二维超声物理模拟波场快照研究

发布时间：2018-03-25 01:01

本文选题：波场快照　切入点：超声地震模拟技术　出处：《西南交通大学》2017年硕士论文

【摘要】：波场快照能够全面清晰直观地显示出地震波在介质中传波的时空图像,对于认识和研究复杂条件下构造、物性和岩性等多种地质因素与地震波之间的响应特征(波场特性)具有极大帮助,而波场特性是地震勘探领域内解释资料时必不可少的依据。尽管由于物理模拟方法技术的限制,数值模拟目前仍是获取地震波时空传播的波场快照的主要方法,但物理模拟在地震波场的认识和研究中的重要性和不可替代性一直促使地球物理学者发展通过物理模拟获取波场快照的方法。本文从二维地震模型的理论出发,结合地震波第一菲涅尔带半径理论(横向分辨率)以及观测条件限制(激发传感器尺寸),对实验中所用二维模型的厚度进行研究,然后结合超声地震物理实验的基础理论,运用基于虚拟仪器技术搭建的超声物理实验观测系统,以及设计的针对波场快照数据采集的观测方案,对制作的二维均匀介质模型和二维横向非均匀介质模型进行实验,并将测得的实验数据应用编制的数据处理程序进行处理,最后利用处理后的数据绘制二维波场快照,并提取使用本方法测得的近自由表面记录的瑞利面波的频散特征,与相应数值模拟结果进行对比分析,来验证本实验方法的可行性和可信度。最终得到了均匀半空间和横向非均匀半空间模型的二维波场快照。以两种模型的实验观测和处理后数据绘制的波场快照以及近自由表面记录的瑞利面波的频散特征,与对应的二维数值模拟的结果对比,二者具有很好的一致性,验证了超声物理技术模拟波场快照方法的可行性和可信性。研究结果表明,本文提出的物理模拟方法具有直观地揭示二维复杂介质中全波震像的时空响应特征的优势。
[Abstract]:The snapshot of the wave field can show the space-time image of the seismic wave in the medium clearly and intuitively. Many geological factors, such as physical property and lithology, are of great help to the response characteristics (wave field characteristics) between seismic waves. The characteristics of the wave field are the essential basis for interpreting the data in the field of seismic exploration, although the numerical simulation is still the main method to obtain the snapshot of the seismic wave propagation in time and space due to the limitation of the physical simulation method and technology. However, the importance and irreplaceable importance of physical simulation in the recognition and study of seismic wave field has led geophysicists to develop the method of obtaining wave field snapshots by physical simulation. Combined with the first Fresnel band radius theory of seismic wave (lateral resolution) and the observation condition (excitation sensor dimension), the thickness of the two-dimensional model used in the experiment is studied, and then the basic theory of ultrasonic seismic physics experiment is combined. The ultrasonic physical experiment observation system based on virtual instrument technology and the observation scheme designed for the data acquisition of wave field snapshot are used to test the two-dimensional homogeneous medium model and the two-dimensional transverse non-uniform medium model. The measured experimental data are processed by the data processing program, and the 2D wave field snapshots are drawn using the processed data, and the dispersion characteristics of Rayleigh surface waves recorded on the near free surface by this method are extracted. Compared with the corresponding numerical simulation results, Finally, 2-D wave field snapshots of homogeneous half-space and transverse non-uniform half-space models are obtained. The wave field snapshots drawn from the experimental observations and processed data of the two models are used. And the dispersion characteristics of Rayleigh surface waves recorded near the free surface, Compared with the corresponding two-dimensional numerical simulation results, the two methods are in good agreement, and the feasibility and credibility of the ultrasonic physics simulation method for wave field snapshot are verified. The physical simulation method presented in this paper has the advantage of directly revealing the space-time response characteristics of full wave seismic images in two-dimensional complex media.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P631.4

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