水平薄层包围的流体井孔中声波场的数值模拟

针对声波测井薄层探测的需要,用半解析方法求解了地层为水平多层介质时柱状井孔内脉冲点源激发的声场。通过模式解求出了层间的广义反射矩阵,使得各水平区域的场用层间的广义反射矩阵表出,最后给出了井外为。层介质的形式解,并在井外为三层介质出现一薄层时,对接收器纵向位置位于层下、层间和层上记录的波形进行了数值模拟,得到了首波波至的正确显示。讨论了薄层对波至与幅度的影响。

NUMERICAL SIMULATION OF ACOUSTIC FIELD IN A FLUID-FILLED BOREHOLE SURROUNDED BY HORIZONTICAL THIN-LAYERED MEDIA WITH THE SEMI-ANALYTICAL METHOD

The acoustic wave field excited by a pulsed point source in a fluid-felled borehole surrounded by horizontal multiple-layered media is solved by the send-analytical method. The general reflected matrix between layers is found with the mode solutions so that field of every horizontal region is expressed by the general reflected matrix.The formal solutions of n-layered formation are obtained.Numerival calculation is made on three-layered medial out of borehole. The correct display of head wave arrival is got.The effect of the thin layer on the head wave arrival and amplitude is discussed.The work in this paper make it is possible to investigate the ability to divided layer longitudinally in acoustic logging.