基于时窗种子提取的海洋地震资料侧面噪声压制方法

受过往船只噪声和平台等障碍物侧反射的影响,导致海洋地震勘探资料中存在侧面反射噪声,该类噪声具有非线性和宽频带的特征,常规方法对其难以有效衰减。为此,分析了侧反射和大船干扰两种主要侧面噪声的形成机理,提出了一种基于时窗种子提取的侧面噪声压制方法。通过对含侧面噪声的种子炮提取障碍物反射源或侧面噪声源的坐标值,自动控制噪声形态;再通过噪声时窗优化,实现了f-k域无假频滤波衰减侧面噪声。含模拟侧面噪声单炮记录的测试和实际含侧面噪声三维地震数据的试处理结果表明,该方法能有效压制侧面噪声并保护有效信号,在海洋地震资料处理中具有实际的应用价值。

深水多次波与噪音同时压制技术

海洋地震资料预处理,两大难题就是噪音和多次波。常规的近道多次波压制有预测反褶积和SRME,中远道多次波压制有速度滤波等方法。然而在深水崎岖海底资料中,对于侧面反射、绕射多次波等等,常规的多次波压制方法往往失效,原因在于常规的多次波压制方法的理论多假设地震波是以二维双曲线方式传播,实际上地下地震波传播路径复杂,常规去多次方法有局限。另外对于噪音的压制,技术人员往往是头痛医头脚痛医脚,对不同的噪音采用不同的模块进行压制,即增加了处理步骤,也增加了损伤有效波的风险。本文研究了一种利用剔除拟合法并结合LIFT思想进行深水多次波和噪音压制技术,一次处理流程可以同时压制多种噪音和多种多次波,取得了良好的效果。

海上地震勘探常见干扰波

在长期的海上地震勘探实践中，收集了丰富的具有‘海上特点’的干扰波资料，通过分析，整理将其划分为六大类二十种类型。分别阐述了各种干扰波产生的原因、在记录上的表面特征，以及在施工现场的一般处理方法。

A Free Surface Frequency Domain Green Function with Viscous Dissipation and Partial Reflections from Side Walls

The free-surface Green function method is widely used in solving the radiation or diffraction problems caused by a ship or ocean structure oscillating on the waves. In the context of inviscid potential flow, hydrodynamic problems such as multi-body interaction and tank side wall effect cannot be properly dealt with based on the traditional free-surface frequency domain Green function method, in which the water viscosity is omitted and the energy dissipation effect is absent. In this paper, an open-sea Green function with viscous dissipation was presented within the theory ofvisco-potential flow. Then the tank Green function with a partial reflection from the side walls in wave tanks was formulated as a formal sum of open-sea Green functions representing the infinite images between two parallel side walls of the source in the tank. The new far-field characteristics of the tank Green function is vitally important fur improving the validity of side-wall effects evaluation, which can be used in supervising the tank model tests.