相控线阵声波测井辐射器物理模拟实验波形分析

Analysis on waveform trains in physical simulation on acoustic logging with linear phased array transmitter

以声波波形的两个最基本的特征振幅和频率为研究对象,分析了相控线阵声波测井辐射器做发射器时在模型井内测量的全波列波形,并考察了相控线阵的相邻阵元间激励信号的延迟时间、阵元个数等因素对测井波形的影响。实验结果表明,随着相邻阵元间激励信号延迟时间的增加,相控线阵的辐射声束指向角不断变大,先后满足滑行纵波临界折射和滑行横波临界折射条件,使充液井孔中的滑行纵波、滑行横波和斯通利波分别得到加强。随着相邻阵元间激励延迟时间的增加,纵、横波的主频值发生漂移,当满足滑行纵(横)波临界折射条件时,纵(横)波波包的主频值最高,幅度值最大。随着相控线阵工作阵元个数的增加,在近似满足同相位叠加时,纵、横波振幅得到明显的加强。

The waveform trains gotten by laboratory simulation on acoustic logging with phased array transmitter was studied by the amplitude and frequency of the waveforms. The influential factors of delay time exerted on neighboring elements and element number were analyzed. The experimental results show that by increasing delay time exerted on neighboring elements, steered radiation angle of the phased array becomes larger and larger, and generation conditions of the refracted compressional wave and the refracted shear wave are reached successively, and the refracted eompressional wave, refracted shear wave and Stoneley wave are strengthened respectively. And simultaneity the dominant frequency of compressional or shear wave reaches to the highest value. By increasing the number of the elements, the amplitudes of eompressional wave and shear wave are enhanced in the generation condition.