河北省北部页岩样品纳米级孔隙结构及其影响因素

发布时间：2018-02-16 12:34

本文关键词： 页岩气孔隙结构 TOC 黏土矿物比例关系　出处：《天然气地球科学》2017年06期 　论文类型：期刊论文

【摘要】：页岩孔隙结构影响到页岩气资源前景乃至后期开发工程,其中纳米级孔隙是主要研究对象。采集不同层系23件黑色页岩样品,对其物质组成和小于100nm孔隙的结构进行测试。结果显示:石炭系—二叠系山西组、太原组样品的总有机碳(TOC)平均含量低于上元古界洪水庄组和下马岭组样品,黏土矿物含量普遍高于洪水庄组和下马岭组并含有大量高岭石,平均孔比表面积和孔容由高到低依次为洪水庄组、下马岭组、山西组和太原组。黏土矿物含量、种类和TOC均显著影响到页岩的孔隙结构:在TOC2%、2%~4.58%和4.58%3个分布段,页岩样品孔比表面积和孔容与黏土矿物含量之间分别呈正相关关系,与TOC含量呈负相关关系;当TOC含量4.58%时,TOC含量变化对孔隙结构的影响更为明显;而当TOC含量2%时,黏土矿物含量和种类对孔隙结构的影响更为明显,其中以伊利石含量的影响为主,高岭石含量的影响较小。发现TOC含量/黏土矿物含量之比与孔比表面积和孔容的相关性良好,指示与有机质丰度增高引起的孔比表面积和孔容变化相比,黏土矿物含量增高对孔隙结构的改善效应更为明显,两者的分布关系也是孔隙结构的重要指示影响因素和表征。研究认为,山西组和太原组页岩孔隙结构受黏土矿物特征影响较大,下马岭组和洪水庄组页岩孔隙结构则更多地受到TOC含量的影响。
[Abstract]:The pore structure of shale affects the prospects of shale gas resources and even the later development projects, among which nanometer pore is the main research object. 23 black shale samples from different layers were collected. The results show that the average content of total organic carbon (TOC) in the samples of the Carboniferous Permian Shanxi formation and Taiyuan formation is lower than that of the samples of the Upper Proterozoic Fumuzhuang formation and the Lower Maling formation. The clay mineral content is generally higher than that of the Hongzhuang formation and the Xiamaling formation, and contains a large amount of kaolinite. The average pore specific surface area and pore volume from high to low are in the order of the Fongzhuang formation, the Xiamaling formation, the Shanxi formation and the Taiyuan formation. Species and TOC significantly affected the pore structure of shale: in the three distribution segments of TOC _ 2 and TOC _ 2, the pore specific surface area and pore volume of shale samples were positively correlated with clay content, and negatively correlated with TOC content. When the content of TOC is 4.58, the effect of the content of TOC on pore structure is more obvious, but when the content of TOC is 2, the effect of clay content and species on pore structure is more obvious, especially the content of Illite. The effect of kaolinite content on the content of kaolinite is small. It is found that the ratio of TOC content to clay content has a good correlation with the pore specific surface area and pore volume, indicating that the ratio of TOC content to clay content is different from the change of pore specific surface area and pore volume caused by the increase of organic matter abundance. The effect of the increase of clay mineral content on the improvement of pore structure is more obvious, and the distribution relationship between them is also an important indicator and characterization of pore structure. The shale pore structure of Shanxi formation and Taiyuan formation is greatly affected by clay mineral characteristics, while the shale pore structure of Xiamaling formation and Hongzhuang formation is more affected by TOC content.
【作者单位】：中国矿业大学煤层气资源与成藏过程教育部重点实验室;
【基金】：国家自然科学基金重点项目(编号:U1361207);国家自然科学基金面上项目(编号:41530314)联合资助
【分类号】：P618.13

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