基于一阶差分的岩溶管道充电法电位水平梯度异常分离方法  

An anomaly separation method for horizontal potential gradients of karst channels in mise a la masse based on first order differential

作　　者：陈贻祥[1] 韩凯[1] 甘伏平[1] 潘科[2] 陈玉玲[1] 郑智杰[1] 张伟[1] 杨初长[1] 

机构地区：[1]中国地质科学院岩溶地质研究所/国土资源部、广西壮族自治区岩溶动力学重点实验室,桂林541004 [2]中国建筑材料工业地质勘查中心广西总队,桂林541002

出　　处：《地球物理学进展》2015年第3期1465-1473,共9页Progress in Geophysics

基　　金：中国地质调查局“水[2013]02-024-004”项目资助

摘　　要：在隐伏岩溶探测中,为实现岩溶管道引起的充电法电位水平梯度局部异常与线性或低缓区域背景场的分离,突出局部微弱异常,本文根据半无限均匀大地中,良导电球体和无限长水平圆柱体充电电位水平梯度及其一次导数剖面曲线分布特征与规律,采用两点平滑法和一阶中心差分法推导出充电电位水平梯度一次导数的近视计算公式,建立了差分滤波函数F xi+1+12()h极小值点与线性或低缓区域背景场特征点的对应关系.在此基础上,提出了线性或低缓区域背景场的线性插值公式和拉格朗日插值公式,以及局部异常与线性或低缓区域背景场划分的作图法和解析法.差分滤波函数F xi+1+12()h对充电法电位水平梯度观测误差、地质噪声具有平滑和低通滤波作用,由此差分滤波函数F xi+1+12()h确定的实测充电法电位水平梯度线性或低缓区域背景场将更为合理,实现了充电法电位水平梯度局部异常与线性或低缓区域背景场的有效分离.利用该局部异常与线性或低缓区域背景场划分方法,实际处理了桂东北越城岭山脉东部岩溶区的洛潭水库实测充电电位水平梯度异常数据,提取了受强大区域背景场掩盖了的岩溶管道产生的微弱异常,突出了岩溶病态水库漏水通道、断裂构造分布等地质信息,为岩溶病态水库的除险加固工程供了有效的处理途径和工程靶区.地质钻探工程和地下水示踪试验均验证了所研发的基于一阶差分的充电法电位水平梯度局部异常与线性或低缓区域背景场分离方法的准确性、有效性和实用性.In order to achieve local anomaly separations of buried karst channels from linear or low variation backgrounds for horizontal potential gradients and highlight local or weak anomalies, according to distribution characteristics of a partial derivative of horizontal potential gradients with respect to independent variable X in Mise a la masse for a conducting sphere or a cylinder with infinite length buried in a semi-infinite homogeneous horizontal earth. By double points smoothing and the first-order center differential. Firstly, derive approximate formulas of first order difference for a partial derivative of horizontal potential gradients with respect to independent variable X. And then establish the correspondence between the minimum point of differential filter function F （x（i＋1）＋1/2h） and characteristics of linear or low variation backgrounds. Finally, derivate linear interpolation and Lagrange formulas of local backgrounds with linear or low variations and propose graphical and analytical methods for separating local anomalies from linear or low variation backgrounds. The differential filter function F （x（i＋1）＋1/2h） has been advantageous to smooth and filter observation errors and geological noise for horizontal potential gradients in Mise a la masse. Therefrom the local backgrounds with linear or low variations calculated from above will be more reasonable and local anomaly separations of buried karst channels from linear or low variation backgrounds for horizontal potential gradients and highlight local or weak anomalies has been achieved effectively in the end. Using this method mentioned in this article to deal with horizontal potential gradients data in Mise a la masse for Luotang karst reservoir located in east of Yuecheng Mountain, Northeast of Guangxi, highlighted clearly geological useful information about karst reservoirleakage channels and faulted structures ete by successfully extracting weak anomalies produced by groundkarst conduits and also affected by high regional b

关 键 词：充电法区域背景场 电位水平梯度异常 一阶差分 电位二次导数 差分滤波函数 岩溶管道 水库岩溶渗漏 

分 类 号：P631[天文地球—地质矿产勘探]