Feasibility study of nature source in-Seam exploration

The conventional explosive seismic sources are very tightly controlled in high-gas mine, and a novel non-explosive channel wave method is urgently needed as an alternative. Therefore through the theoretical analysis and numerical simulation experiments, we demostrated that the coal seam satisfied the geophysical conditions to develop the nature source in-seam wave. The time-domain numerical simulation experiment of the passive source channel wave was successfully realized by constructing the nature source in-seam wave model with three stochastic terms, including the stochastic spatial position, stochastic initial excitation time and stochastic amplitude of seismic source. We performed frequency dispersion spectrum calculation on the numerical simulation data of nature source in-seam wave using the phase shift method, and the result shows the obvious frequency dispersion characteristics. Moreover, the numerical simulation results demonstrate the existence of nature source in-seam wave in theoretical models, and the development of both fundamental and higher order morphology. Specifically, a field experiment was conducted in the working face of a coal mine in Huainan, Anhui, to successfully collect the data of three components of the nature source in-seam wave, and frequency dispersion spectrum of the measured data was calculated. The calculation results indicate that the three components have the characteristics of frequency dispersion amony which the energy ridge of the frequency dispersion curve of X component is relatively clear. In general, the numerical simulation results show that the geophysical foundation and mechanism of development of nature source in-seam wave is correct. Moreover, the field experimental results confirm the natural existence of nature source in-seam wave in the coal seam, and this method has the feasibility and potential for mine geological exploration.