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本文基于层状介质模型比较了地面激发深部接收信号与深部激发地表接收信号的差异,研究表明地震信号从高速层或者低速层入射时,当入射角不同时都会存在透射系数绝对值大于1的情况;法向入射时,上方入射和下方入射的透射波的振幅传递系数的绝对值不相等;相对于浅层炮点的情况,炮点位于深层时接收到的VSP记录信号更强记录更清晰;微地震事件井中和地表监测的信噪比依赖于许多因素,如几何扩散、衰减效应、噪声水平、信号频率、接收器数目、近地表放大效应以及阻抗对比效应等,本文只考虑井中检波器阵列与微地震震源之间距离的影响,随着距离的增大地面阵列的叠加信号信噪比相对于VSP记录会有明显的提高;阻抗差异和自由表面边界情况会导致入射P波的强度增强,这种效果能够补偿表面增加的噪声造成的影响,使得我们可以在地表通过相对较少的检波器监测微地震信号.
Based on the layered medium model, the difference between the ground-excited deep receiving signal and the deep-excited ground-surface receiving signal is compared. The results show that the absolute value of the transmission coefficient is larger than 1 when the incident angle is different from the high-speed or low-velocity ground ; The absolute values of the amplitude transfer coefficients of the transmitted waves incident on the top and the bottom under the normal incidence are not equal; the VSP recorded signals received by the shots are stronger and clearer than the shallow shots; Microseismic events The signal-to-noise ratio of wells and surface monitoring depend on many factors such as geometric diffusion, attenuation effect, noise level, signal frequency, number of receivers, near-surface magnification effect and impedance contrast effect. In this paper, And the distance between microseismic sources, the signal-to-noise ratio of the superimposed signal of the ground array increases obviously with respect to the VSP recording as the distance increases. The impedance difference and the free surface boundary condition cause the intensity of incident P wave to be enhanced, This effect compensates for the effects of increased surface noise so that we can pass the relatively small Micro-wave monitoring seismic signals.