【作者】 宋华颖；

【导师】 伊海生；

【作者基本信息】 成都理工大学 ， 沉积学， 2010， 硕士

【摘要】 上扬子区包括四川、贵州省大部分、云南省东部和湖南省西部,是我国沉积岩最发育的地区之一。上扬子地台北缘地跨川、陕、渝边界一带,地处四川盆地东北部,北邻东西向秦岭造山带,西接松潘—甘孜造山带和北东向龙门山推覆构造带,东侧为大巴山北西—南东向弧形推覆构造带,南侧为四川盆地缓变形区。研究区位于上扬子地台北缘,区域构造在川北大巴山前陆盆地与川中隆起之间的斜坡带上,北邻米仓山冲断隆起带和旺苍南江构造带,东接川东高陡构造带,南为仪陇平昌平缓构造带。本文对区内晚震旦世灯影组三四段及古生界16条沉积剖面的沉积相及不同时代,不同构造性质的烃源岩地层进行了系统采样,烃源岩特征分析。主要工作、认识和成果概括如下:1、收集、分析整理了扬子地台研究的大量前人资料,在此基础上对上扬子地台北缘地质背景、沉积、构造、地层分析整理和综合并进行了再认识。2、收集、整理、对比了上扬子地台北缘重要区域古生界地层与研究区的地层。3、研究区古生界地层是一套以碳酸盐岩为主的地层,其中又以石灰岩占绝对优势,白云岩较少。石灰岩按照其结构组分和某些特殊成因,可进一步划分为颗粒—泥晶灰岩、礁灰岩、龟裂纹灰岩、瘤状灰岩和重力流石灰岩等。白云岩按晶粒大小可分为泥晶白云岩和粉晶白云岩两种。另外出露的岩石还有碎屑岩,可进一步划分为砾岩、砂岩、粉砂岩、泥（页）岩;硅质岩大部分出现于下寒武统中下部及上二叠统,以黑色、黑灰色薄—中层状为主。4、研究区寒武纪主要为陆棚、台地沉积环境。碳酸盐潮坪相以大巴山前缘明庙坝剖面为典型代表;开阔台地相以米仓山前缘旺苍地区剖面为代表。台缘斜坡亚则以大巴山前缘万源地区剖面为代表;奥陶系上统五峰组—志留系下统龙马溪组的下部,均属陆棚内盆地沉积相;晚奥陶世五峰期之前主要发育碳酸盐台地相;志留系以正常滨浅海相碎屑岩和碳酸盐岩沉积为主,上志留统缺失。龙马溪组（双河场组）主要是深水陆棚或者陆棚内盆地沉积,罗惹坪组（徐家坝组）主要为浅水陆棚和滨岸相沉积;二叠系主要沉积相可包括:滨岸沼泽相、局限台地沉积相、开阔台地相、台地边缘礁滩相、碳酸盐岩缓坡相和台盆相。5、结合区内烃源岩均处于高—过成熟的特点及前人的认识,本文选用泥质岩TOC含量0.3%,碳酸盐岩TOC含量0.2%作为有效烃源岩下限值,即区内烃源岩生气下限值。据此得出上扬子地台北缘烃源岩地层有下二叠统茅口组（P1m）,下志留统龙马溪组（S₁ln）,上奥陶统五峰组（O₃w）,上奥陶统临湘组（O₃l）,下寒武统郭家坝组（∈1g）及下寒武统水井沱组（∈1s）。6、根据干酪根碳同位素特征及干酪根镜鉴显微组分特征综合分析,上扬子地台北缘烃源岩主要为生烃能力较强的Ⅰ型、Ⅱ1型。镜质体反射率、热解峰值温度Tmax、H/C原子比及干酪根颜色表明,区内烃源岩均处于高—过成熟阶段,以过成熟烃源岩为主,但并未达到陈建平等人提出的“生气死亡线”Ro值3.0%,仍具有生气能力。7、从岩性特征,烃源岩有机质丰度、有机质类型、有机质成熟度等有机地球化学研究,对烃源岩进行初步评价。下寒武统黑色泥岩及下二叠统碳酸盐岩在上扬子地台北缘一带分布广泛,厚度较大,有机质丰度高,有机质类型好,是区内的主力烃源岩地层;下志留统及上奥陶统黑色泥页岩虽厚度不大,但其有机质丰度很高,局部地区可能存在有利的烃源岩发育段;上奥陶统临湘组分布不广,有机质丰度不高,生烃潜力不大。综合评价认为下寒武统及下二叠统是区内的主力烃源岩地层;下志留统及上奥陶统在局部地区可能存在有利的烃源岩发育段。8、一定的沉积环境只能出现一定的沉积物组合,而这些沉积物中的有机质则是油气形成的物质基础。因此,烃源岩分布的先天条件取决于沉积相的特征。据研究区下寒武统、上奥陶统、下志留统、下二叠统四套古生代海相烃源岩的研究,得出研究区内5种有利烃源岩发育的沉积相:即深水泥质陆棚相、深水碳酸盐岩陆棚相、深水硅磷质台盆相、海湾泻湖相、近海湖盆沼泽相。更多还原

【Abstract】 The Yangtze region, including Sichuan, most of Guizhou Province ,eastern Yunnan and western Hunan Province, is China’s most developed regions of sedimentary rocks. Margin of the Yangtze across Sichuan, Shaanxi, Chongqing and along the border, is located in the Sichuan Basin, northeast, north east-west Qinling orogenic belt, west of Songpan - Ganzi orogenic belt and the North East to the Longmen Shan nappe, east To Daba North West - South East to arc nappe, south of slow deformation zone for the Sichuan Basin. Study area is located on the margin of the Yangtze, the regional tectonic Daba Mountains in northern Sichuan and Sichuan foreland basin between the slope of uplift, north Micangshan thrust uplift and wangcang South River tectonic zone, east, eastern Sichuan steep tectonic belt, south Yilong Pyeongchang flat belt. In this paper, the area of the Late Sinian Dengying 3 Siduan and Palaeozoic sedimentary profile 16 sedimentary facies and different times, different structural nature of the source rock strata a systematic sample, source rock characteristics. Major work, knowledge and results summarized as follows:1、Collection, and analysis of the Yangtze platform of a large number of data available, in this based on the margin of the Yangtze geological setting, sedimentary, tectonic, stratigraphic analysis and synthesis of order and conduct a re-understanding.2、Collection, collation, comparison of the upper margin of the Yangtze important regional Paleozoic strata and the study area.3、Paleozoic strata in the study area is a set of mainly carbonate strata, among them, absolute advantage in limestone, dolomite less. Limestone structure in accordance with its components and some special causes can be further divided into: Particles– micrite、Reef limestone、Turtle crack limestone、Nodular limestone、Gravity flow limestone,etc. Dolomite can be divided micritic dolomite and silty dolostone, according to grain size. Also exposed are clastic rocks.It can be further divided into conglomerates, sandstones, siltstone, clay (shale). Most cherts occur in the lower part of Lower Cambrian and Upper Permian, black, dark gray thin - mainly in the layer.4、Study area is mainly Cambrian continental shelf, platform depositional environment. Carbonate tidal-flat facies in Daba Mountain front for the next temple typical dam section; Open platform facies to section Micangshan front wangcang region represented; Platform margin slope facies Wanyuan in front of Daba mounta in profile to represent the source region. On the system Ordovician Wufeng Formation - Silurian system Longmaxi under the lower part of the land shed basin facies are sedimentary subfacies; Wufeng Late Ordovician carbonate platform of development before the main phase. Silurian to normal littoral and shallow marine clastic and carbonate rocks deposited mainly , the Silurian missing. Longmaxi (shuanghechang group ) is mainly deep water shelf or land shed basin, shallowing upward sedimentary.Rojak Ping group (Xujiaba group) is mainly shallow shelf and littoral facies. Permian sedimentary facies mainly include: coastal marsh facies sedimentary facies restricted platform, open platform, platform margin reef facies, carbonate ramp and basin phase.5、In combination with the source rocks are in the characteristics of a high - mature understanding and predecessors, this selection TOC content is 0.3% of mudstone, carbonate content of 0.2% TOC, as the lower limit of effective source rocks, hydrocarbon source rocks in the area that is under the limit. Thus obtained on the margin of the Yangtze effective source rocks are Lower Permian strata Maokou, Lower Silurian Longmaxi, Upper Ordovician Wufeng formation, Upper Ordovician Linxiang formation, Lower Cambrian Guo Jiaba formation, Lower Cambrian Shui Jingtuo formation.6、According to carbon isotope geochemistry of kerogen and kerogen maceral characteristics Mirroring comprehensive analysis, on the margin of the Yangtze main living hydrocarbon source rocks are relatively strong typeⅠ,Ⅱ1 type. Vitrinite reflectance, pyrolysis peak temperature Tmax, H / C atomic ratio and the color of kerogen indicate that source rocks of the region are at high - over mature stage.In the region to over-mature source rocks in the main hydrocarbon source rock, but did not reach Chen Jinping, who raised "Dead line of oil and gas production" Ro value of 3.0%, still has the ability to produce oil and gas.7、From the lithology, source rock organic matter abundance, organic matter type, maturity of organic matter and organic geochemical studies on the preliminary evaluation of source rocks. Lower Cambrian black shale and Lower Permian carbonate rocks in the vicinity of the Yangtze margin are of widespread, thick, high abundance of organic matter, organic matter type is good, the region’s main source rock strata; Lower Silurian and Upper Ordovician black shale though much thickness, but the high abundance of organic matter in some areas there may be a favorable section of hydrocarbon source rocks; Upper Ordovician Linxiang group are not widely distributed, low abundance of organic matter, little hydrocarbon potential. Comprehensive evaluation that the Lower Cambrian and Lower Permian is the main source area strata; Lower Silurian and Upper Ordovician, there may be beneficial in some areas of hydrocarbon source rock section.8、Certain depositional environment of sediments can only have certain combinations of organic matter in these sediments is the material basis for the formation of oil and gas. Therefore, the innate distribution of source rocks is determined by characteristics of sedimentary facies. According to the study area of the Lower Cambrian, Upper Ordovician, Lower Silurian, Lower Permian four Paleozoic marine source rock studies, obtained in the study area five kinds of favorable hydrocarbon source rocks of sedimentary facies: Deep muddy continental shelf, deep shelf carbonate facies, deep silicon phosphorus basin with the Gulf lagoon, offshore basin swamp.更多还原