矿井掘进工作面富水区多点电源高分辨电法探测

为准确探查矿井掘进工作面富水区空间分布,提出了多点电源高分辨电法探测技术。在掘进工作面后方一次布置多道电极观测系统,从掘进工作面向后1/4测线电极依次作为供电点电源电极,采用单极−偶极装置采集数据,得到的视电阻率值视为多点电源电测深数据。利用多点电源电测深成像结果,快速判别掘进工作面是否存在相对富水区,判断富水区是在掘进工作面前方还是后方;将探测范围划分出一系列目标单元,对多点源电测深数据,采用异常目标匹配滤波处理方法,得到探测范围相关度成像结果,其中高相关度值范围准确地反映了掘进工作面前后富水区的分布位置;利用实测多点电源电测深数据拟合一条理论模板曲线,采用比值法校正得到的多点电源测深比值数据能够有效消除巷道空腔及层状地层等因素的影响。在淮南矿业集团潘三矿掘进工作面探测实例表明,多点电源高分辨电法能够准确探查出掘进工作面富水区的位置,有效指导巷道掘进水害防治工作。

巷道前方地质异常八点电源电法随掘探测响应

为可靠探查掘进巷道前方地质异常体情况,提出了八点电源随掘超前探测方法。从巷道迎头向后沿巷帮中线布置32道电极,电极间距5m。近工作面8个电极顺次做为点电源电极,采集整条测线单极-偶极装置视电阻率值。根据微分电测深探测原理,每个点电源所测得的视电阻率值可视为该点电测深结果,得到电测深曲线图和视电阻率成像图。巷道每掘进20m,将最后4个电极滚动布置到新测线前4个电极,再进行八点电源电测深数据采集,得到连续变化的电测深曲线和电测深成像结果。根据单极-偶极装置视电阻率响应公式计算了工作面超前方向地质异常球体的响应,研究结果表明:对同一地质异常球体,距离掘进工作面由远到近,电阻率响应越来越明显;低阻球体边缘到点电源距离不大于球体半径时,可以探查;高阻球体边缘到点电源距离不大于1/2球体半径时,可以探查;低阻球体的响应强于高阻球体。地质异常体半径越大,能够被探查出的超前距离越大。因此,超前0~50m范围地质异常探测精度高;超前50~100m范围地质异常探测可靠性低,适宜解释是否有较大范围的地质异常区。八点电源电法随掘超前探测能够可靠探测工作面前方地质异常的赋存情况,为工作面安全快速掘进提供地质保障。

高密度电探法在隧道勘察中的应用

我国碳酸盐岩分布极为广泛,由岩溶引起的地质灾害十分严重。快速、准确地查明地下岩溶等不良地质体在空间的赋存位置和形态,是工程地质勘察中要解决的重要课题之一。在庐山环南山一级公路(隘口—仓房)桃花源隧道地质勘察中,采用高密度电探法与钻探相结合,较准确地查明了沿隧道轴线范围内不同岩性的分界面及地下溶洞的分布情况,取得了良好的地质效果,充分显示了该方法在地质勘察中的优势。

用综合电探方法确定断层倾向

坝址位于宁夏境内,属黄河水利工程。目前该工程尚处于可行性研究阶段。据初步勘察,在所选坝线以南约700m存在一近东西走向的高倾角断层F3,其宽度大致为12m,见示意图1。

电探法检测技术控制桥梁桩基施工质量

本文介绍电探法桩基施工质量检测技术方法,其特征在于将一个电极连接到钢筋笼上,另一个电极在钢筋笼的内侧或外侧连续检测两个电极间电介质的电阻或电阻率的变化情况,用于分析桩基的成孔孔径、泥皮厚度、桩底沉渣挂壁、地下潜流、桩身混凝土完整性、混凝土保护层的灌注质量,具有快速、连续、灵敏度高的特点,能检测桩身裂缝的存在。

电探法桩基施工质量监控及加固技术的方法（申请号：03126858．7）

本发明涉及电探法桩基施工质量监控及加固技术的方法，适用于钻（挖）孔桩、地下连续墙、沉管灌注桩、CFG桩等的施工质量监控。其主要特征在于采用电探法来检测清孔质量；监控混凝土灌注施工质量，能准确判断混凝土缺陷的性质、影响程度和产生原因；能在混凝土流态时对缺陷进行加固处理并检测处理效果；

三维电法超前探在巷道掘进水害防治中的应用

超前探测是煤矿开采之前一个必要的环节,该环节的实施能够使开采人员明确煤层顶底板的富水情况,同时还能够明确煤矿围岩的富水情况,进而使开采人员充分了解矿井中断层的构造等相关信息,从而保障煤矿开采的安全性。目前,在使用的矿井超前探测方法中,三维电法超前探测技术是一种常用技术,具有良好的探测预报效果。

探地雷达-电法-化探技术在地下排污管网探测工程中的应用

介绍探地雷达

Electrical structure identification of deep shale gas reservoir in complex structural area using wide field electromagnetic method

To fully exploit the technical advantages of the large-depth and high-precision artificial source electromagnetic method in the complex structure area of southern Sichuan and compensate for the shortcomings of the conventional electromagnetic method in exploration depth,precision,and accuracy,the large-depth and high-precision wide field electromagnetic method is applied to the complex structure test area of the Luochang syncline and Yuhe nose anticline in the southern Sichuan.The advantages of the wide field electromagnetic method in detecting deep,low-resistivity thin layers are demonstrated.First,on the basis of the analysis of physical property data,a geological–geoelectric model is established in the test area,and the wide field electromagnetic method is numerically simulated to analyze and evaluate the response characteristics of deep thin shale gas layers on wide field electromagnetic curves.Second,a wide field electromagnetic test is conducted in the complex structure area of southern Sichuan.After data processing and inversion imaging,apparent resistivity logging data are used for calibration to develop an apparent resistivity interpretation model suitable for the test area.On the basis of the results,the characteristics of the electrical structure change in the shallow longitudinal formation of 6 km are implemented,and the transverse electrical distribution characteristics of the deep shale gas layer are delineated.In the prediction area near the well,the subsequent data verification shows that the apparent resistivity obtained using the inversion of the wide field electromagnetic method is consistent with the trend of apparent resistivity revealed by logging,which proves that this method can effectively identify the weak response characteristics of deep shale gas formations in complex structural areas.This experiment,it is shown shows that the wide field electromagnetic method with a large depth and high precision can effectively characterize the electrical characteristics of deep,low-resistivity thin layers in complex structural areas,and a new set of low-cost evaluation technologies for shale gas target layers based on the wide field electromagnetic method is explored.

Field testing of the surface electromagnetic prospecting system

To test the performance of the Chinese whole-surface electromagnetic prospecting （SEP） system, system integrations, instrument performances, and large-scale production viabilities in Liaoning province and Inner Mongolia were measured via extensive field tests. Resultant electric fields, magnetic fields, apparent resistivities, impedance phases, and inversion profiles compared favorably with results of commercial equipment from other countries. The inversion results agreed well with the geologic information from boreholes. Field tests showed that the SEP system is stable, reliable, lightweight, and easy to operate, making it suitable and ready for real-field exploration.

Singularity-free Green's function for EM sources embedded in a stratified medium

We present a method to unify the calculation of Green＇s functions for an electromagnetic（EM） transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is introduced through the source location.The potentials for Green＇s function are derived by decomposing the partial wave solutions to Helmholtz＇s equations into upward and downward within boundaries.The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level.The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fields at the source interface.Only the initial terms are related to the transmitting sources and thus need to be modified for different transmitters,whereas the kernel connected with the stratified media stays unchanged.Hence,the present method can be easily applied to EM transmitting sources with little modification.The application of the proposed method to the marine controlled-source electromagnetic method（MCSEM） demonstrates its simplicity and flexibility.

Percolation Network Modeling of Electrical Properties of Reservoir Rock*

Based on the percolation network model characterizing reservoir rock＇s pore structure and fluid characteristics, this paper qualitatively studies the effects of pore size, pore shape, pore connectivity, and the amount of micropores on the I - Sw curve using numerical modeling. The effects of formation water salinity on the electrical resistivity of the rock are discussed. Then the relative magnitudes of the different influencing factors are discussed. The effects of the different factors on the I - Sw curve are analyzed by fitting simulation results. The results show that the connectivity of the void spaces and the amount of micropores have a large effect on the I - S, curve, while the other factors have little effect. The formation water salinity has a large effect on the absolute resistivity values. The non-Archie phenomenon is prevalent, which is remarkable in rocks with low permeability.

3D finite element numerical simulation of advanced detection in roadway for DC focus method

Within the roadway advanced detection methods, DC resistivity method has an extensive application because of its simple principle and operation. Numerical simulation of the effect of focusing current on advanced detection was carried out using a three-dimensional finite element method （FEM）, meanwhile the electric-field distribution of the point source and nine-point power source were calculated and analyzed with the same electric charges. The results show that the nine-point power source array has a very good ability to focus, and the DC focus method can be used to predict the aquifer abnormality body precisely. By comparing the FEM modelling results with physical simulation results from soil sink, it is shown that the accuracy of forward simulation meets the requirement and the artificial disturbance from roadway has no impact on the DC focus method.

综合防治水技术在煤矿中的应用与分析

采用物探、钻探联合勘探技术可以提高矿井水文地质预测预报的准确性,为矿井安全生产提供可靠的技术保障。

3D laterolog array sonde design and response simulation

A new three-dimensional laterolog array sonde（3D-LS） is presented. The 3DLS is based on existing high-resolution laterolog array and azimuthal resistivity imaging sondes with radial, longitudinal, and circumferential detection abilities. Six investigation modes are designed using the 3D finite-element method and different investigation depths are simulated based on the pseudo-geometrical factor of the six modes. The invasion profile is described using multi-array radial logs. From the analysis of the pseudo-geometrical factor, the investigation depth of the 3D-LS is about 1.5 m for conductive invasion, which is close to that of the dual laterolog tool but greater than that of the highly integrated azimuthal laterolog sonde. The vertical and azimuthal resolution is also analyzed with the same method. The 3DLS can detect low-resistivity anomalies of 0.5 m thickness and 15？ around the borehole for infinitely thick formations. This study lays the foundation for more work on 3D laterolog array sonde for evaluating low-resistivity anomalies.

Application of the Adaptive Shrinkage Genetic Algorithm in the Feasible Region to TEM Conductive Thin Layer Inversion

Combining the adaptive shrinkage genetic algorithm in the feasible region with the imaging of apparent vertical conductance differential, we have inverted the TEM conductive thin layer. The result of the inversion demonstrates that by adaptive shrinkage in the feasible region, the calculation speed accelerates and the calculation precision improves. To a certain extent, in this method we surmount the transient electromagnetic sounding equivalence and reduced equivalence scope. Comparison of the inverted result with the forward curve clearly shows that we can image the conductive thin layer.

RESEARCH ON DIRECT CURRENT ELECTRIC FIELD CHARACTERISTICS OF OVERBURDEN FAILURE AND ITS APPLICATIONS

The overburden failure causes the changes of the constant electric field, and the resistivity is the main parameter in these changes. The experimental simulation about tbe response relation between the overburden failure and its electrical parameter changes is made by building the similar material physics model of mining. The experiment results are used to analyze and test the in-situ detection. The research indicates that the resistivity changes with the electric characteristic of the rock in cracked zone and caving zone caused by overburden failure, the response characteristics of resistivity vary with the failure degrees at different overburden failure zone and that they are corresponding. The resistivity method used in monitoring the overburden failure can determine the height and the affecting scopes of the cracked zone and caving zone. This can provide reliable techaological guarantee for mining design and safe production.

The application of the high-frequency electromagnetic sounding method in the exploration of underground thermal water

High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic field as a field source. It has higher resolution and greater depth penetration than the direct current method and is especially fit for geothermal energy exploration and low- and mid-level groundwater detection. We introduce a successful application of high-frequency electromagnetic sounding for evaluating geothermal water resources. The high frequency electromagnetic system （MT-USA with a frequency range from 10 KHz to 1 Hz） is first applied to sample field data from China. A remote reference station is used to assure sampled data quality. We then perform 2D inversion image processing with the electrical method data. The results basically indicate the spatial distribution of underground geothermal water and provide favorable clues to finding the sources of the subsurface geothermal water in this area.

The Application of High-density Resistivity Method to the Evaluation on the Stability of Gongchangling Open Pit＇s Slope

High-density resistivity method is a new, efficient electrical prospecting method, which can complete a two-dimensional （vertical and horizontal） prospecting process, possesses certain imaging functions for the geo-electric structure, and integrates electric profiling method with electric sounding method together. In this paper, the basic principle, data processing, and result explanation and inference of high- density resistivity method are introduced by taking the application of high-density resistivity method to the prospecting project in the slope of Gongchangling Open Pit, Liaoyang. The result of the prospecting result map analysis showed that the prospecting result was basically in line with the actual situation and proved the great significance of high-density resistivity method to the evaluation on the slope stability of Gongchangling open pit.

Electrode Design of Cylindrical Coplanar-grid CdZnTe Detector by Finite Element Methods

Cylindrical coplanar-grid configurations,which offer a lot of advantages over established designs,can effectively overcome the problem of poor hole collection.Finite element analysis is utilized for simulating the potential distribution of the cylindrical coplanar-grid detector under different models by varying the widths of grid and pitch of electrodes. In addition, a modified grid pattern has been discussed to improve the weighting potential match between two grids. In this way, the geometry of electrodes for cylindrical coplanar-grid detectors is optimized.