高斯射线束叠前深度偏移成像研究

Gaussian beam prestack depth migration

高斯束偏移方法弥补了克希霍夫偏移方法在处理多值走时及焦散问题方面的不足,同时突破了单程波偏移算子的倾角限制。系统介绍了高斯束偏移方法的基本原理,应用理论模型验证了高斯束偏移方法在陡倾角构造成像能力上优于二阶广义屏算子这一结论。由于高斯束中心射线携带了丰富信息,在偏移算法中给出了直接计算角度域共成像点道集的方法。实际数据测试结果表明,在复杂构造、陡倾角以及低信噪比资料成像方面,高斯束偏移成像效果明显好于目前常用的克希霍夫偏移成像方法。

Gaussian beam migration can complement the deficiencies of Kirchhoff migration including multi-values traveltime and caustics.Meanwhile,it breaks the dip limitation of one-way wave migration operator.In this paper,the principles of Gaussian migration was systematically introduces.Then,the theoretical model testing verified that Gaussian beam migration can better imaging the high-dip structures than second-order generalized screen operator.Since Gaussian bean central ray carries abundant information,the method for directly computing angle-domain CIP gathers was introduced in migration algorithm.Actual data testing indicated that Gaussian beam migration has better imaging results than Kirchhoff migration for complex structures,high-dip structures and low S/N data.