局域双曲线Radon变换压制散射波研究与应用

Suppressing Method Study and Application of Seismic Scattered Wave Based on Local Hyperbolic Radon Transform

一般而言,由于地下非均质体的存在所产生的二次波源,由它再生成新的波场,叫散射波场。目前,将散射波作为有效波来成像,已开始在溶洞和裂缝等特殊地质体的识别中得到应用。但对于野外资料采集来说,地表复杂地区,如戈壁、砾石区和山前带,大量存在的散射波却是干扰波,它们的存在会严重影响资料的品质,而其研究与实际应用国内外还很少。因此,通过正演模拟,分析散射波的基本特征,在此基础上研究散射波的去噪方法显得十分必要。本文从地震波运动学时距关系出发,研究了反射波和散射波的几何特征;然后用有限差分正演,模拟了散射波场,用理论模型研究并测试了局域双曲线Radon变换散射波去噪新方法。对于实际炮集资料,分析了F-K滤波方法压制散射噪声的局限,采用局域双曲Radon变换有效地去除了炮集中存在的散射噪声,取得了较好的应用效果。

Generally, seismic waves scatter when they meet a subsurface heterogeneous body, i.e. a scattering source. Currently, scattered imaging technique which uses scattered waves as effective waves has been used in the identification of special geologic bodies such as caves and fractures. However, in the Gobi Desert, gravel areas, mountain front and other surface complex areas, scattered waves affect the quality of seismic data seriously and are interference waves for seismic field data. Because related research and practical application are not clearly seen at home and abroad, it is necessary to analyze basic characteristics and study denoising method of scattered wave. Firstly, this paper analyzes the geometric characterization of reflection wave and scattered wave based on the t-x relationship in seismic kinematics. Then, finite difference method is applied to simulate scattered wave field and local hyperbolic Radon transform method is proposed to suppress scattered wave for theoretical models. For field CSP data, the limitation of FK filtering to denoise scattered wave is analyzed and then local hyperbolic Radon transform technology is used to remove scattered wave on shot gathers, the results show that scattered wave obtains effective suppression using this method.