Supercritical CO2 source for underground seismic exploration

Abstract

Underground seismic exploration is a technical assurance for the geological transparency of the mining face. However, seismic exploration with explosive seismic source has shortcomings such as acquisition difficulties and serious safety hazards. Besides, dynamic detection of the mining face with explosive source is challenging. To this end, the study proposes a supercritical CO2 source based on the underground seismic geological condition of the roadway. The phase change blasting mechanism of the supercritical source was revealed, and the equivalent energy of the source was calculated. Additionally, a field test was also carried out. The results show that the seismic signals of the CO2 source have clear P-waves, S-waves, and channel waves; the signal excited by the source has strong energy and rich frequency bands; the signal-to-noise ratio of single CO2 source is high; and the attenuation images of transmitted channel wave excited by the source shows high resolution and the result is consistent with field validation data. CO2 source can be used as a new source of underground in-seam seismic exploration and it also helps in reducing the dependence of explosive seismic source. Besides, the study can achieve early warnings of dynamic geological disasters in the working face and has the advantages of high efficiency, safe, low cost, and environmentally friendly. Keywords: Seismic exploration, Seismic source, CO2 source, Spectrum, Transmitted channel wave