Experimental study on imaging method of TEM pseudo wave-field to detect the effect of underground coal-bed gas hydraulic fracturing

Hydraulic fracturing is a common method for increasing the production of coal-bed gas,the fracturing effect is important,and the transient electromagnetic is an effective method for its detection. In this paper,the authors dis- cussed the theory of transient electromagnetic wave-field transformation,realized the extraction of wave-field character- istics from transient electromagnetic signal,proposed an inversion imaging method of velocity analysis based on the waveform characteristics of pseudo wave-field,calculated the inversion results of a three-dimensional numerical model data,achieved an excellent imaging effect for cracking. At last,the practicability and effective of the imaging method were proved by two actual exploration operations in underground. The conclusions show that the inversion imaging method of TEM pseudo wave-field can solve the problem of coal-bed gas hydraulic fracturing in underground.