基于CSAMT电场分量的电性标志层深度校正技术及应用

Depth correction technique of electrical marker based on electrical field component of CSAMT

可控源音频大地电磁(CSAMT)是探测含煤地层富水区及采空区的重要地球物理方法,但其探测深度误差比较大,采用电性标志层进行深度校正,达到精确解释地层的目的。首先,提出基于电场单分量视电阻率计算方法,只需通过平移即可获得全区视电阻率,无需迭代,简单快速。接着,分析视电阻率微分极值与电性标志层的关系,通过测井电阻率曲线识别出电性标志层,然后通过比值计算深度校正系数,在全区进行插值得到任意测点的校正深度。对新元煤矿31004工作面R280测线数据进行深度校正处理,结果表明:校正后的深度和实际地层基本吻合。最后,通过已知充水采空区边界、淋水点以及钻孔揭示的结果进行对比验证,达到了预期效果。该方法为CSAMT在含煤地层进行精细化数据处理和解释提供了新的思路。

Controlled Source audio-frequency Magnetotellurics(CSAMT)is an important geophysical method to detect water-rich areas and goafs in coal strata.However,the detection depth error is relatively large.Therefore,the electrical marker layer is used for depth correction to achieve the purpose of accurate interpretation of strata in this paper.A method for calculating all time apparent resistivity based on single component of electric field is proposed.The apparent resistivity can be obtained by translation algorithm,which is simple and fast without iteration.The relationship between the differential extremum of the apparent resistivity and the electrical marker layer is analyzed,and the electrical marker layer is identified by the well logging resistivity curve,then the depth correction coefficient is calculated by the ratio.Finally,the correction depth of any measuring point is obtained by interpolation in the whole region.Depth correction is carried out for the survey line R280 data of working face 31004,Xinyuan Coal Mine,and the results show that the corrected depth is in better agreement with the actual formation.Through comparison and verification of the known of known water-filled goaf boundary,water spraying point and borehole data,the desired goals are achieved.This method provides a new idea for fine data processing and interpretation by CSAMT in coal strata.