CO2集中力源的地震波场特征及应用

CO₂震源通过调节泄压头的出气口控制激发方向,实现集中力源的定向激发,克服了传统震源激发方向不可控的难题,然而CO₂集中力源在煤层中激发的三维波场特征尚未揭示。基于此,笔者通过三维数值模拟、物理分析、现场试验对CO₂集中力源进行研究,结果表明:不同集中力源在煤层中激发的地震波场差异显著,通过力学机制分析了均匀模型及煤-岩-煤模型X方向集中力源下多分量不同方向纵波、横波及槽波振幅差异特性,研究了煤层界面对地震波传播的影响机制,进一步解释了煤层内部激发X方向集中力源加载下体波、槽波的波场特征和传播机理。研究发现X方向集中力源在X分量中沿着震源位置的Y方向槽波振幅最强,Y方向集中力源在Y分量中沿着震源位置的X方向槽波振幅最强,Z方向集中力源的Z分量槽波振幅强。因此,X方向集中力源适合回采工作面Love型槽波透射探测,Y方向集中力源适合掘进工作面Love型槽波超前探测,Z方向集中力源适合Rayleigh型槽波勘探。利用X方向集中力源进行了面内透射试验,对多组CO₂集中力源激发多道接收的地震记录进行了槽波能量衰减成像,探钻对比结果验证了CO₂集中力源地震成像结果的可靠性。下一步重点围绕CO₂震源多类型激发条件下的多波多分量地震波场特征开展研究。

Seismic wave field characteristics and application of CO2concentrated force source

The excitation direction of CO₂source 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 CO₂source concentrated force source in coal seam have not been revealed.This paper studied the CO₂concentrated 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 CO₂concentrated force sources,and the reliability of the seismic imaging results of CO₂concentrated 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 CO₂source.