Based on detail analysis of data of well logging, seismic records, outcrops and cores, the relationship between shale-member sedimentary facies and total organic carbons(TOC) of the Lower Silurian in Middle-Upper Yangtze area was discussed, and the favourable exploration directions were predicted. The Lower Silurian Longmaxi Formation consists of black shales interbedded with greenish-gray mudy siltstones, with the thickness of 20~268 m, in Middle-Upper Yangtze area, and two third-order stratigraphy sequences of SQ1 and SQ2, which distributed|stably could be|easily correlated, were distinguished from bottom to top within synchronous|stratigraphic framework. The transgressive systems tract(TST)of lower sequence SQ1 developed a set of organic-rich shale which is favorable for shale gas. During the depositional period of TST, the sedimentary pattern can be described as “abyss-area was open towards north, old lands were located in the east, south and west, deep shelf distributed extensively”, with the deep shelf area of 255 000 km2, and the average thickness of 35 m. Affected by the fall of sea-level, the shallowing of water took place, and lithofacies changed from black shales of deep shelf to laminated silty shales of middle and shallow shelf facies from the lower sequence to the upper sequence. The development of lithofacies was controlled by eustacy of sea-level, old lands, sea-bottom topography and sediment supply, and five lithofacies types including carbonaceous or siliceous or calcareous shales, laminated shales, biologic-stirred silty shales, laminated silty shales and interbeds of massive sandstones or shell limestones were developed. It was proved that the forming of organic-rich shales were intrinsically controlled by sedimentary facies, with deep shelf, middle shelf and lagoon generating high|content of TOC. So far, there were several wells of industry gas flow from the Longmaxi Formation, which had revealed well exploration prospect, for the Middle-Upper Yangtze area. It is synthetically concluded that zones of Fuling-Shishui-Renhuai, Weiyuan-Changning and western Hubei Province-eastern Sichuan Province are the main exploration directions and favorable targets of shale gas in the Lower Silurian of Middle-Upper Yangtze area.
About author: Zheng Herong, born in 1962, doctor, professor senior engineer, vice director of Institute of Petroleum Exploration and Production, Sinopec. He is engaged in subtle hydrocarbon reservoirs, unconventional hydrocarbon geology, and supervisor of grave exploration and production. Tel: 010-82312026;E-mail: Zhengherong. syky@sinopec.com.
Cite this article:
Zheng Herong,Gao Bo,Peng Yongmin et al. Sedimentary evolution and shale gas exploration direction of the Lower Silurian in Middle-Upper Yangtze area[J]. JOPC, 2013, 15(5): 645-656.
Zheng Herong,Gao Bo,Peng Yongmin et al. Sedimentary evolution and shale gas exploration direction of the Lower Silurian in Middle-Upper Yangtze area[J]. JOPC, 2013, 15(5): 645-656.
陈旭, 戎嘉余, 周志毅. 2001. 上扬子区奥陶—志留纪之交的黔中隆起和宜昌上升[J]. 科学通报, 46(12): 1052-1056. 董大忠, 程克明, 王世谦, 等. 2009. 页岩气资源评价方法及其在四川盆地的应用[J]. 天然气工业, 29(5): 33-39. 冯增昭, 彭勇民, 金振奎, 等. 2001. 中国南方早奥陶世岩相古地理[J]. 古地理学报, 3(2): 11-22. 冯增昭, 彭勇民, 金振奎, 等. 2004. 中国寒武纪和奥陶纪岩相古地理[M]. 北京:地质出版社, 1-276. 高振中, 何幼斌, 李罗照. 2008. 中国南方上奥陶统五峰组观音桥段成因讨论:是“浅水介壳相”, 还是深水异地沉积?[J]. 古地理学报, 10(5): 487-494. 郭旭升, 郭彤楼, 魏志红, 等. 2012. 中国南方页岩气勘探评价的几点思考[J]. 中国工程科学, 14(6): 101-105. 郭英海, 李壮福, 李大华, 等. 2004. 四川地区早志留世岩相古地理[J]. 古地理学报, 6(1): 20-29. 黄金亮, 邹才能, 李建忠, 等. 2012. 川南志留系龙马溪组页岩气形成条件与有利区分析[J]. 煤炭学报, 37(5): 782-787. 李新景, 胡素云, 程克明. 2007. 北美裂缝性页岩气勘探开发的启示[J]. 石油勘探与开发, 34(4): 392-400. 李一凡, 樊太亮, 高志前, 等. 2012. 渝东南地区志留系黑色页岩层序地层研究[J]. 天然气地球科学, 23(2): 299-306. 梁狄刚, 郭彤楼, 陈建平, 等. 2008. 中国南方海相生烃成藏研究的若干新进展(一):南方四套区域性海相烃源岩的分布[J]. 海相油气地质, 13(2): 1-16. 梁狄刚, 郭彤楼, 陈建平, 等. 2009. 中国南方海相生烃成藏研究的若干新进展(三):南方四套区域性海相烃源岩的沉积相及发育的控制因素[J]. 海相油气地质, 14(2): 1-19. 刘宝珺, 许效松. 1994. 中国南方岩相古地理图集(震旦纪—三叠纪)[M]. 北京: 科学出版社, 1-239. 马永生, 陈洪德, 王国力. 2009. 中国南方层序地层与古地理[M]. 北京:科学出版社, 254-280. 马永生, 冯建辉, 牟泽辉, 等. 2012. 中国石化非常规油气资源潜力及勘探进展[J]. 中国工程科学, 14(6): 101-105. 聂海宽, 包书景, 高波, 等. 2012. 四川盆地及其周缘下古生界页岩气保存条件研究[J]. 地学前缘, 19(3): 280-294. 王鸿祯. 1985. 中国古地理图集[M]. 北京:地图出版社. 王社教, 杨涛, 张国生, 等. 2012. 页岩气主要富集因素与核心区选择及评价[J]. 中国工程科学, 14(6): 94-100. 王玉满, 董大忠, 李建忠, 等. 2012. 川南下志留统龙马溪组页岩气储集层特征[J]. 石油学报, 33(4): 551-561. 许效松, 刘伟, 周棣康, 等. 2009. 黔中—黔东南地区下志留统沉积相[J]. 古地理学报, 11(1): 13-20. 页岩气地质与勘探开发实践丛书编委会. 2009. 北美地区页岩气勘探开发新进展[M]. 北京:石油工业出版社, 41-224. 张春明, 张维生, 郭英海. 2012. 川东南—黔北地区龙马溪组沉积环境及对烃源岩的影响[J]. 地学前缘, 19(1): 136-145. 郑和荣, 胡宗全. 2010. 中国前中生代构造—岩相古地理图集[M]. 北京:地质出版社, 1-194. 邹才能, 董大忠, 王社教, 等. 2010. 中国页岩气形成机理、地质特征及资源潜力[J]. 石油勘探与开发, 37(6): 641-653. Bennett R H, OBrien N R, Hulbert M H. 1991. Determinants of clay and shale microfabric signatures:Processes andmechanisms[A]. In: Bennett R H, Bryant W R, Hulbert M H(eds). Microstructure of Fine-grained Sediments. New York, Springer Verlag: 5-32. Curtis J B. 2002. Fractured shale-gas systems[J]. AAPG Bulletin, 86(11): 1921-1938. Hammes U, Hamlin H S, Ewing T E. 2011. Geologic analysis of the Upper Jurassic Haynesville Shale in east Texas and west Louisiana[J]. AAPG Bulletin, 95(10): 1643-1666. Kinley T J, Cook W L, Breyer A J, et al. 2008. Hydrocarbon potential of the Barnett Shale(Mississippian), Delaware Basin, west Texas and southeastern New Mexico[J]. AAPG Bulletin, 92(8): 967-991. Loucks R G, Reed R M, Ruppel S C, et al. 2009. Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale[J]. Journal of Sedimentary Research, 79: 848-861. Lynne E, Ibach J. 1982. Relationship between sedimentation rate and total organic carbon content in ancient marine sediments[J]. AAPG Bulletin, 66: 170-188. Martineau D F. 2007. History of the Newark East field and the Barnett Shale as a gas reservoir[J]. AAPG Bulletin, 91(4): 399-403. Meyers P A. 2006. Paleoceanographic and paleoclimatic similarities between Mediterranean sapropels and Cretaceous black shales[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 235: 305-320. Milner M R, McLin J P. 2010. Imaging texture and porosity in mudstones and shales: Comparison of secondary and ion-milled backscatter SEM methods[C]. Calgary: Canadian Unconventional Resources & International Petroleum Conference. Montgomery S L, Jarvie D M, Bowker K A, et al. 2005. Mississippian Barnett Shale, Fort Worth basin, north-central Texas: Gas-shale play with multi-trillion cubic foot potential[J]. AAPG Bulletin, 89(2): 155-175. Robert G L, Stephen C R. 2007. Mississippian Barnett Shale: Lithofacies and depositional setting of a deep-water shale-gas succession in the Fort Worth Basin, Texas[J]. AAPG Bulletin, 91(4): 579-601. Stevenson D L, Dickerson D R. 1969. Organic geochemistry of the New Albany Shale in Illinois[R]. Illinois State Geological Survey, Illinois Petroleum, 90: 1-11. Stow D A V. 1981. Fine-grained sediments: Terminology[J]. Quaternary Journal of Engineering Geology, 14: 243-244.