手持式X荧光光谱仪在济阳坳陷古近系陆相页岩岩心分析中的应用

中国陆相湖盆沉积相变快,表现出很强的岩石组构和化学组成非均质性。为高效刻画这种非均质性,需要获得高密度地质样品的元素地球化学特征等基础信息。利用X荧光光谱(XRF)分析技术,以济阳坳陷沙三、沙四层段泥页岩系统岩心为主要研究对象,优化手持式X荧光光谱仪岩心测试的实验条件,并选取泥页岩和砂岩典型样品进行方法测试,明确了不同岩性的XRF响应特征。通过对系统岩心高密度XRF测试,实现了高效获取岩心元素组成和岩石学特征的目的。初步应用结果表明,该方法可以有效运用于岩性和岩相划分、岩石矿物组成分布特征分析、泥页岩非均质性表征等方面,并为页岩油赋存机理研究重点样品优选奠定基础。

Application of hand-held X-ray fluorescence spectrometry in the core analysis of Paleogene lacustrine shales in the Jiyang Depression

Lacustrine sedimentary facies vary rapidly in rift basins in China, exhibiting significant heterogeneity in shale fabric and chemical composition. In order to characterize the heterogeneity effectively, the analysis of closely spaced geological samples is required to obtain such data as element geochemistry. We employed the technique of X-ray fluorescence spectral analysis (XRF) to study core samples systematically collected from the mudstone/shale section of the third and fourth members of the Eocene Shahejie Formation in the Jiyang Depression, and optimized the experiment conditions of core testing conducted using a hand-held X-ray fluorescence spectrometer. Subsequently, this method was tested with selected shale and sandstone samples to determine the XRF response of diverse lithologies. Through the closely spaced XRF testing on cores, we determined the element composition and petrologic characteristics of cores. Preliminary applications showed the effectiveness of the technique for determining shale lithology and lithofacies, and thus provided a diagnostic tool for shale heterogeneity characterization.