基于激光诱导击穿光谱的页岩与砂岩多元素定量分析  

Multi-Element Quantitative Analysis of Shale and Sandstone Based onLaser Induced Breakdown Spectroscopy

作　　者：时铭鑫 吴坚[1] 吴迪 李京徽 邱岩 郭歆宇 周颖 宋自远 陈民鑫 Shi Mingxin;Wu Jian;Wu Di;Li Jinghui;Qiu Yan;Guo Xinyu;Zhou Ying;Song Ziyuan;Chen Minxin(State Key Laboratory of Electrical Insulation and Power Equipment,School of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China;Ministry of Education Key Laboratory of Electronic Physics and Devices,School of Electronic Science and Engineering,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China)

机构地区：[1]西安交通大学电气工程学院,电气绝缘与电力设备国家重点实验室,陕西西安710049 [2]西安交通大学电子科学与工程学院,电子物理与器件教育部重点实验室,陕西西安710049

出　　处：《中国激光》2024年第8期244-252,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划青年科学家项目(SQ2021YFB3703200);中核集团青年英才项目;国家自然科学基金(62205266);中国博士后科学基金(2022M2514)。

摘　　要：面向天然页岩与砂岩矿物元素组分快速定量分析的检测需求,笔者搭建了具有自动化分析功能的显微分析激光诱导击穿光谱系统,并采用该系统对油气页岩与砂岩天然岩石样本进行了快速检测。分析了砂岩与页岩光谱的不确定度差异,形成了流程化的包括光谱数据提取、筛选、校正、归一化的预处理方法,有效降低了单一样本与样本间光谱不确定度。基于偏最小二乘回归,形成了模型输入参数优化流程,避免了模型过拟合与欠拟合,提高了定量预测准确度。对岩石中的Si、Ca、Fe、Al、Mg等元素进行了定量分析,多数样本的平均预测均方根误差小于1%。本研究为天然岩石的矿物组分分析与岩性识别提供了技术支持。Objective Shale oil is an important unconventional resource that has become a major development focus.Owing to the possible reserves of petroleum and natural gas,information from core samples,which mainly contain geochemical and mineralogical information,has attracted increasing attention from geologists and energy enterprises.Conventional analytical methods for mineralogical analysis,including inductively coupled plasma optical emission or mass spectrometry(ICP-OES/MS),instrumental neutron activation analysis(INNA),and X-ray fluorescence(XRF),are unsuitable for the in-situ analysis of shale because of their slow analysis speed and limited detection range.Laser-induced breakdown spectroscopy(LIBS)is a novel analytical method for various materials that uses laser pulses focused on a sample to generate laser-produced plasma and spectral emissions.With the advantages of minimal sample preparation,remote analysis,microsample ablation,and high analytical speed,LIBS is an optional access method for analysis of cores.In this study,multi-element quantitative analysis of natural shale and sandstone samples is conducted using a micro-LIBS system.A standardized spectral preprocessing method is developed to reduce spectral uncertainty,and a model input parameter optimization process is established to prevent model overfitting while improving model prediction accuracy.A quantitative analysis of Si,Ca,Fe,Al,Mg,and other elements in the shales and sandstones is performed,and the average predicted root-mean-square error of most samples is less than 1%,providing technical support for regular mineral component analysis and lithology identification of shales and sandstones.Methods A micro-LIBS system was established in this study,consisting of a laser,spectrometer,timing synchronizer,computer,and optical microscope.The system used a nanosecond-pulse laser to generate a laser beam that passes through a laser beam splitter and was sampled by a photodiode to detect the laser timing.The transmitted laser beam was introduced into an opt

关 键 词：光谱学 激光诱导击穿光谱 页岩 砂岩 光谱预处理 元素定量分析 

分 类 号：O436[机械工程—光学工程]