琼东南盆地古近纪成煤沉积体系类型及特征
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摘要
琼东南盆地天然气勘探开发事实证明,煤系及煤层是最重要的生烃源岩。基于琼东南盆地地震资料、钻井岩心及测井资料,在对古近系渐新统含煤沉积特征分析的基础上,建立了沉积相与地震相的对应关系,识别出琼东南盆地渐新统发育冲积扇-潮坪-潟湖组合、冲积扇-潮坪-滨海组合、冲积扇-海沼沙岭平原-滨海组合等14种沉积组合;依据取心段煤的宏观与微观物理化学性质,判断崖城组煤层形成过程中受海水影响且沉积环境还原性较强,说明煤层形成于近海沼泽环境。基于成煤特征及成煤环境分析,划分出4类成煤沉积体系,分别为扇三角洲体系、辫状河三角洲体系、潮坪-潟湖体系和障壁海岸-海沼沙岭平原体系。扇三角洲体系煤层主要发育在扇三角洲平原、废弃朵体、朵体间洼地,煤层较薄,且易发生分叉;辫状河三角洲体系煤层主要发育在辫状河三角洲平原、分流间湾和泛滥平原等地区,煤层薄且不稳定;潮坪-潟湖体系中煤层多发育在潮上坪的沼泽及潮间坪上部的潮道间湾,潮汐三角洲平原以及淤化的潟湖等地区,在多潮道地区,煤层层数多,但厚度较薄,煤层间距大;而在潮道不发育地区,含煤层数较少,但厚度较大,煤层间距较小,煤层结构复杂;障壁海岸-海沼沙岭平原体系煤层主要发育在海岸平原沼泽地区,煤层层数多、但单层厚度小和横向变化较快。
The practice for exploring natural gas in Qiongdongnan Basin proves that coal measures and coal seams are the most important hydrocarbon source rocks. Based on the characteristic analysis of coal-bearing deposits in the Oligocene Paleogene by the seismic data,drilling core and logging data in Qiongdongnan Basin,the corresponding relationships between sedimentary facies and seismic facies are established,and 14 kinds of sedimentary assemblages are identified in the Oligocene of Qiongdongnan Basin,including the alluvial fan-tidal flat-lagoon,alluvial fan-tidal flat-coast,alluvial fan-sea bog sand ridge plain-coast assemblages. According to the micro-and macro-physicochemical properties of cored coal intervals,it is made certain that the Yacheng Formation coal seam was affected by seawater during its formative process and its sedimentary environment tended to be strong in reduction,indicating that the coal seam is developed in the offshore marsh environment. In view of the characteristic and environmental analysis for coal forming,four types of coal-forming sedimentary systems were classified,namely fan delta,braided river delta,tidal flat-lagoon and barrier-coast-sea marsh sand ridge plain systems. Among them,the thin coal seam in the fan delta system,prone to bifurcation,is mainly developed in the fan delta plains,abandoned lobes,and interlobe depressions; the coal seam in the braided river delta system,featuring thinness and instability,mainly grows in the braided river delta plains,diversion bays,and floodplains. The coal seam in thetidal-lagoon system is mostly developed in the swamps of the supratidal flats and the inter-tidal-channel bays of the upper intertidal flats,the tidal delta plains and the silted lagoons,and in areas of multiple tidal channels,the coal seam layers are relatively large in number,and characterized by thinness and larger spacing,while in areas of single tidal channels,the number of coal-bearing seams,complex in structure,is relatively small,but their thickness is relatively large,and their spacing is small. At last,the coal seam in the barrier coast-sea marsh sand plain system is mainly developed in coastal plain marsh areas,characterized by multiple layers and faster change in lateral,but thinness for each layer.
The practice for exploring natural gas in Qiongdongnan Basin proves that coal measures and coal seams are the most important hydrocarbon source rocks. Based on the characteristic analysis of coal-bearing deposits in the Oligocene Paleogene by the seismic data,drilling core and logging data in Qiongdongnan Basin,the corresponding relationships between sedimentary facies and seismic facies are established,and 14 kinds of sedimentary assemblages are identified in the Oligocene of Qiongdongnan Basin,including the alluvial fan-tidal flat-lagoon,alluvial fan-tidal flat-coast,alluvial fan-sea bog sand ridge plain-coast assemblages. According to the micro-and macro-physicochemical properties of cored coal intervals,it is made certain that the Yacheng Formation coal seam was affected by seawater during its formative process and its sedimentary environment tended to be strong in reduction,indicating that the coal seam is developed in the offshore marsh environment. In view of the characteristic and environmental analysis for coal forming,four types of coal-forming sedimentary systems were classified,namely fan delta,braided river delta,tidal flat-lagoon and barrier-coast-sea marsh sand ridge plain systems. Among them,the thin coal seam in the fan delta system,prone to bifurcation,is mainly developed in the fan delta plains,abandoned lobes,and interlobe depressions; the coal seam in the braided river delta system,featuring thinness and instability,mainly grows in the braided river delta plains,diversion bays,and floodplains. The coal seam in thetidal-lagoon system is mostly developed in the swamps of the supratidal flats and the inter-tidal-channel bays of the upper intertidal flats,the tidal delta plains and the silted lagoons,and in areas of multiple tidal channels,the coal seam layers are relatively large in number,and characterized by thinness and larger spacing,while in areas of single tidal channels,the number of coal-bearing seams,complex in structure,is relatively small,but their thickness is relatively large,and their spacing is small. At last,the coal seam in the barrier coast-sea marsh sand plain system is mainly developed in coastal plain marsh areas,characterized by multiple layers and faster change in lateral,but thinness for each layer.
引文
[1]张亚雄,朱筱敏,张功成,等.琼东南盆地古近系陵水组层序地层特征[J].油气地质与采收率,2013,20(5):33-37.Zhang Yaxiong,Zhu Xiaomin,Zhang Gongcheng,et al. The sequence stratigraphic features of the Paleogene system Lingshui formation in Qiongdongnan Basin[J]. Petroleum Geology and Recovery Efficiency,2013,20(5):33-37.
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[4]李增学,张功成,王东东,等.海域区古近系含煤地层基准面旋回识别与对比:以琼东南盆地为例[J].现代地质,2010,24(6):1178-1186.Li Zengxue,Zhang Gongcheng,Wang Dongdong,et al. Identification and correlation of base-level cycles of coal-bearing strata in Paleogene system of China sea:Taking the case of Qiongdongnan basin as an example[J]. Geoscience,2010,24(6):1178-1186.
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[7]蔡国富,邵磊,乔培军,等.琼东南盆地古近纪海侵及沉积环境演化[J].石油学报,2013,34(2):91-101.Cai Guofu,Shao Lei,Qiao Peijun,et al. Marine transgression and evolution of depositional environment in the Paleogene strata of Qiongdongnan Basin,South China Sea[J]. Acta Petrolei Sinica,2013,34(S02):91-101.
[8]李增学,张功成,李莹,等.中国海域区古近纪含煤盆地与煤系分布研究[J].地学前缘,2012,19(4):314-326.Li Zengxue,Zhang Gongcheng,Li Ying,et al. The Paleogene coalbearing basin and coal-measures distribution of China sea area[J].Earth Science Frontiers,2012,19(4):314-326.
[9]蔡佳.琼东南盆地古近系古地貌恢复及其对层序样式和沉积特征的控制[D].武汉:中国地质大学资源学院,2009.Cai Jia. Morphologic restoration of Paleogene in Qiongdongnan Basin and its control on sequence architecture and sedimentary characteristics[D]. Wuhan:China University of Geosciences,2009.
[10]沈怀磊,张功成,孙志鹏,等.琼东南盆地深水区富气凹陷形成控制因素与勘探实践-以陵水凹陷为例[J].石油学报,2013,34(增刊2):83-90.Shen Huailei,Zhang Gongcheng,Sun Zhipeng,et al. Formation control factor analysis and exploration practice in gas-rich sag in deet-water areas of Qiongdongnan basin:a case study of Lingshui sag[J].Acta Petrolei Sinica,2013,34(S02):83-90.
[11]魏魁生,楚美娟,崔颖凯,等.琼东南盆地东部低位体系域的时空组合特征及油气勘探意义[J].石油与天然气地质,2004,25(06):650-655.Wei Kuisheng,Chu Meijuan,Cui Yingkai,et al. Characteristics of time-space combination of lowstand system tracts and their exploration significance in eastern Qiongdongnan basin[J]. Oil&Gas Geology,2004,25(06):650-655.
[12]张功成,何玉平,沈怀磊.琼东南盆地崖北凹陷崖城组煤系烃源岩分布及其意义[J].天然气地球科学,2012,23(4):654-661.Zhang Gongcheng,He Yuping,Shen Huailei. Research Significance and coal-measure source rock distribution of Yacheng Formation in Qiongdongnan Basin Ya-north sag[J]. Natural Gas Geoscience,2012,23(4):654-661.
[13]尚鲁宁,吕大炜,李增学,等.琼东南盆地崖南凹陷崖城组辫状河三角洲沉积特征及油气地质意义[J].油气地质与采收率,2013,20(5):4-9.Shang Luning,Lv Dawei,Li Zengxue,et al. Oil vapor geological significance and the braided river delta sedimentary characteristics of Yacheng Formation in Qiongdongnan Basin Ya-south sag[J]. Petroleum Geology and Recovery Efficiency,2013,20(5):4-9.
[14]刘文超,叶加仁,雷闯,等.琼东南盆地乐东凹陷烃源岩热史及成熟史模拟[J].地质科技情报,2011,30(6):110-115.Liu Wenchao,Ye Jiaren,Lei Chuang,et al. Geothermal and maturation histories modeling of the source rocks in the Ledong Sag,Qiongdongnan Basin[J]. Geological Science and Technology Information.2011,30(6):110-115.
[15]熊波,苏龙,张功成,等.琼东南盆地深水区崖城组煤系烃源岩定量评价[J].天然气地球科学,2014,25(4):542-550.Xiong Bo,Su Long,Zhang gongcheng,et al. Quantitative evaluation for coal-bearing source rocks of Yacheng Formation in the deep-water area of the Qiongdongnan Basin[J]. Natural Gas Geoscience,2014,25(4):542-550.
[16]张功成,李增学,何玉平,等.琼东南盆地煤地球化学特征[J].天然气地球科学,2010,21(5):693-699.Zhang Gongcheng,Li Zengxue,He Yuping,et al. Geochemical characteristics of coal in Qiongdongnan Basin[J]. Natural Gas Geoscience,2010,21(5):693-699.
[17]龚再升,李思田,谢泰俊,等.南海北部大陆边缘盆地分布与油气聚集[M].北京:科学出版社,1997:1-98.Gong Zaisheng,Li Sitian,Xie Taijun,et al. Continental margin basin analysis and hydrocarbon accumulation of the northern South China Sea[M]. Beijing:Science Press,1997:1-98.
[18]李增学,何玉平,刘海燕,等.琼东南盆地崖城组煤的沉积学特征与聚煤模式[J].石油学报,2010,31(4):542-547.Li Zengxue,He Yuping,Liu Haiyan,et al. Sedimentology characteristics and coal-forming models in Yacheng Formation of Qiongdongnan Basin[J]. Acta Petrolei Sinica,2010,31(4):542-547.
[19]李增学,宋广增,王东东,等.琼东南盆地渐新统煤系(扇)辫状河三角洲特征[J/OL].地球科学,2018,http://kns. cnki. net/kcms/detail/42. 1874. P. 20180730. 0955. 010. html.Li Zengxue,Song Guangzen,Wang Dongdong,et al. Characteristics of(fan)braided river delta in coal measures of Oligocene Yacheng Formation in Qiongdongnan basin[J/OL]. Geoscience,2018,http://kns. cnki. net/kcms/detail/42. 1874. P. 20180730. 0955. 010. html.
[20]宋广增,王华,孙志鹏,等.琼东南盆地深水区陵水凹陷古近纪同沉积断裂对层序构成样式的控制[J].中国石油大学学报(自然科学版),2014,38(4):9-18.Song Guangzeng,Wang Hua,Sun Zhipeng,et al. Paleogene sydepositional fault and its control on sequence architecture of Lingshui sag,deepwater area of Qiongdongnan basin South China Sea[J]. Journal of China Petroleum University(natural science edition),2014,38(4):9-18.
[21]李绪宣,李维新,张益明,等.琼东南盆地天然气成藏特征及地震识别技术[J].中国海上油气,2006,18(2):79-86.Li Xuxuan,Li Weixin,Zhang Yiming,et al. Gas accumulation characteristics and seismic identification techniques in Qiongdongnan basin[J]. China Offshore Oil and Gas,2006,18(2):79-86.
[22]谢文彦,张一伟,孙珍,等.琼东南盆地断裂构造与成因机制[J].海洋地质与第四纪地质,2007,27(1):71-78.Xie Wenyan,Zhang Yiwei,Sun Zhen,et al. Characteristics and formation mechanism of faults in Qiongdongnan basin[J]. Marine Geology and Quaternary Geology,2007,27(1):71-78.
[2] Franke D,Savva D,Pubellier M. The final rifting evolution in the South China Sea[J]. Marine and Petroleum Geology,2014,58:704-720.
[3] Hu Bo,Wang Liangshu,Yan Wenbo. The tectonic evolution of the Qiongdongnan Basin in the northern margin of the South China Sea[J]. Journal of Asian Earth Sciences,2013,77:163-182.
[4]李增学,张功成,王东东,等.海域区古近系含煤地层基准面旋回识别与对比:以琼东南盆地为例[J].现代地质,2010,24(6):1178-1186.Li Zengxue,Zhang Gongcheng,Wang Dongdong,et al. Identification and correlation of base-level cycles of coal-bearing strata in Paleogene system of China sea:Taking the case of Qiongdongnan basin as an example[J]. Geoscience,2010,24(6):1178-1186.
[5]赵东娜,朱筱敏,林金成,等.南海琼东南盆地崖13-1气田古近系陵水组海陆过渡带沉积特征及演化[J].古地理学报,2014,16(3):385-400.Zhao Dongna,Zhu Xiaomin,Lin Jincheng,et al. Sedimentary characteristics and evolution of transitional belt of the Paleogene LingshuiFormation in Ya13-1 Gasfield of Qiongdongnan Basin,South China Sea[J]. Journal of Palaeogeography,2014,16(3):385-400.
[6]邵磊,李昂,吴国暄,等.琼东南盆地沉积环境及物源演变特征[J].石油学报,2010,31(4):548-552.Shao Lei,Li Ang,Wu Guoxuan,et al. Evolution of sedimentary environment and provenance in Qiongdongnan Basin in the northern South China Sea[J]. Acta Petrolei Sinica,2010,31(4):548-552.
[7]蔡国富,邵磊,乔培军,等.琼东南盆地古近纪海侵及沉积环境演化[J].石油学报,2013,34(2):91-101.Cai Guofu,Shao Lei,Qiao Peijun,et al. Marine transgression and evolution of depositional environment in the Paleogene strata of Qiongdongnan Basin,South China Sea[J]. Acta Petrolei Sinica,2013,34(S02):91-101.
[8]李增学,张功成,李莹,等.中国海域区古近纪含煤盆地与煤系分布研究[J].地学前缘,2012,19(4):314-326.Li Zengxue,Zhang Gongcheng,Li Ying,et al. The Paleogene coalbearing basin and coal-measures distribution of China sea area[J].Earth Science Frontiers,2012,19(4):314-326.
[9]蔡佳.琼东南盆地古近系古地貌恢复及其对层序样式和沉积特征的控制[D].武汉:中国地质大学资源学院,2009.Cai Jia. Morphologic restoration of Paleogene in Qiongdongnan Basin and its control on sequence architecture and sedimentary characteristics[D]. Wuhan:China University of Geosciences,2009.
[10]沈怀磊,张功成,孙志鹏,等.琼东南盆地深水区富气凹陷形成控制因素与勘探实践-以陵水凹陷为例[J].石油学报,2013,34(增刊2):83-90.Shen Huailei,Zhang Gongcheng,Sun Zhipeng,et al. Formation control factor analysis and exploration practice in gas-rich sag in deet-water areas of Qiongdongnan basin:a case study of Lingshui sag[J].Acta Petrolei Sinica,2013,34(S02):83-90.
[11]魏魁生,楚美娟,崔颖凯,等.琼东南盆地东部低位体系域的时空组合特征及油气勘探意义[J].石油与天然气地质,2004,25(06):650-655.Wei Kuisheng,Chu Meijuan,Cui Yingkai,et al. Characteristics of time-space combination of lowstand system tracts and their exploration significance in eastern Qiongdongnan basin[J]. Oil&Gas Geology,2004,25(06):650-655.
[12]张功成,何玉平,沈怀磊.琼东南盆地崖北凹陷崖城组煤系烃源岩分布及其意义[J].天然气地球科学,2012,23(4):654-661.Zhang Gongcheng,He Yuping,Shen Huailei. Research Significance and coal-measure source rock distribution of Yacheng Formation in Qiongdongnan Basin Ya-north sag[J]. Natural Gas Geoscience,2012,23(4):654-661.
[13]尚鲁宁,吕大炜,李增学,等.琼东南盆地崖南凹陷崖城组辫状河三角洲沉积特征及油气地质意义[J].油气地质与采收率,2013,20(5):4-9.Shang Luning,Lv Dawei,Li Zengxue,et al. Oil vapor geological significance and the braided river delta sedimentary characteristics of Yacheng Formation in Qiongdongnan Basin Ya-south sag[J]. Petroleum Geology and Recovery Efficiency,2013,20(5):4-9.
[14]刘文超,叶加仁,雷闯,等.琼东南盆地乐东凹陷烃源岩热史及成熟史模拟[J].地质科技情报,2011,30(6):110-115.Liu Wenchao,Ye Jiaren,Lei Chuang,et al. Geothermal and maturation histories modeling of the source rocks in the Ledong Sag,Qiongdongnan Basin[J]. Geological Science and Technology Information.2011,30(6):110-115.
[15]熊波,苏龙,张功成,等.琼东南盆地深水区崖城组煤系烃源岩定量评价[J].天然气地球科学,2014,25(4):542-550.Xiong Bo,Su Long,Zhang gongcheng,et al. Quantitative evaluation for coal-bearing source rocks of Yacheng Formation in the deep-water area of the Qiongdongnan Basin[J]. Natural Gas Geoscience,2014,25(4):542-550.
[16]张功成,李增学,何玉平,等.琼东南盆地煤地球化学特征[J].天然气地球科学,2010,21(5):693-699.Zhang Gongcheng,Li Zengxue,He Yuping,et al. Geochemical characteristics of coal in Qiongdongnan Basin[J]. Natural Gas Geoscience,2010,21(5):693-699.
[17]龚再升,李思田,谢泰俊,等.南海北部大陆边缘盆地分布与油气聚集[M].北京:科学出版社,1997:1-98.Gong Zaisheng,Li Sitian,Xie Taijun,et al. Continental margin basin analysis and hydrocarbon accumulation of the northern South China Sea[M]. Beijing:Science Press,1997:1-98.
[18]李增学,何玉平,刘海燕,等.琼东南盆地崖城组煤的沉积学特征与聚煤模式[J].石油学报,2010,31(4):542-547.Li Zengxue,He Yuping,Liu Haiyan,et al. Sedimentology characteristics and coal-forming models in Yacheng Formation of Qiongdongnan Basin[J]. Acta Petrolei Sinica,2010,31(4):542-547.
[19]李增学,宋广增,王东东,等.琼东南盆地渐新统煤系(扇)辫状河三角洲特征[J/OL].地球科学,2018,http://kns. cnki. net/kcms/detail/42. 1874. P. 20180730. 0955. 010. html.Li Zengxue,Song Guangzen,Wang Dongdong,et al. Characteristics of(fan)braided river delta in coal measures of Oligocene Yacheng Formation in Qiongdongnan basin[J/OL]. Geoscience,2018,http://kns. cnki. net/kcms/detail/42. 1874. P. 20180730. 0955. 010. html.
[20]宋广增,王华,孙志鹏,等.琼东南盆地深水区陵水凹陷古近纪同沉积断裂对层序构成样式的控制[J].中国石油大学学报(自然科学版),2014,38(4):9-18.Song Guangzeng,Wang Hua,Sun Zhipeng,et al. Paleogene sydepositional fault and its control on sequence architecture of Lingshui sag,deepwater area of Qiongdongnan basin South China Sea[J]. Journal of China Petroleum University(natural science edition),2014,38(4):9-18.
[21]李绪宣,李维新,张益明,等.琼东南盆地天然气成藏特征及地震识别技术[J].中国海上油气,2006,18(2):79-86.Li Xuxuan,Li Weixin,Zhang Yiming,et al. Gas accumulation characteristics and seismic identification techniques in Qiongdongnan basin[J]. China Offshore Oil and Gas,2006,18(2):79-86.
[22]谢文彦,张一伟,孙珍,等.琼东南盆地断裂构造与成因机制[J].海洋地质与第四纪地质,2007,27(1):71-78.Xie Wenyan,Zhang Yiwei,Sun Zhen,et al. Characteristics and formation mechanism of faults in Qiongdongnan basin[J]. Marine Geology and Quaternary Geology,2007,27(1):71-78.