基于波干涉原理的套管井阵列声波处理方法及其应用  

An interference-based array signal processing technique for cased-hole acoustic logging and applications

作　　者：唐晓明 祁晓 张博 李盛清 苏远大[1] 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,COSL-UPC声学测井联合实验室,青岛266580

出　　处：《地球物理学报》2015年第4期1447-1457,共11页Chinese Journal of Geophysics

基　　金：国家重点基础研究发展计划(2014CB239006)资助

摘　　要：在套管井测井中,沿着钢管产生的拉伸波(即管波)在声波数据中产生很强的干扰,使得地层声速的提取十分困难.基于管波与地层声波的干涉原理,本文提出了一种声波处理方法.管波的传播特征是已知的,且管波和地层波都由同一声源激发,因此,可以用管波来改造测井声波数据.对改造后数据采用希尔伯特变换作进一步处理,得到与地层信息相关的解析信号,从该信号中即可提取出地层声速.通过对理论模拟数据的处理和现场测井数据的应用,验证了新方法的正确性和有效性.In cased boreholes, acoustic logging waveforms are often contaminated by casing waves, making it difficult to extract formation acoustic velocity from the acoustic data, especially when the casing is poorly bonded with formation. Various methods have been tested to solve the problem with only limited success, due to the weak signal amplitude and poor coherence compared to the dominant casing waves. The new technique of this paper utilizes the modulation of wave power spectrum caused by the interference of casing and formation waves. The advantage of the technique is its ability to suppress the coherence of the casing wave and significantly enhance the coherence of the formation wave, allowing for determining the formation acoustic velocity from the latter wave signal. For an acoustic logging instrument composed of an array of equally spaced receivers, the waveform data containing casing and formation waves are windowed and transformed into frequency domain to obtain the power spectrum for each receiver in array. The average power spectrum of the array is calculated and subtracted from the power spectrum of each receiver, yielding a residue power spectrum. The residue spectrum and its Hilbert transform form the real and imaginary parts of an analytical signal, which, after transformation into time domain, results in a new waveform array data whose phase moveout across array is entirely controlled by the velocity of the formation wave. Processing the new array data using an array velocity analysis method, e.g., the slowness-time-coherence （STC） method, yields the formation slowness behind the steel casing.The new technique was tested on synthetic waveform data calculated for a poorly bonded casing. The synthetic data processing example shows that the technique effectively cancels the coherence of the casing signal and significantly enhances the coherence of the desired formation signal. The technique has also been applied to processing field acoustic logging data acquired in cased boreholes. In depth intervals

关 键 词：套管井测井 管波 波干涉 希尔伯特变换 

分 类 号：P631[天文地球—地质矿产勘探]