Examinations of acoustic logging tools in the workshop are significant for checking the performance of every unit before field downhole measurements. It is more convenient to test the tools in a horizontally placed open trough rather than in a vertical closed pipe. To ensure the tools can excite and receive the signals from the trough well (i.e. the pipe waves), we should figure out the wave propagation in such an asymmetric structure. We aim for acoustic logging while drilling (LWD) signals from the fluid-filled trough. Both monopole and quadrupole wave fields are studied through the 3D finite difference model. For monopole acoustic logging, first-arrival full waves are the major concern. The propagation velocities of first-arriving pipe waves do not change with opening angles of the trough. The pipe wave speeds are exactly the same as those in closed pipes of the same sizes; while the amplitudes decrease with increasing opening angles. For quadrupole LWD, velocities of pipe waves have few correlations with opening angles and transducer azimuths. The quadrupole source can even excite the monopole collar waves in the trough, which become the first arrivals of the full waves. The quadrupole pipe waves show a trend of being weaker with increasing opening angles. If the opening angle of the trough is too large, the quadrupole pipe waves could totally be covered by other wavelets. To excite clearer pipe wave signals in the trough, it is suggested that an opening angle as small as possible is optimal for the tests.

中文翻译：

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充液槽中钻井工具声波测井的波场数值模拟

在车间进行声学测井工具检查对于现场井下测量之前检查每个单元的性能具有重要意义。在水平放置的开口槽中测试工具比在垂直封闭的管道中测试工具更方便。为了确保工具能够激发并接收来自槽井的信号（即管波），我们应该计算出这种非对称结构中的波传播。我们的目标是在充液槽中钻探（LWD）信号时进行声波测井。通过3D有限差分模型研究了单极和四极波场。对于单极声波测井，首先要注意的是全波。到达管道的传播速度不会随波谷的张开角而变化。管子的波速与相同尺寸的封闭管中的波速完全相同。而幅度随着打开角度的增加而减小。对于四极随钻测井，管波的速度与张角和传感器方位角几乎没有相关性。四极子源甚至可以激发波谷中的单极项圈波，这成为全波的首次到达。四极管波显示出随打开角度增加而变弱的趋势。如果槽的张开角度太大，则四极管波可能会被其他小波完全覆盖。为了在波谷中激发更清晰的管道波信号，建议对于测试而言，尽可能小的打开角度是最佳的。管波的速度与张角和传感器方位角几乎没有关系。四极子源甚至可以激发波谷中的单极项圈波，这成为全波的首次到达。四极管波显示出随打开角度增加而变弱的趋势。如果槽的张开角度太大，则四极管波可能会被其他小波完全覆盖。为了在波谷中激发更清晰的管道波信号，建议对于测试而言，尽可能小的打开角度是最佳的。管波的速度与张角和传感器方位角几乎没有关系。四极子源甚至可以激发波谷中的单极项圈波，这成为全波的首次到达。四极管波显示出随打开角度增加而变弱的趋势。如果槽的张开角度太大，则四极管波可能会被其他小波完全覆盖。为了在波谷中激发更清晰的管道波信号，建议对于测试而言，尽可能小的打开角度是最佳的。如果槽的张开角度太大，则四极管波可能会被其他小波完全覆盖。为了在波谷中激发更清晰的管道波信号，建议对于测试而言，尽可能小的打开角度是最佳的。如果槽的张开角度太大，则四极管波可能会被其他小波完全覆盖。为了在波谷中激发更清晰的管道波信号，建议对于测试而言，尽可能小的打开角度是最佳的。