多次波分离与成像方法研究

发布时间：2018-05-01 04:30

本文选题：多次波分离 + λ-f域Radon变换　；参考：《中国石油大学(华东)》2015年博士论文

【摘要】：相比一次波,多次波在地下传播的反射角更小,覆盖区域更广,可以照明一次波无法到达的阴影区,包含着更为丰富的地下构造信息,因此开展多次波成像方法研究对于地下构造成像质量的提高具有重要的研究意义。而多次波分离是保证目前常用多次波成像方法成功实现的关键。因此,本文开展多次波分离与成像方法研究具有重要的科研价值。论文首先详细阐述了多次波的相关理论,通过多次波正演模拟研究为后文多次波分离与成像方法研究提供数据基础,然后在理论指导与数据准备前提下进一步开展多次波分离与成像方法研究。多次波分离方法研究中,对目前应用最为广泛的基于滤波理论的Radon变换和基于波动理论的表层多次波去除(SRME)方法进行深入研究,发展了多种实用性多次波分离技术。(1)发展了基于λ-f域高分辨率Radon变换的多次波分离方法,该方法通过引入变量消除变换算子对频率的依赖性,结合高分辨率算法,在显著提高计算效率的同时能够较好的保证多次波与一次波分离的精度。(2)在基于波动理论的SRME和聚焦变换理论基础上提出了分离一次波和各阶表层多次波的方法,采用该方法提取的一次波和各阶表层多次波对于获取高精度的多次波成像结果有着重要的研究意义。(3)通过聚焦变换公式推导,得出聚焦变换实质上是多维子波反褶积的过程,因此在聚焦域内由多次波恢复的新数据具有较高的分辨率,通过采用整形正则化非稳态回归自适应匹配滤波法在聚焦域内分离出多次波,即可获取高分辨率数据,该方法从提高高分辨率角度充分利用多次波,对于提高成像质量有重要的研究价值。多次波成像方法研究中,针对地下构造复杂情况不同,分别对基于单程波偏移的多次波成像方法和基于逆时偏移的多次波成像方法开展相关研究,并提出了一系列可行性技术方案。(1)在地下构造较为简单情况下,为了节省成本,可采用基于单程波偏移的多次波成像方法来实现多次波的成像,通过修改边界条件结合偏移精度较高的频率-空间域单程波偏移方法即可实现多次波单程波偏移;为了解决多次波单程波偏移过程中产生的串扰噪音,论文通过引入采用局部斜率和时间多参数同时约束的立体成像条件对不相干同相轴的互相关能量进行去除,模型试算结果验证了该方法的可行性,但是该方法的实用性还有待研究。(2)在地下构造复杂的情况下,基于单程波的多次波偏移无法满足复杂构造成像精度的需求,因此对基于逆时偏移的多次波成像方法展开深入研究。与多次波单程波偏移相比,多次波逆时偏移可以更好的实现地下复杂构造的成像;为了压制多次波逆时偏移过程中由于不相干同相轴互相关造成的串扰噪音,通过对串扰噪音产生过程进行分析,论文提出了一种新的多次波逆时偏移方法,首先通过对基于聚焦变换和SRME分离的各阶多次波进行单独成像,然后将各阶多次波的成像结果进行叠加得到最终的成像结果,与常规的多次波逆时偏移相比,该方法可以有效去除成像结果中的构造假象,提高地下构造的成像精度。(3)层间多次波往往能量较弱,在多次波成像研究中人们通常仅关注表层多次波的成像,但是层间多次波跟表层多次波一样也是来自地下的真实反射,考虑到逆时偏移可以成像特殊波这一特点,本文首先采用逆时偏移对层间多次波的成像进行了分析讨论,验证了逆时偏移可以成像层间多次波,并通过进一步分析,得出采用多次波逆时偏移方法可以成像含层间多次波的表层多次波这一重要结论。结合对多次波分离与成像方法的理论研究,文中分别通过模型试算及实际资料处理对上述研究方法的可行性、有效性及实用性进行了合理的验证。
[Abstract]:Compared with one wave, the reflection angle of the multiple waves is smaller and the coverage area is wider. It can illuminate the unreachable shadow area and contain more abundant underground structure information. Therefore, it is of great significance to carry out the study of multiple wave imaging methods for the improvement of the quality of the underground structure imaging. Therefore, the research of multiple wave separation and imaging has important research value in this paper. Firstly, the theory of multiple waves is discussed in detail. The study of multiple wave separation and imaging is carried out on the basis of theoretical guidance and data preparation. In the study of multiple wave separation, the most widely used Radon transform based on filter theory and the surface multiple wave removal (SRME) method based on wave theory are deeply studied, and many practical multiple wave separation techniques have been developed. (1) (1) the multiple wave separation method based on the high resolution Radon transform of the lambda domain is developed. This method eliminates the dependence of the frequency by introducing the variable operator by introducing the variable, and combines the high resolution algorithm to improve the computational efficiency significantly. (2) the SRME based on the wave theory and the wave theory. On the basis of the theory of focusing transformation, the method of separating primary and surface multiple waves is proposed. The primary and surface multiple waves extracted by this method have important research significance for obtaining high precision multiple wave imaging results. (3) the focus transformation is essentially a multidimensional wavelet deconvolution through the derivation of the focusing transformation formula. As a result, the new data recovered by multiple waves in the focussing domain has high resolution. High resolution data can be obtained by separating multiple waves in the focus domain by using the regularized regularized adaptive adaptive matching filtering method. The high resolution data can be fully utilized to improve the high resolution rate, and the imaging quality is improved. It has important research value. In the study of multiple wave imaging methods, in view of the different complex conditions of the underground structure, the multiple wave imaging method based on the one-way wave migration and the multiple wave imaging method based on the reverse time migration are studied respectively, and a series of feasible techniques are proposed. (1) under the simple underground structure, In order to save the cost, multiple wave imaging method based on one-way wave migration can be used to realize multiple wave imaging. By modifying the boundary conditions and combining the frequency space domain single path migration method with high offset precision, the multiple wave migration can be realized. In order to solve the crosstalk noise produced in the process of multiple wave one-way wave migration, the paper is used to solve the problem of crosstalk noise. The cross correlation energy of uncoherent phase axis is removed by introducing a stereoscopic imaging condition which uses local slope and time multiple parameters simultaneously. The results of the model test verify the feasibility of the method, but the practicability of the method remains to be studied. (2) in the case of complex subterranean structure, the multiple wave offset based on a one-way wave is not. In order to meet the needs of imaging precision of complex structures, the method of multiple wave imaging based on reverse time migration is studied in depth. Compared with multiple wave one-way wave migration, the inverse time migration of multiple waves can better realize the imaging of underground complex structures. In order to suppress the interphase correlation of uncoherent phase axes in the process of pressing the inverse time shift of multiple waves, By analyzing the production process of crosstalk noise, a new method of multiple wave inverse time migration is proposed in this paper. First, the imaging results of each order based on focusing transformation and SRME separation are performed separately, and then the image results of each order multiple wave are superimposed to get the final imaging results, and the regular multiple times are obtained. Compared with the wave inverse time migration, this method can effectively remove the tectonic illusion in the imaging results and improve the imaging precision of the underground structure. (3) the multiple waves between layers often have weak energy. In the study of multiple wave imaging, people usually only pay attention to the imaging of the multiple waves in the surface, but the interlayer multiple waves are the same as the surface multiple waves. In view of the characteristic of the inverse time migration that can imaging special waves, this paper first analyzes and discusses the imaging of interlayer multiple waves by inverse time migration, and verifies that the inverse time migration can be used for multiple waves in the imaging layer. By further analysis, it is concluded that multiple wave inverse time migration method can be used to imaging multi wave surface waves with interlayer multiple waves. This important conclusion. Combined with the theoretical study of multiple wave separation and imaging methods, the feasibility, effectiveness and practicability of the above research methods are verified by the model trial calculation and the actual data processing respectively.

【学位授予单位】：中国石油大学(华东)
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P631

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