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为了提高山地、沙漠、戈壁、黄土塬地区地震数据处理的效果,解决这些地区地表起伏变化对反射波地震波场的影响问题,提出将(x-z)域的曲网格映射成(ξ-η)域中的矩形网格的方法,推导出(ξ-η)域中的二维标量声波方程,并根据推导出来的波动方程采用逆时法将起伏地表上的地震波场在(ξ-η)域中向下延拓至一个水平面,从而校正地表起伏对地震波传播时间的影响.结果表明:对模型地震波场进行延拓计算,延拓前起伏表面上炮点位置处第1层的反射波旅行时间与延拓到平面上后该位置处第1层反射波的旅行时间差为59 ms,理论公式计算出的二者之差为61 ms,理论计算与实际延拓的结果相一致.在已知地表速度结构的前提下,该方法能够校正由于地表起伏变化对地震反射波造成的旅行时间的影响.
In order to improve the effect of seismic data processing in mountain, desert, Gobi and Loess Plateau, and to solve the problem of the influence of surface undulation on the seismic wavefield of reflected waves in these areas, the paper proposes that the (xz) Dimensional scalar sound wave equation in the (ξ-η) domain is deduced and the seismic wave field on the fluctuating surface in the (ξ-η) domain is obtained by the inverse time method according to the deduced wave equation And then extend to a horizontal plane to correct the influence of surface undulation on seismic wave propagation time.The results show that the traveltime of the reflected wave at the first layer on the surface of the antecedent undulating surface extends to The travel time difference of the first layer reflected wave at this position after extended to the plane is 59 ms, and the difference between the two calculated by the theoretical formula is 61 ms. The theoretical calculation is consistent with the actual extension results. Structure, this method can correct the influence of the fluctuation of the surface on the travel time caused by the seismic reflection wave.