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波前重现是一种解释散射地震信号的勘探方法,它可以应用于金属矿勘探及石油勘探。这种方法使用一种单频机械振动器作为震源,记录来自隐伏在一定深度的地质特征的散射波和沿地面传播的直达波之间的干涉图。由于干涉面波不能进入深部介质,所以,它不包含有关散射体的任何有用信息,利用波长滤波技术把它滤掉。然后,应用与向下延拓积分等效的重现积分确定在各个深度上的复振幅分布图。利用投射复振幅的量值得出散射体真深度的无偏估计值。以一个点状散射体为实例说明这种技术的主要特点。当点状散射体的深度增加,一直增加到真深度,向下延拓特性曲线的振幅峰值随深度增加而增加,然后随深度增加而迅速下降。因此,直到深度达到真深度,“等效宽度”随深度增加而减小,随后又随深度增加。一个任意形状的散射体的特性曲线,可利用该特性曲线与点状散射体的特性曲线进行褶积求得。
Wavefront reconstruction is a method of interpretation of scattered seismic signals, which can be applied to metal exploration and oil exploration. This method uses a single-frequency mechanical vibrator as the source of vibration, recording the interference pattern between a scattered wave from a geological feature buried at a certain depth and a direct wave propagating along the ground. Since interfering surface waves do not have access to deep media, it does not contain any useful information about the scatterer, filtering it out using wavelength filtering techniques. Then, the reconstructed integral equivalent to the downward continuation integral is applied to determine the complex amplitude distribution at each depth. The unbiased estimate of the true depth of the scatterer is derived from the magnitude of the projected complex amplitude. A point scatterer is used as an example to illustrate the main features of this technique. When the depth of point scatterers increases and reaches the true depth, the peak amplitude of the downward continuation characteristic curve increases with the increase of depth and then decreases rapidly with the increase of depth. Therefore, until the depth reaches true depth, “equivalent width ” decreases as depth increases, and then increases with depth. The characteristic curve of an arbitrarily shaped scatterer can be convoluted by using the characteristic curve of the characteristic curve and the point scatterer.