The Research of Borehole-Ground DC Method Detecting Anomaly of Underground Dynamic High-Resistivity Conductor and Case Hole Effect

In exploration of coalbed methane, the release and accumulation of absorbed gas driven by underground water is equal to existence of high-resistivity conductor. Application of numerical modeling conducted with finite difference to analyze anomaly sounding corresponding to underground high-resistivity conductor in borehole-ground DC method, and research of casing effect for DC method combining with physical modeling, may attribute to development of borehole-ground DC method which is capable for exploration of coalbed methane.