australian Petroleum Exploration Association Journal,1983,23(1):53-63.
[12]Volkman J K.Biological marker compounds as indicators of the depositional environments of petroleum source rocks[C]//Fleet A J,Kelts K,Talbot M R,eds.Lacustrine petroleum source rocks.Special Publication No.40.Geological Society,London,1988:103-122.
[13]包建平,马安来,黄光辉,等.三塘湖盆地原油地球化学特征及其成因类型[J].石油勘探与开发,1999,26(4):25-29.BAO Jian-ping,MA An-lai,HUANG Guang-hui,et al.The origin and geochemical characteristics of crude oils from Santanghu Basin[J].Petroleum Exploration and Development,1999,26(4):25-29.
[14]包建平,朱翠山,倪春华.北部湾盆地不同凹陷原油生物标志物分布与组成特征[J].沉积学报,2007,25(4):646-652.BAO Jian-ping,ZHU Cui-shan,NI Chun-hua.Distribution and composition of biomarkers in crude oils from different sags of Beibuwan Basin[J].Acta Sedimentologica Sinica,2007,25(4):646-652.
[15]Moldowan J M,Fago F J,Carlson R M K,et al.Rearranged hopanes in sediments and petroleum[J].Geochimica et Cosmochimica Acta,1991,55:3333-3353.
[16]Peters K E,Moldowan J M.The biomarker guide:interpreting molecular fossils in petroleum and ancient sediments[J].Prentice Hall Inc,1993:1-347.
[17]Ourisson G,Rohmer M,Poralla K.Prokaryotic hopanoids and other polyterpenoid sterol surrogates[J].Annual Review of Microbiology,1987,41:301-333.
[18]Nytoft H P,Bojesen-Koefoed J R A,Christiansen F G,et al.Oleanane or lupane?Reappraisal of the presence of oleanane in Cretaceous-Tertiary oils and sediments[J].Organic Geochemistry,2002,33(11):1225-1240.
[19]Van Aarssen B G K,de Leeuw J W.On the identification and occurrence of oligomerized sesquiterpenoid compounds in oils and sediments of southeast Asia[C]//Abstracts of the 14th International Meeting on Organic Geochemistry,Paris,September,1989:18-22.
[20]Van Aarssen B G K,Cox H C,Hoogendoorn P,et al.A cadinane biopolymer present in fossil and extant dammar resins as source for cadinanes and dicadinanes in crude oils from South East Asia[J].Geochimica et Cosmochimica Acta,1990,54:302-303.
[21]De leeuw J M,Cox H C,Yan Grass G,et al.Limited double bond isomerisation and selective hydrogenation of sterenes during early diagenesis[J].Geochimica et Cosmochimica Acta,1989,53:903-909.
[22]Wolff G A,Lamb N A,Maxwell J R.The origin and fate of 4-methyl steroid hydrocarbons I.4-methyl steranes[J].Geochimica et Cosmochimica Acta,1986,50:335-342.
(1)包建平,朱翠山.白云凹陷烃源岩及油气地球化学特征研究(内部研究报告).武汉:长江大学与中海油(中国)有限公司深圳分公司,2010.
[2]傅宁,米立军,张功成.珠江口盆地白云凹陷烃源岩及北部油气成因[J].石油学报,2007,28(3):32-38.FU Ning,MI Li-jun,ZHANG Gong-cheng.Source rocks and origin of oil and gas in the northern Baiyun Depression of Pearl River Mouth Basin[J].Acta Petrolei Sinica,2007,28(3):32-38.
[3]朱俊章,施和生,庞雄,等.珠江口盆地番禺低隆起凝析油地球化学特征及油源分析[J].中国海上油气,2006,18(2):103-106.ZHU Jun-zhang,SHI He-sheng,PANG Xiong,et al.Geochemical characteristics and oil sources of condensates in Panyu Low Uplift,Pearl River Mouth Basin[J].China Offshore Oil and Gas,2006,18(2):103-106.
[4]陈长民.珠江口盆地东部石油地质及油气藏形成条件初探[J].中国海上油气(地质),2000,14(2):73-83.CHEN Chang-min.Petroleum geology and conditions for hydrocarbon accumulation in the eastern Pearl River Mouth Basin[J].China Offshore Oil and Gas(Geology),2000,14(2):73-83.
[5]陈长民,施和生,许仕策,等.珠江口盆地(东部)第三系油气藏形成条件[M].北京:科学出版社,2003:76-77.CHEN Chang-min,SHI He-sheng,XU Shi-ce,et al.Formation conditions of tertiary oil and gas reservoirs in the(eastern)Pearl River Mouth Basin[M].Beijing:Science Press,2003:76-77.
[6]郭伯举,谢家声,向凤典.珠江口盆地珠Ⅰ坳陷含油气系统研究[J].中国海上油气(地质),2000,14(1):1-8.GUO Bo-ju,XIE Jia-sheng,XIANG Feng-dian.The study of the petroleum system in the ZhuⅠDepression in Pearl River Mouth Basin[J].China Offshore Oil and Gas(Geology),2000,14(1):1-8.
[7]陈长民.珠江口盆地(东部)新生代油气藏形成条件及类型[J].复式油气田,1996,1(1):20-26.CHEN Chang-min.Formation conditions and types of Cenozoic era oil and gas reservoirs in the(eastern)Pearl River Mouth Basin[J].Duplex Oil and Gas Fields,1996,1(1):20-26.
[8]陈长民,黄丽芬,李昭伟.番禺4-2油藏的形成条件及勘探意义[J].中国海上油气(地质),1999,13(3):145-151.CHEN Chang-min,HUANG Li-fen,LI Zhao-wei.Accumulation conditions of PY4-2 oil pool and implication for exploration[J].China Offshore Oil and Gas(Geology),1999,13(3):145-151.
[9]刘从印,周平兵,曾驿,等.番禺4洼地区新近系油气成藏主控因素分析[J].中国海上油气,2009,21(2):91-94.LIU Cong-yin,ZHOU Ping-bing,ZENG Yi,et al.An analysis of the main controls on Neogene hydrocarbon accumulation in Panyu 4 sag[J].China Offshore Oil and Gas,2009,21(2):91-94.
[10]施和生,朱俊章,姜正龙,等.珠江口盆地珠Ⅰ坳陷油气资源再评价[J].中国海上油气,2009,21(1):9-14.SHI He-sheng,ZHU Jun-zhang,JIANG Zheng-long,et al.Hydrocarbon resources reassessment in Zhu I Depression,Pearl River Mouth basin[J].China Offshore Oil and Gas,2009,21(1):9-14.
[11]Alexander R,Kagi R I,Volkman J K,et al.The geochemistry of some biodegraded Australian oils[J].Australian Petroleum Exploration Association Journal,1983,23(1):53-63.
[12]Volkman J K.Biological marker compounds as indicators of the depositional environments of petroleum source rocks[C]//Fleet A J,Kelts K,Talbot M R,eds.Lacustrine petroleum source rocks.Special Publication No.40.Geological Society,London,1988:103-122.
[13]包建平,马安来,黄光辉,等.三塘湖盆地原油地球化学特征及其成因类型[J].石油勘探与开发,1999,26(4):25-29.BAO Jian-ping,MA An-lai,HUANG Guang-hui,et al.The origin and geochemical characteristics of crude oils from Santanghu Basin[J].Petroleum Exploration and Development,1999,26(4):25-29.
[14]包建平,朱翠山,倪春华.北部湾盆地不同凹陷原油生物标志物分布与组成特征[J].沉积学报,2007,25(4):646-652.BAO Jian-ping,ZHU Cui-shan,NI Chun-hua.Distribution and composition of biomarkers in crude oils from different sags of Beibuwan Basin[J].Acta Sedimentologica Sinica,2007,25(4):646-652.
[15]Moldowan J M,Fago F J,Carlson R M K,et al.Rearranged hopanes in sediments and petroleum[J].Geochimica et Cosmochimica Acta,1991,55:3333-3353.
[16]Peters K E,Moldowan J M.The biomarker guide:interpreting molecular fossils in petroleum and ancient sediments[J].Prentice Hall Inc,1993:1-347.
[17]Ourisson G,Rohmer M,Poralla K.Prokaryotic hopanoids and other polyterpenoid sterol surrogates[J].Annual Review of Microbiology,1987,41:301-333.
[18]Nytoft H P,Bojesen-Koefoed J R A,Christiansen F G,et al.Oleanane or lupane?Reappraisal of the presence of oleanane in Cretaceous-Tertiary oils and sediments[J].Organic Geochemistry,2002,33(11):1225-1240.
[19]Van Aarssen B G K,de Leeuw J W.On the identification and occurrence of oligomerized sesquiterpenoid compounds in oils and sediments of southeast Asia[C]//Abstracts of the 14th International Meeting on Organic Geochemistry,Paris,September,1989:18-22.
[20]Van Aarssen B G K,Cox H C,Hoogendoorn P,et al.A cadinane biopolymer present in fossil and extant dammar resins as source for cadinanes and dicadinanes in crude oils from South East Asia[J].Geochimica et Cosmochimica Acta,1990,54:302-303.
[21]De leeuw J M,Cox H C,Yan Grass G,et al.Limited double bond isomerisation and selective hydrogenation of sterenes during early diagenesis[J].Geochimica et Cosmochimica Acta,1989,53:903-909.
[22]Wolff G A,Lamb N A,Maxwell J R.The origin and fate of 4-methyl steroid hydrocarbons I.4-methyl steranes[J].Geochimica et Cosmochimica Acta,1986,50:335-342.
(1)包建平,朱翠山.白云凹陷烃源岩及油气地球化学特征研究(内部研究报告).武汉:长江大学与中海油(中国)有限公司深圳分公司,2010.