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由于深反射地震数据具有信噪比低和记录长度长等特点，叠前深度偏移方法的应用有许多困难．为此，我们研究了一种适合于深反射地震的叠前深度偏移方法；包括：用逆风有限差分方法计算程函方程；在常规速度扫描的基础上，用协方差控制提高速度分析精度；用联合反演算法计算层速度，再插值后得到初始速度模型；用Ｋｉｒｃｈｈｏｆｆ法作为偏移速度分析工具，求得最终的速度模型；最终的速度模型作为有限差分深度偏移的输入，求得最终的偏移结果．用该方法对“中国大陆科学深钻工程”东海二维深反射地震数据ＤＨ－４线进行了叠前深度偏移，取得了良好的效果。
Because of the characteristics of low signal-to-noise ratio and long recording length, deep-reflection seismic data have many difficulties in the application of prestack depth migration method. For this reason, we study a prestack depth migration method suitable for deep reflection seismic; including: using the finite difference windward method to calculate the equation of the equation; using the covariance control to improve the accuracy of velocity analysis based on the conventional velocity scanning; The joint velocities are calculated by the joint inversion algorithm, and then the initial velocity model is obtained after interpolation. The Kirchhoff method is used as the migration velocity analysis tool to obtain the final velocity model. The final velocity model is used as the input of the finite difference depth migration to obtain the final Offset results. Using this method, the depth of prestack depth migration of the 2D deep seismic reflection data DH-4 in the “Deep Science Drilling Project” in the East China Sea has been carried out and achieved good results.