【作者】 吴浩；

【导师】 姚素平；

【作者基本信息】 南京大学 ， 地球化学， 2014， 硕士

【摘要】 本文在对北美和上扬子页岩气评价参数调研的基础上,开展了安徽扬子地层区页岩气调查评价工作。开展了系统的野外剖面实测和采样工作,搜集了区内有关的钻井剖面和地质报告资料,同时对三口钻井进行了岩心观察与取样,并开展了各种与页岩气有关的室内测试和分析。在此基础上,对研究区的构造演化、目的页岩层系的沉积环境和展布特征以及页岩气的各种评价参数进行了系统研究。通过与北美和上扬子页岩气地质条件和开采条件的对比,提出了页岩气勘探有利区。论文主要结论和成果如下：1、下扬子地区在古生代经历了三种构造背景,形成三种类型的盆地,分别是震旦纪-中奥陶世的被动陆缘的台地-斜坡,晚奥陶世-志留纪的前陆盆地和晚古生代的内克拉通盆地。盆地均以海相碳酸盐和碎屑岩为主,其中主要发育了下寒武统、上奥陶统-下志留统和中上二叠统三套黑色岩系。2、研究区下寒武统荷塘组主要为台地-斜坡相沉积,地层厚度总体从北西向南东方向越来越厚,黄山石台一带黑色泥页岩厚度均超过200米,最厚超过600米；早志留世为一前陆盆地,总体上来看,高家边黑色泥页岩厚度以北北东向从北西到南东地层厚度越来越厚,黄山一带较厚,可达254米,巢湖、滁州一带较薄：龙潭期为一克拉通盆地,沉积厚度由北东至南西向逐渐减少,其中宣泾地区沉积厚度最大,约200米左右。3、研究区泥页岩有机质丰度均值大于2.00%,下寒武统和下志留统有机质以Ⅰ型为主,孤峰组和大隆组为Ⅰ-Ⅱ型有机质,龙潭组主要为Ⅲ型有机质。下古生界页岩成熟度普遍达到过成熟状态,中上二叠统成熟度大部分在1.3-2.0%,处于成熟到高成熟阶段。4、研究区三套泥质烃源岩X衍射实验结果表明：泥页岩中石英、长石和黄铁矿的平均含量为77%-94%,碳酸盐矿物的平均含量低于20%,粘土矿物平均含量为5%-23%；页岩孔隙发育,包括有机质孔、矿物质孔和次生孔／缝3类。泥页岩样品的等温吸附试验表明龙潭组泥岩兰氏体积(VL)为3.64m3/t,五峰组页岩兰氏体积(VL)为1.42m3/t,荷塘组页岩兰氏体积(VL)为2.33m3/t。5、通过与北美页岩气和上扬子龙马溪组页岩地质参数的对比,运用综合因素得分评价方法,将安徽下扬子划分为9个盆地(向斜),共21个评价单元进行打分,各项参数综合显示宣广盆地中上二叠统孤峰组-龙潭组-大隆组为区内最有利的目标勘探区。更多还原

【Abstract】 The evaluation parameters of gas shales used in North America and upper Yangtze region, China are utilized to evaluate the lower Yangtze area in Anhui Province. Sections measuring and sampling are conducted in fieldwork and geological data related to potential gas shales in the study area are collected. Core samples in three wells are collected and used for many experiments that associated with gas shales evaluation. Systematic research about the evaluation parameters, sedimentary environment and distribution features of target formations and tectonic evolution in the research area have been conducted. By comparing the shale gas geological and mining conditions with North America and upper Yangtze area, we proposed the area with highest shale gas potential. Our main conclusions are as follows:1. Lower Yangtze region has experienced three stages of tectonic evolution in Paleozoic, developing three types of basins. They are passive margin of Late Qrdovician-Sinian, foreland basin of the Late Ordovician-Silurian and Late Paleozoic craton basins, mainly developing the Lower Cambrian strata, the Upper Ordovician-the Lower Sinian strata and upper Permian strata respectively.2. Hetang formation, lower Cambrian mainly developed platform-clinothem facies. The strata thickness increases from the Northwest to the Southeast in the study area. The thickness of the black shales in Huangshan and Shitai area are more than 200 m while the largest thickness is more than 600 m. The Early Silurian developed a foreland basin. Overall, the thickness of Gaojiabian formation balck shale increases from the Northwest to the Southeast in the study area. The shale thickness in Huangshan area can be up to 254 m which is thicker than Chuzhou-Chaohu area. The thickness of Longtan formation decreases from the North east to the Southwest in the study area. It is about 200 m in Xuancheng-Jingxian area.3. The mean value of TOC is larger than 2.00% of the black shale in the study area. The organic matter of lower Cambrian and lower Silurian is mainly type I, and Gufeng and Dalong formation is mainly type I-II and Longtan formation is mainly type III.The Lower Paleozoic shales are generally over-matured and the Ro value of upper Permian is mostly from 1.3-2.0% which suggested mature to high-mature stage.4. X-ray diffraction results show that the average content of quartz, feldspar and pyrite of study strata is 77%-94%; the average content of carbonate minerals is below 20%; and clay mineral content is 5%-23% in average. Shale pore can be divided into organic pore, mineral pore and secondary pore/seam. The adsorption isothermal experiments show that the VL of Longtan, Wufeng and Hetang formations are 3.64 m3/t,1.42m3/t and 2.33 m3/t respectively.5. By comparing shale gas geological parameters with North American shale and Longmaxi shale in upper Yangtze region, many factors are taken into consideration for evaluating the study area. The study area is divided into 9 basins (syncline),21 units in total, and Gufeng-Longtan-Dalong Formations in Xuanguang Basin are proposed to be the most favorable exploration area.更多还原