基于自然伽马测井的煤系关键金属精细勘探技术  

Fine exploration technology of critical metals ore beds in coal measures based on natural gamma-ray logging

作　　者：边晓 王雷 王喜军 杨敏芳[4] 叶攀 祖淯文 索金玲 邵龙义[1] 鲁静[1] BIAN Xiao;WANG Lei;WANG Xijun;YANG Minfang;YE Pan;ZU Yuwen;SUO Jinling;SHAO Longyi;LU Jing(State Key Laboratory for Exploration and Intelligent Development of Coal Resources,College of Geoscience and Surveying Engineering,China University of Mining and Technology,Beijing 100083,China;PetroChina Coalbed Methane Company Limited,Beijing 100028,China;Management Center of National Nature Reserve of Geological Relics in Liujiang Basin,Qinhuangdao,Hebei 066000,China;Petroleum Exploration and Development Research Institute,PetroChina,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)煤炭精细勘探与智能开发全国重点实验室,中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [2]中石油煤层气有限责任公司,北京100028 [3]河北柳江盆地地质遗迹国家级自然保护区管理中心,河北秦皇岛066000 [4]中国石油勘探开发研究院,北京100083

出　　处：《地质学报》2024年第8期2531-2540,共10页Acta Geologica Sinica

基　　金：国家重点研发计划项目(编号2021YFC2902004);国家自然科学基金面上项目(编号41772161,41472131)联合资助的成果。

摘　　要：滇东—黔西上二叠统煤系底部赋存着累积厚度达数米、以自然伽马测井正异常为特征的Nb-Zr-REY-Ga型关键金属矿层,是我国最有开发潜力的煤系关键金属资源之一。当前对该矿层的研究主要聚焦于关键金属物质来源、赋存状态和成矿模式等方面,而利用自然伽马测井数据对该矿层进行定量识别和浓度计算等工作还未开展过,尽管这项工作对将来这些矿层关键金属的勘探和开发具有重要意义。论文以Zr和Ga两种元素为例,利用收集和实测的关键金属浓度及其对应的自然伽马值等数据,进行了基于自然伽马测井的关键金属矿层精细勘探技术研究。结果表明:研究区Zr和Ga元素浓度的预测模型分别为y=133.42x^(2)+262.23x+224.43和y=31.587e^(0.2273x),指示两者最低开发利用浓度(2000μg/g和50μg/g)对应的自然伽马值分别为2.8 pA/kg和2.0 pA/kg。发现Haar小波3层分解获得的预测矿层位置与地球化学实测的矿层位置吻合度最高。预测模型验证结果表明,Zr和Ga元素浓度预测平均相对误差分别为14.21%和10.97%,矿层厚度预测平均相对误差分别为4.16%和4.82%,说明论文建立的关键金属精细勘探技术可以精确识别研究区关键金属矿层浓度和厚度,对滇东—黔西地区Nb-Zr-REY-Ga型关键金属矿层的精细勘探具有较好的应用价值。The critical metals ore bed,characterized by its enrichment in Nb,Zr,REY,and Ga,is situated at the bottom of the Upper Permian coal measures in eastern Yunnan-western Guizhou,China.This ore bed,with a consistent thickness of several meters and a distinctive positive anomaly in natural gamma-ray data,represents a significant potential resource of critical metals.Previous research on these ore beds mainly focuses on the sources of ore-forming materials,critical metal hosts,and metallogenic models.However,the identification and quantitative calculation of critical metal concentration in these ore beds using logging data remains unexplored,despite the crucial role this analysis plays in guiding future exploration and development of critical metals.Focusing on Zr and Ga as representative elements,we developed concentration prediction models using comprehensive datasets comprising critical metal concentrations and corresponding natural gamma-ray values.The models for Zr and Ga are represented by the equations:y=133.42x^(2)+262.23x+224.43 for Zr and y=31.587^(e0.2273x)for Ga.These models were then utilized to determine the natural gamma-ray values corresponding to the minimum exploitation concentrations of 2000μg/g for Zr and 50μg/g for Ga,yielding values of 2.8 pA/kg and 2.0 pA/kg,respectively.The predicted boundary of the ore bed,obtained through a 3-order decomposition of the Haar wavelet,exhibits a strong correlation with the geochemically determined boundary.Validation of these models demonstrates their efficacy in predicting critical metal concentrations and ore bed thickness.Average relative errors in concentration prediction were found to be 14.21%for Zr and 10.97%for Ga.Similarly,average relative errors in ore bed thickness prediction for Zr and Ga were 4.16%and 4.82%,respectively.These findings underscore the accuracy and potential of this fine exploration technology in accurately predicting critical metal concentrations and ore bed thickness,thereby offering significant promise for future exploration and de

关 键 词：滇东—黔西地区 煤系关键金属 上二叠统煤系 自然伽马测井 小波变换 

分 类 号：P631.81[天文地球—地质矿产勘探] P612[天文地球—地质学]