摘要
Seismic wave velocity is one of the most important processing parameters of seismic data,which also determines the accuracy of imaging.The conventional method of velocity analysis involves scanning through a series of equal intervals of velocity,producing the velocity spectrum by superposing energy or similarity coefficients.In this method,however,the sensitivity of the semblance spectrum to change of velocity is weak,so the resolution is poor.In this paper,to solve the above deficiencies of conventional velocity analysis,a method for obtaining a high-resolution velocity spectrum based on weighted similarity is proposed.By introducing two weighting functions,the resolution of the similarity spectrum in time and velocity is improved.Numerical examples and real seismic data indicate that the proposed method provides a velocity spectrum with higher resolution than conventional methods and can separate cross reflectors which are aliased in conventional semblance spectrums;at the same time,the method shows good noise-resistibility.
地震波速度作为地震资料最重要处理参数之一,其准确与否决定了成像精度的高低,也是储层预测和储层反演的基础。常规速度分析方法基于相似系数理论,给定一系列相等间隔的速度进行扫描,以叠加能量或相似系数作为准则进行速度谱制作,但相似谱对速度变化敏感度相对较低,因此分辨率较差。本文针对常规速度谱求取方法的缺陷,提出了一种基于加权相似系数的高分辨率速度谱求取方法,以常规相似系数法为基础,通过引入两个加权函数,提高相似谱在时间和速度方向的分辨率,以确保获得高分辨率的速度谱。利用正演地震记录,证实了该方法获取的速度谱具有比常规方法更高的分辨率,可有效地将混叠在相似谱中的交叉反射区分开,可识别强反射界面附近的弱反射信息,而且具有很好的抗噪能力;同时,通过野外实际数据的测试,证明了该方法对实际资料的适应性。
基金
funded by the National Key Research and Development Plan (No. 2017YFB0202905)
China Petroleum Corporation Technology Management Department “Deep-ultra-deep weak signal enhancement technology based on seismic physical simulation experiments”(No. 2017-5307073-000008-01)。
