【摘要】 李鹤升 ,李宁 .偶极声源激发的波频散特性 .石油地球物理勘探 ,2 0 0 2 ,37(5 ) :4 4 1～ 4 4 5 ,4 5 4　　偶极声源在地层井内激发的波是频散波 ,已经有许多文章讨论了它的频散特性 ,并涉及了频散校正问题 ,但主要讨论它的最低模式 (即截止频率最低的那一条曲线 ) ,而对于其他模式则没有进行比较详细的讨论。本文根据地层横波速度与泥浆速度相比高、接近、低的三种情况把地层分为硬性地层、中性地层和软性地层 ;给出了单极和偶极两种声源在这三类地层中激发的频散波的频散曲线。结果表明 ,这两种声源激发的频散波具有很强的可对比性 ,它们的最低模式在单极声源激发时是斯通利波 ,在偶极声源激发时是弯曲波 ;两种声源的其他模式处于截止频率时 ,在硬性地层中的速度趋于横波速度 ,在软性地层中速度趋于纵波速度 ,中性地层只有一个模式更多还原

【Abstract】 The wave excited in a fluid filled borehole by a dipole acoustic source is dispersive wave,which characters and related correction have been discussed in many articles,but they only deal with its lowest mode(that is the dispersive curve naming the lowest cut off frequency)as for other mode,the articles have no detail discussion.Dividing the formation into hard,medium and soft types three cases,according to that the velocity of shear wave in formation is higher than that,is approaching to that and is lower than that in mud,the paper presents the dispersive curves of dispersive wave excited in these three formation by monopole and dipole.The results show that the dispersive wave excited by these two acoustic sources have strong contrast,which are Stoneley wave for monopole and flexural wave for dipole in the lowest mode.The other modes of the two acoustic sources at cut off frequency are approximate to shear velocity in hard formation and P wave velocity in soft formation separately.There is only one mode for medium formation.更多还原