摘要
本文采用一个具有4个待定参数的函数去逼近震源子波,利用黏弹介质中单程波传播理论推导出了地震子波包络峰值处瞬时频率(EPIF)和品质因子之间的解析关系;同时,为提高瞬时频率的估计精度和抗噪性能,在小波域中发展了一种计算瞬时频率的方法,并在此基础上提出了估算VSP资料Q值的方法,简称小波域包络峰值处瞬时频率法(WEPIF).合成的VSP数据衰减估计结果表明,与对数谱比法和中心频率偏移法相比较,WEPIF法受到界面反射波影响相对较小、计算结果稳定、精度相对较高.将WEPIF法用于某气田的单炮零偏6级VSP资料Q值估计,结果表明,吸收强弱与储层含气性高低有良好的对应关系.
In the work, employing a function with four undetermined parameters to model the source wavelet, an analytical relation between Q-factor and envelope peak instantaneous frequency （EPIF） is derived from the theory of one-way waves propagating in an anelastic medium; at the same time, a method for extracting instantaneous frequency （IF） in wavelet domain is developed for improving the precision and anti-noise performance of IF estimation, and based on these, a method called EPIF in wavelet domain （WEPIF） is proposed for estimating Q- factor of VSP data. Test of synthetic zero-offset VSP data indicates that, comparing with logarithm spectral ratio method and centroid frequency shift method, WEPIF method is more stable and precise, and less sensitive to interface reflection waves. The Q-factors of single-shot zero-offset VSP data of 6-series from a certain gas field is estimated by WEPIF method, and the result shows that the extent of absorption corresponds well to the gas saturation of reservoirs.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第3期853-861,共9页
Chinese Journal of Geophysics
基金
国家863计划项目(2006AA09A102)
国家自然科学基金重点项目(41070424)资助
关键词
衰减
品质因子
瞬时频率
小波变换
包络峰值处瞬时频率
Attenuation, Quality-factor, Instantaneous frequency （IF）, Wavelet transform, Envelope peak instantaneous frequency （EPIF）
作者简介
高静怀，男，1960年生，教授，博士生导师，1997年获西安交通大学博士学位．主要从事复杂介质中地震波传播与成像及地震资料处理的理论与方法等研究．E-mail：jhgao@mail．xjtu．edu．cn
