2016年2期

鄂西宜昌地区埃迪卡拉系陡山沱组页岩沉积环境及其页岩气地质意义

发布时间:2016-09-05阅读次数:

【期数】2016-2

【作者】陈孝红,张国涛,胡 亚

【机构】中国地质调查局武汉地质调查中心,武汉430205

【关键词】页岩气;沉积环境;埃迪卡拉系;陡山沱组;宜昌地区

【中文摘要】基于鄂西宜昌黄陵隆起周缘不同古地理部位埃迪卡拉系陡山沱组剖面的野外调查,岩石矿物和碳同位素样品的成分分析,页岩地球化学分析和物性实验结果,系统研究宜昌地区埃迪卡拉系陡山沱组二段页岩地层格架与分布、形成环境、地球化学和页岩气储集层特征。结果表明峡东宜昌地区在埃迪卡拉系陡山沱组二段下部页岩沉积于氧化环境,而中上部黑色页岩沉积形成于还原环境,碳酸盐是甲烷泄漏的结果。陡山沱组二段暗色泥页岩地层厚度超过50 m,有机碳含量(TOC)普遍大于1 %,局部地区超过2 %,有机质类型以I型和Ⅱ1型为主,成熟度(Ro)Ro变化于1.58%-% ~ 2.38%之间;矿物成分主要为碎屑矿物。与美国和中国页岩气主产区的页岩指标相比较,宜昌地区陡山沱组二段泥页岩具有形成页岩气良好地质条件。

【英文摘要】Based on the systematic investigated in the field geological sections, together with the result of organic geochemistry experiment, physical analysis and the component analysis of the rock mineral and carbonate isotopic samples, the characteristics of sedimentary environments, the scale of development, geochemistry and reservoir of the Ediacaran Doushantuo Formation shale in the different position of the Huangling anticline in Yichang were systematically studied .The results show that the black shale in the lower and upper of the Doushantuo Formation Member 2 were deposited separately in an oxic and a reduced environment, and the carbonate interval bed in the middle of the Doushantuo Formation Member 2 were the result of destabilization of methane hydrates during deglaciation and concomitant flooding of interior basins. The thickness of Doushantuo Foramtion black mud shale is more than 50 m, the total organic content is generally over 1.0%, the main organic type is I-Ⅱ1, the average value of organic material maturity (RbRo) is 2.45%, and the black mud shale is mainly composed of detrital minerals. Compared with the indicators of the main shale gas production areas in the USA and China, Ediacaran Doushantuo Formation member2 mud black shale in Yichang area has the good geological conditions for producing shale gas.

【文章下载】点击打开

396908