Application of the borehole-to surface electric potential image technique to monitoring hydraulic fractures of coalbed methane

The borehole-to surface electric measurement image technique is applicated in the monitoring hydraulic fractures of coalbed methane in Beipiao Coal Mine.The distribution of the electric potential is measured before and after the injection of the high mineral conduct electricity liquid,the distribution of specific resistance in the injective layer is calculated after the dealing with the data and inversion calculation,thus the pattern of hydraulic fracture is pointed out.The applicability of this technique to formation is discussed.