叠前深度偏移的应用范围和几点认识

APPLICABILITY OF PRESTACK DEPTH MIGRATION AND SOME GAINS

讨论了叠前深度偏移解决地质成像的应用范围，从时间偏移和深度偏移的基本概念出发，并给出了两个量板；从水平相对误差和垂直相对误差两方面给出了对何种地质构造的成像需使用深度偏移。深度偏移着重解决倾斜的、速度横向变化的地层以下构造的成像问题。结合了波动理论和射线理论的观点，引入一种基于拉东—高斯射束原理的深度偏移方法，这有助于解决我国陆相沉积构造的成像问题。深度偏移成功的关键是建立精确的地下速度模型，所以在文中还分析了多种速度建模的方法。

How can the method of prestack depth migration solving geological imaging problems? The answer is given by the basic concept of migration in time and depth domain,and two gages are given in this paper.The relative error of horizontal distance and vertical depth are also given by using the methods of migration in time and depth domain,and these can tell us which geological structure the method of depth migration must be used.The method of depth migration is used to solve the imaging of stratigraphy above which there are slant layers and horizontal viable velocity.In the paper,the depth migration method based on Radon transformationGaussian beam principle is introduced.The viewpoints of ray and wave theory are combined in the method which can help us solving the imaging problem of continental deposit stratigraphy.The successful key point of depth migration is the accurate velocity modeling.Therefore,many methods of velocity modeling are analyzed.