大地电磁测深不同反演方法的应用效果对比--以安徽皖江地区页岩气调查为例  

Comparison of application effect of magnetotelluric sounding using different inversion methods in shale gas investigation in Wanjiang area of Anhui Province

作　　者：王佳龙 张宝松[1] 陈基炜 石刚[1] WANG Jia-long;ZHANG Bao-song;CHEN Ji-wei;SHI Gang(Nanjing Center,China Geological Survey,Nanjing 210016,China)

机构地区：[1]中国地质调查局南京地质调查中心,南京210016

出　　处：《华东地质》2020年第1期79-87,共9页East China Geology

基　　金：中国地质调查局“下扬子地区古生界页岩气基础地质调查(编号:DD20160180)”和“安徽皖江地区1∶5万页岩气地质调查(编号:12120115100801)”项目联合资助.

摘　　要：在安徽皖江地区页岩气地质调查中,开展了大地电磁测深(magnetotelluric sounding, MT)剖面研究,通过对比4种不同反演方法和不同极化模式的反演结果,分析各方法的优缺点。4种反演方法各有特点,不同极化模式也具有不同的反演效果。地质与钻孔资料表明,二维带地形共轭梯度反演TM极化模式的电性特征清晰,迭代收敛效果最佳,与地质资料吻合较好,可成功识别二叠纪泥页岩低阻异常。初步推断了皖江地区断裂空间展布特征及页岩气目标层分布,可为其他类似地区大地电磁测深勘探反演方法的选取提供参考。Magnetotelluric sounding(MT) section investigation was carried out during geological survey for shale gas in Wanjiang area of Anhui Province. Based on inversion results of four different inversion methods and different polarization modes, this study analyzed their advantages and disadvantages. The results show that the four inversion methods have their own characteristics and different polarization modes also have different inversion effects. Geological and drilling data also shows that 2 D conjugate gradient inversion in TM mode inversions present distinct electrical characteristics and best effect of iterative convergence. Their coupling well with geological data can successfully identify low resistivity anomaly of Permian shale. Therefore, this study preliminarily infers the spatial distribution characteristics of faults and the target strata of shale gas in Wanjiang area, which will provide thinking way for selecting inversion methods of MT exploration in other similar areas.

关 键 词：页岩气调查 大地电磁测深 反演效果 二叠系 安徽皖江地区 

分 类 号：P618.13[天文地球—矿床学] P631.325[天文地球—地质学]