西藏中仓盆地丁青湖组烃源岩有机地球化学特征
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摘要
探讨西藏中仓盆地古近系丁青湖组烃源岩有机地球化学特征,为油气勘探提供参考。通过对丁青湖组烃源岩的沉积特征、有机质丰度、有机质类型、有机质成熟度和生物标志化合物等方面的研究,表明丁青湖组主要为扇三角洲沉积体系和湖泊沉积体系,发育于湖泊体系中的薄层泥岩、泥灰岩为潜在的烃源岩。丁青湖组灰岩有机碳质量分数平均为0.0448%,泥岩有机碳质量分数平均为0.048%;姥鲛烷与植烷的比值(Pr/Ph)为0.45～1.8,γ蜡烷指数平均为0.32,C_(27)、C_(28)、C_(29)甾烷含量呈"V"字形分布,升藿烷指数为0.01～0.08,有机质总体上处于未成熟—低成熟演化阶段。中仓盆地丁青湖组烃源岩生油潜力较差,有机质主要来源于陆生高等植物与水生生物,沉积时主要为缺氧的湖泊相还原环境,水体较为稳定,具有一定的盐度。
The organic geochemical characteristics of the Palaeogene Dingqinghu Formation source rocks in the Zhongcang Basin are discussed so as to provide reference for subsequent oil and gas exploration. Study of the sedimentary characteristics, organic matter abundance, organic matter type, organic matter maturity and biomarker compounds of the Dingqinghu Formation source rocks shows that the sedimentary systems of the Dingqinghu Formation in the Zhongcang Basin are mainly fan delta and lake sedimentary systems. Thin bedded mudstones and marl rocks developed in the lake system are potential source rocks. The average mass fraction of organic carbon for limestone is 0.0448% and average value of organic carbon mass fraction for mudstone is 0.048%. The ratio of pristane to phytane(Pr/Ph) ranges from 0.45 to 1.8 and the average value of γ-cerane index are 0.32. The content of C_(27), C_(28) and C_(29) sterane is "V"-shaped, and the homohopane index is 0.01～0.08. It shows that the organic matter is generally in the immature-low-mature evolution stage. According to the comprehensive analysis, the source rocks of the Zhongcang Basin have poor oil-producing potential because the organic matter is mainly derived from terrestrial higher plants and aquatic organisms in a sedimentary environment of anoxic lake phase reduction with stable water body and with certain salinity.
The organic geochemical characteristics of the Palaeogene Dingqinghu Formation source rocks in the Zhongcang Basin are discussed so as to provide reference for subsequent oil and gas exploration. Study of the sedimentary characteristics, organic matter abundance, organic matter type, organic matter maturity and biomarker compounds of the Dingqinghu Formation source rocks shows that the sedimentary systems of the Dingqinghu Formation in the Zhongcang Basin are mainly fan delta and lake sedimentary systems. Thin bedded mudstones and marl rocks developed in the lake system are potential source rocks. The average mass fraction of organic carbon for limestone is 0.0448% and average value of organic carbon mass fraction for mudstone is 0.048%. The ratio of pristane to phytane(Pr/Ph) ranges from 0.45 to 1.8 and the average value of γ-cerane index are 0.32. The content of C_(27), C_(28) and C_(29) sterane is "V"-shaped, and the homohopane index is 0.01～0.08. It shows that the organic matter is generally in the immature-low-mature evolution stage. According to the comprehensive analysis, the source rocks of the Zhongcang Basin have poor oil-producing potential because the organic matter is mainly derived from terrestrial higher plants and aquatic organisms in a sedimentary environment of anoxic lake phase reduction with stable water body and with certain salinity.
引文
[1] 王剑.青藏高原重点沉积盆地油气资源潜力分析[M].北京:地质出版社,2004.Wang J. Analysis of Potential Oil and Gas Resources in Key Sedimentary Basins of Qinghai Tibet Plateau [M]. Beijing: Geological Publishing House, 2004. (in Chinese)
[2] 王剑,谭富文,李亚林,等.青藏高原重点沉积盆地沉积特征及其油气资源潜力分析[C]//全国沉积学大会论文集.北京:地质出版社,2005:321-323. (in Chinese)Wang J, Tan F W, Li Y L, et al. Sedimentary characteristics of key sedimentary basins in the Qinghai-Tibet Plateau and their potential for oil and gas resources [C]//National Sedimentology Conference. Beijing: Geological Publishing House, 2005. (in Chinese)
[3] 王成善,李亚林,李永铁.青藏高原油气资源远景评价问题[J].石油学报,2006,27(4):1-7.Wang C S, Li Y L, Li Y T. Discussion on evaluation of oil and gas resources in Qinghai-Tibet Plateau[J]. Acta Petrolei Sinica, 2006, 27(4): 1-7. (in Chinese)
[4] 丘东洲.西藏——我国西部21世纪新的油气资源接替区[J].新疆石油地质,2004,25(3):233-239. Qiu D Z. Tibet—A new take-over region for petroleum resources of 21st Century in West China[J]. Xinjiang Petroleum Geology, 2004, 25(3): 233-239. (in Chinese)
[5] 顾忆,邵志兵,叶德燎.西藏伦坡拉盆地烃源岩特征及资源条件[J].石油实验地质,1999,21(4):340-345.Gu Y, Shao Z B, Ye D L. Characteristics of source rocks and resource prospect in the Lunpola Basin, Tibet[J]. Petroleum Geology and Experiment, 1999, 21(4): 340-345. (in Chinese)
[6] 李亚林,王成善,朱利东,等.西藏尼玛盆地油页岩的发现及其地质意义[J].地质通报,2010,29(12):1872-1874.Li Y L, Wang C S, Zhu L D, et al. Discovery of oil shale in the Nima Basin, Tibet, China and its significance[J]. Geological Bulletin of China, 2010, 29(12):1872-1874. (in Chinese)
[7] 曾菁,李亚林,王立成.西藏洞错盆地古近系丁青湖组烃源岩评价[J].新疆石油地质,2011,32(1):11-13.Zeng J, Li Y L, Wang L C. Evaluation of Paleogene Dingqinghu source rocks in Dongcuo Basin, Tibet[J]. Xinjiang Petroleum Geology, 2011, 32(1): 11-13. (in Chinese)
[8] 胡承飞,史建南,普玉浩,等.西藏洞错盆地丁青湖组储层岩石学特征及储集类型[J].石化技术,2017,24(5):120-120. Hu C F, Shi J N, Pu Y H, et al. Lithology characteristics and reservoir types of Dingqinghu reservoir formations in Tibet Dongcuo basin[J]. Petrochemical Industry Technology, 2017, 24(5): 120-120. (in Chinese)
[9] 秦建中,刘宝泉,国建英,等.关于碳酸盐烃源岩的评价标准[J].石油实验地质,2004,26(3):281-286. Qin J Z, Liu B Q, Guo J Y, et al. Discussion on the evaluation standards of carbonate source rocks[J]. Petroleum Geology and Experiment, 2004, 26(3): 281-286. (in Chinese)
[10] 张君峰,王东良,秦建中,等.青藏高原地面露头样品风化校正研究[J].石油实验地质,2001,23(3):297-300.Zhang J F, Wang D L, Qin J Z, et al. Study on the weathering correction of surface outcrop samples from the Qinghai-Tibet Plateau[J]. Petroleum Geology and Experiment, 2001, 23(3): 297-300. (in Chinese)
[11] 孙瑕,伊海生,林金辉,等.青藏高原北部新生代陆相盆地石油地质条件及勘探前景[J].沉积与特提斯地质, 2008,28(4):7-13.Sun X, Y H S, Lin J H, et al. Petroleum geology and exploration prospects in the Cenozoic continental basins in the northern part of the Qinghai-Xizang Plateau[J]. Sedimentary Geology and Tethyan Geology, 2008, 28(4): 7-13. (in Chinese)
[12] 李亚林.羌塘盆地托纳木地区石油地质特征与资源潜力[M].北京:地质出版社, 2011.Li Y L. Petroleum Geological Characteristics and Resource Potential in Tonamu Area, Qiangtang Basin [M]. Beijing: Geological Publishing House, 2011. (in Chinese)
[13] Didyk B M, Simoneit B R T, Brassell S C, et al. Organic geochemical indicators of palaeoenvironmental conditions of sedimentation[J]. Nature, 1978, 272(5650): 216-222.
[14] Shanmugam G. Significance of coniferous rain forests and related organic matter in generating commercial quantities of oil, Gippsland Basin, Australia[J]. Aapg Bulletin, 1985, 69(8): 1241-1254.
[15] Peters K E, Moldowan J M. Effects of source, thermal maturity, and biodegradation on the distribution and isomerization of homohopanes in petroleum [J]. Organic Geochemistry, 1991, 17(1): 47-61.
[16] Pancost R D, Freeman K H, Patzkowsky M E, et al. Molecular indicators of redox and marine photoautotroph composition in the late Middle Ordovician of Iowa, U.S.A[J]. Organic Geochemistry, 1998, 29(5/7): 1649-1662.
[17] 陈珊,刘博,刘旭锋,等.西藏伦坡拉盆地古近系页岩油资源潜力初探[J].地球学报,2017,38(5):839-846.Chen S, Liu B, Liu X F, et al. A preliminary study of the Paleogene shale oil potential in Lunpola Basin, Tibet[J]. Acta Geoscientica Sinica, 2017, 38(5): 839-846. (in Chinese)
[18] 陈义才,沈忠民,罗小平.石油与天然气有机地球化学[M].北京:科学出版社,2007.Chen Y C, Shen Z M, Luo X P. Petroleum and Natural Gas Organic Geochemistry [M]. Beijing: Science Press, 2007. (in Chinese)
[19] 傅家谟,盛国英,许家友,等.应用生物标志化合物参数判识古沉积环境[J].地球化学,1991,20(1):1-12.Fu J M, Sheng G Y, Xu J Y, et al. Applicat1on of biomarker compounds in assessment of paleoenvironments of Chinese terrestrial sediments[J]. Geochimica, 1991, 20(1): 1-12. (in Chinese)
[20] 陈庆,史建南,朱利东,等.西藏中仓盆地古近系丁青湖组生烃潜力与沉积有机相分析[J].东北石油大学学报,2017,41(4):71-78.Chen Q, Shi J N, Zhu L D, et al. Analysis of hydrocarbon generation potential and sedimentary organic facies of the Paleogene Dingqinghu Formation in Zhongcang Basin, Tibet [J]. Journal of Northeast Petroleum University, 2017, 41(4): 71-78. (in Chinese)
[21] 杜佰伟,谢尚克,董宇,等.伦坡拉盆地渐新统丁青湖组油页岩特征及其地质意义[J].吉林大学学报(地球科学版),2016,46(3):671-680.Du B W, Xie S K, Dong Y, et al. Characteristics of oil shale of Oligocene Dingqinghu Formation and its geological significance, Lunpola Basin[J]. Journal of Jilin University (Earth Science Edition), 2016, 46(3): 671-680. (in Chinese)
[2] 王剑,谭富文,李亚林,等.青藏高原重点沉积盆地沉积特征及其油气资源潜力分析[C]//全国沉积学大会论文集.北京:地质出版社,2005:321-323. (in Chinese)Wang J, Tan F W, Li Y L, et al. Sedimentary characteristics of key sedimentary basins in the Qinghai-Tibet Plateau and their potential for oil and gas resources [C]//National Sedimentology Conference. Beijing: Geological Publishing House, 2005. (in Chinese)
[3] 王成善,李亚林,李永铁.青藏高原油气资源远景评价问题[J].石油学报,2006,27(4):1-7.Wang C S, Li Y L, Li Y T. Discussion on evaluation of oil and gas resources in Qinghai-Tibet Plateau[J]. Acta Petrolei Sinica, 2006, 27(4): 1-7. (in Chinese)
[4] 丘东洲.西藏——我国西部21世纪新的油气资源接替区[J].新疆石油地质,2004,25(3):233-239. Qiu D Z. Tibet—A new take-over region for petroleum resources of 21st Century in West China[J]. Xinjiang Petroleum Geology, 2004, 25(3): 233-239. (in Chinese)
[5] 顾忆,邵志兵,叶德燎.西藏伦坡拉盆地烃源岩特征及资源条件[J].石油实验地质,1999,21(4):340-345.Gu Y, Shao Z B, Ye D L. Characteristics of source rocks and resource prospect in the Lunpola Basin, Tibet[J]. Petroleum Geology and Experiment, 1999, 21(4): 340-345. (in Chinese)
[6] 李亚林,王成善,朱利东,等.西藏尼玛盆地油页岩的发现及其地质意义[J].地质通报,2010,29(12):1872-1874.Li Y L, Wang C S, Zhu L D, et al. Discovery of oil shale in the Nima Basin, Tibet, China and its significance[J]. Geological Bulletin of China, 2010, 29(12):1872-1874. (in Chinese)
[7] 曾菁,李亚林,王立成.西藏洞错盆地古近系丁青湖组烃源岩评价[J].新疆石油地质,2011,32(1):11-13.Zeng J, Li Y L, Wang L C. Evaluation of Paleogene Dingqinghu source rocks in Dongcuo Basin, Tibet[J]. Xinjiang Petroleum Geology, 2011, 32(1): 11-13. (in Chinese)
[8] 胡承飞,史建南,普玉浩,等.西藏洞错盆地丁青湖组储层岩石学特征及储集类型[J].石化技术,2017,24(5):120-120. Hu C F, Shi J N, Pu Y H, et al. Lithology characteristics and reservoir types of Dingqinghu reservoir formations in Tibet Dongcuo basin[J]. Petrochemical Industry Technology, 2017, 24(5): 120-120. (in Chinese)
[9] 秦建中,刘宝泉,国建英,等.关于碳酸盐烃源岩的评价标准[J].石油实验地质,2004,26(3):281-286. Qin J Z, Liu B Q, Guo J Y, et al. Discussion on the evaluation standards of carbonate source rocks[J]. Petroleum Geology and Experiment, 2004, 26(3): 281-286. (in Chinese)
[10] 张君峰,王东良,秦建中,等.青藏高原地面露头样品风化校正研究[J].石油实验地质,2001,23(3):297-300.Zhang J F, Wang D L, Qin J Z, et al. Study on the weathering correction of surface outcrop samples from the Qinghai-Tibet Plateau[J]. Petroleum Geology and Experiment, 2001, 23(3): 297-300. (in Chinese)
[11] 孙瑕,伊海生,林金辉,等.青藏高原北部新生代陆相盆地石油地质条件及勘探前景[J].沉积与特提斯地质, 2008,28(4):7-13.Sun X, Y H S, Lin J H, et al. Petroleum geology and exploration prospects in the Cenozoic continental basins in the northern part of the Qinghai-Xizang Plateau[J]. Sedimentary Geology and Tethyan Geology, 2008, 28(4): 7-13. (in Chinese)
[12] 李亚林.羌塘盆地托纳木地区石油地质特征与资源潜力[M].北京:地质出版社, 2011.Li Y L. Petroleum Geological Characteristics and Resource Potential in Tonamu Area, Qiangtang Basin [M]. Beijing: Geological Publishing House, 2011. (in Chinese)
[13] Didyk B M, Simoneit B R T, Brassell S C, et al. Organic geochemical indicators of palaeoenvironmental conditions of sedimentation[J]. Nature, 1978, 272(5650): 216-222.
[14] Shanmugam G. Significance of coniferous rain forests and related organic matter in generating commercial quantities of oil, Gippsland Basin, Australia[J]. Aapg Bulletin, 1985, 69(8): 1241-1254.
[15] Peters K E, Moldowan J M. Effects of source, thermal maturity, and biodegradation on the distribution and isomerization of homohopanes in petroleum [J]. Organic Geochemistry, 1991, 17(1): 47-61.
[16] Pancost R D, Freeman K H, Patzkowsky M E, et al. Molecular indicators of redox and marine photoautotroph composition in the late Middle Ordovician of Iowa, U.S.A[J]. Organic Geochemistry, 1998, 29(5/7): 1649-1662.
[17] 陈珊,刘博,刘旭锋,等.西藏伦坡拉盆地古近系页岩油资源潜力初探[J].地球学报,2017,38(5):839-846.Chen S, Liu B, Liu X F, et al. A preliminary study of the Paleogene shale oil potential in Lunpola Basin, Tibet[J]. Acta Geoscientica Sinica, 2017, 38(5): 839-846. (in Chinese)
[18] 陈义才,沈忠民,罗小平.石油与天然气有机地球化学[M].北京:科学出版社,2007.Chen Y C, Shen Z M, Luo X P. Petroleum and Natural Gas Organic Geochemistry [M]. Beijing: Science Press, 2007. (in Chinese)
[19] 傅家谟,盛国英,许家友,等.应用生物标志化合物参数判识古沉积环境[J].地球化学,1991,20(1):1-12.Fu J M, Sheng G Y, Xu J Y, et al. Applicat1on of biomarker compounds in assessment of paleoenvironments of Chinese terrestrial sediments[J]. Geochimica, 1991, 20(1): 1-12. (in Chinese)
[20] 陈庆,史建南,朱利东,等.西藏中仓盆地古近系丁青湖组生烃潜力与沉积有机相分析[J].东北石油大学学报,2017,41(4):71-78.Chen Q, Shi J N, Zhu L D, et al. Analysis of hydrocarbon generation potential and sedimentary organic facies of the Paleogene Dingqinghu Formation in Zhongcang Basin, Tibet [J]. Journal of Northeast Petroleum University, 2017, 41(4): 71-78. (in Chinese)
[21] 杜佰伟,谢尚克,董宇,等.伦坡拉盆地渐新统丁青湖组油页岩特征及其地质意义[J].吉林大学学报(地球科学版),2016,46(3):671-680.Du B W, Xie S K, Dong Y, et al. Characteristics of oil shale of Oligocene Dingqinghu Formation and its geological significance, Lunpola Basin[J]. Journal of Jilin University (Earth Science Edition), 2016, 46(3): 671-680. (in Chinese)