Seismic wave field characteristics and application of CO2 concentrated force source

The excitation direction of CO2 source is controlled by adjusting the outlet of the pressure relief head to realize the directional excitation of concentrated force source,which overcomes the problem that the excitation direction of the traditional source is not controllable.However,the three dimensional wave field characteristics of CO2 source concentrated force source in coal seam have not been revealed.This paper studied the CO2 concentrated force source by three dimensional numerical simulation,physical analysis and field test.The results show that the seismic wave field excited by different concentrated force sources in coal seam is significantly different.The amplitude difference characteristics of multi component P waves,S waves and channel waves in different directions under X direction concentrated force source of uniform model and coal rock coal model were mechanically analyzed,the influence mechanism of coal seam interface on seismic wave propagation was studied,and the wave field characteristics and propagation mechanism of body waves and channel waves excited by X direction concentrated force source in coal seam were further explained.The results show that the amplitude of channel waves excited in the X direction concentrated force source along the Y direction of source position is the strongest in X component,and the amplitude of channel wave excited in the Y direction concentrated force source along the X direction of source position is the strongest in Y component,and the Z direction concentrated source has strong amplitude in Z component channel wave.The X direction concentrated force source is suitable for the Love channel wave transmission detection of the working face,the Y direction concentrated force source is suitable for the Love channel waves advanced detection in the heading face,and the Z direction concentrated force source is suitable for Rayleigh channel wave detection.Transmission test in working face was carried out by using X direction concentrated force source.The channel wave energy attenuation imaging was performed on the seismic records excited by multiple of CO2 concentrated force sources,and the reliability of the seismic imaging results of CO2 concentrated force sources was verified by the comparison results of detection and drilling.The next step focuses on the characteristics of multi wave and multi component seismic wave field under the multi type excitation of CO2 source.