| 声波远探测中偏心声源的辐射以及接收波场研究 |
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| 引用本文： | 许家旗,胡恒山.声波远探测中偏心声源的辐射以及接收波场研究[J].地球物理学报,1954,63(9):3545-3561. |
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| 作者姓名： | 许家旗 胡恒山 |
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| 作者单位： | 哈尔滨工业大学力学系, 哈尔滨 150001 |
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| 基金项目： | 国家自然科学基金项目（11972132，11734017）资助. |
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| 摘 要： | 通过最速下降积分法获得了充液井孔中偏心点声源激发的井外波场的远场渐近解；利用互易性获得井外存在反射体时井内偏心接收的波场渐近解，渐近解结果与有限差分的结果吻合；分析了声源频率、偏心距离以及方位角对波场辐射与接收的影响.计算发现：声源频率是影响井外波场的主导因素，声源频率较低时，偏心点声源激发的远场波场与偏心距离无关，可以将偏心点声源视为中心声源；声源频率较高时，偏心点声源激发的远场波场与中心声源之间存在不可忽略的差异，且频率越高、偏心距离越大，差异越大.计算还发现：采用偏心声源与偏心接收时，辐射波场与接收波场的幅度都具有方位角依赖性.最后我们给出利用反射波幅度变化来消除反射体方位角180°不确定性的算例.
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| 关 键 词： | 偏心声源 渐近解 声波远探测 方位角 |
| 收稿时间： | 2019-01-07 |
Study on the radiation and reception of the wave field in a single-well imaging system with an eccentric source |
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| XU JiaQi,HU HengShan.Study on the radiation and reception of the wave field in a single-well imaging system with an eccentric source[J].Chinese Journal of Geophysics,1954,63(9):3545-3561. |
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| Authors: | XU JiaQi HU HengShan |
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| Institution: | Department of Mechanics, Harbin Institute of Technology, Harbin 150001, China |
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| Abstract: | The far-field asymptotic solutions to the wave field excited by an eccentric point source in a fluid-filled borehole are derived by the steepest descent integration method. When there is a reflector outside the borehole, the asymptotic solution to the reflected wave field received by eccentric receivers in the borehole is obtained using reciprocity. The asymptotic results are in good agreement with those from the finite difference method. The effects of frequency and eccentric distance on the wave field are analyzed. Simulations show that frequency is the dominant factor affecting the wave field outside the borehole. When the frequency is low, the far-field wave field excited by the eccentric source is independent of eccentric distance, and the eccentric source can be regarded as a central source. When the frequency is high, the difference between the far-field wave field excited by the eccentric point source and the central source cannot be neglected. The higher the frequency and the greater the eccentric distance, the greater the difference is. Simulations also show that the amplitude of the radiated wave field and the received wave field are both azimuth-dependent when using the eccentric source and eccentric receivers. Finally, an example is given to show the elimination of the 180° uncertainty of azimuth angle of the reflector by using the variation of reflected wave amplitude. |
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| Keywords: | Eccentric source Asymptotic solution Single-well imaging Azimuth |
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