炸药震源激发地震波近场特征试验研究

发布时间：2018-04-04 00:08

本文选题：地震勘探　切入点：炸药震源　出处：《北京理工大学》2015年硕士论文

【摘要】：炸药震源激发地震波的过程较为复杂，涉及多个物理过程。根据波场特征不同，波场可以分为近场和远场。在近场中，炸药震源激发的地震波的能量和频谱特性变化很大。经过一段距离的传播，经过大地滤波，逐渐形成特征较为稳定的波，这一阶段可以看作远场。炸药震源激发条件改变直接影响其产生的地震波近场特征，，从而影响远场地震波特征，而远场地震波的品质是影响地震勘探质量的关键。本文围绕激发条件对形成的地震波的能量和频谱特征的影响规律展开试验研究和理论分析。研究工作得到了几方面的认识和进展： 1）通过对空气、水、沙土和粘土等不同的介质耦合条件下炸药震源爆炸产生的近场地震波特性对比研究发现，以水为耦合介质的炸药震源产生的地震波品质较好，能量和频率相对提高5%-10%。 2）调节不耦合系数可以改变地震波品质，空气耦合条件下，不耦合系数约为1.33左右时为较好耦合条件，激发的地震波品质较好。 3）采用高精度电子雷管实现了分布式震源的精确延时控制。延时叠加震源可以实现提高地震波品质和降低地表震动效果。延迟叠加震源的主频比普通震源要高10%-20%左右，地表震动降低低可达40%。 4）调节炸药震源的药量和长径比也可以改变地震波特征。长径比大的细长药柱和小药量药柱激发的地震波的频率得到了提高。本文研究工作深化了震源激发条件对地震波能量和频谱特征的影响的理解，探索了地震波品质的控制方法，为高精度地震勘探理论和地震激发设计等研究工作提供了基础。
[Abstract]:The process of seismic wave excited by explosive source is complicated and involves many physical processes.According to the characteristics of the wave field, the wave field can be divided into the near field and the far field.In the near field, the energy and spectrum characteristics of the seismic wave excited by explosive source vary greatly.Through the propagation of a distance and the earth filtering, the waves with relatively stable characteristics are gradually formed, which can be regarded as the far field.The change of excitation conditions of explosive source directly affects the near-field characteristics of seismic waves produced by explosives, thus affecting the characteristics of far-field seismic waves, and the quality of far-field seismic waves is the key to affect the quality of seismic exploration.In this paper, the experimental study and theoretical analysis are carried out on the influence of excitation conditions on the energy and spectral characteristics of the formed seismic waves.Several aspects of the research have been recognized and advanced:1) by comparing the near field seismic wave characteristics of explosive source explosion under the coupling conditions of air, water, sand and clay, it is found that the seismic wave produced by the explosive source with water as coupling medium is of good quality.The energy and frequency are increased by 5-10.2) adjusting the uncoupling coefficient can change the quality of seismic wave. When the uncoupling coefficient is about 1.33, it is a better coupling condition, and the quality of excited seismic wave is better.3) accurate delay control of distributed seismic source is realized by using high precision electronic detonator.The delayed superposition of the source can improve the quality of seismic wave and reduce the effect of ground motion.The main frequency of the delayed stack source is about 10%-20% higher than that of the normal source, and the ground motion can be reduced by 40%.4) adjusting the explosive source charge and aspect ratio can also change the characteristics of seismic wave.The frequency of seismic waves excited by long and small charge columns with large aspect ratio is increased.The research work in this paper deepens the understanding of the influence of source excitation conditions on the energy and spectral characteristics of seismic waves, and explores the control methods of seismic wave quality, which provides a basis for the study of high-precision seismic exploration theory and seismic excitation design.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.4

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