鄂尔多斯盆地南部黄土塬区地震资料叠前去噪技术研究

发布时间：2018-06-11 14:39

本文选题：黄土塬 + 叠前去噪　；参考：《西安石油大学》2015年硕士论文

【摘要】：地震数据采集过程中受到外界条件的干扰,得到的地震资料混有大量的噪音干扰,这些干扰能量强,分布广泛,大大降低了资料的质量,也影响了一系列叠前处理工作。对于地震资料处理而言,追求的是高信噪比和高分辨率,高信噪比可以为后续一系列处理工作的精度打下良好的数据基础,高分辨率则为精细地震解释提供有力保障。高信噪比是高分辨率的基础,为了得到高分辨率和高保真度的地震资料,就要做好叠前去噪工作。而在鄂尔多斯黄土塬地区,地形、地貌条件复杂,表层有黄土层覆盖,沟壑纵横,海拔高程变化较大,在黄土、淤泥、砾石等疏松沉积覆盖区,激发、接收条件受到很大的影响,表层低降速带的厚度及速度变化大,地震波吸收衰减严重,在这样的背景下得到的地震资料干扰更为严重,能量更强,频带更宽,信噪比极低。对于黄土塬地区的地震资料,叠前去噪作为提高信噪比的有力手段,更是显得尤为重要。本论文归纳了地震资料中常见的噪音干扰类型,简单讨论了一些噪音的形成机理以及相应的压制方法,具体分析了各种去噪方法的原理以及在使用过程中的优缺点;总结了鄂尔多斯盆地黄土塬区地震资料特点,以及现阶段黄土塬地区叠前去噪技术方法研究现状,并根据研究区地震资料特点制定合理叠前去噪流程,针对不同的噪声类型及其在资料中的频谱特征、能量特征等,在保真保福的前提下,选择合适的方法进行压制;并将地震数据放在不同的数据集和数据域中,分析噪音的特点,使噪音和有效信号的差异最大化,再利用相应的方法去噪。对于近炮点异常能量,本文提出了炮域分频去噪的方法,取得了较好的效果;对于面波等,本论文运用f-x域去噪的方法;对于异常低频和高频强能量则采用了随机道头去噪的方法。此外,本文还进行了室内模拟野外组合激发,探究野外的组合激发对资料处理品质的影响。同时还对处理流程中的去噪次序做出简单讨论,对本文所使用的去噪方法的效果进行了分析。最后对叠前的去噪方法进行了整体总结,尤其对提高鄂尔多斯盆地黄土塬区地震资料信噪比的处理方法进行探讨,对该区地震资料的处理方法有了进一步的认识,得出了适用于研究区的去噪方法,取得了较为理想的去噪效果。
[Abstract]:In the process of seismic data acquisition, the seismic data are disturbed by external conditions, and the seismic data are mixed with a large amount of noise interference. These interference energy is strong and widely distributed, which greatly reduces the quality of data and affects a series of prestack processing work. For seismic data processing, the pursuit of high signal-to-noise ratio and high resolution, high SNR can lay a good data base for the accuracy of a series of subsequent processing work, and high resolution can provide a strong guarantee for fine seismic interpretation. High signal-to-noise ratio (SNR) is the basis of high resolution. In order to obtain high resolution and high fidelity seismic data, pre-stack denoising must be done well. In the loess plateau area of Ordos, the topography and geomorphology conditions are complex, the surface layer is covered with loess soil, the gully is vertical and horizontal, the elevation changes greatly, and in the loose sedimentary cover area such as loess, silt, gravel and so on, it is stimulated, The receiving conditions are greatly affected, the thickness and velocity of the surface low velocity drop zone vary greatly, and the absorption and attenuation of seismic wave are serious. Under this background, the interference of seismic data is more serious, the energy is stronger, the frequency band is wider, and the signal-to-noise ratio is very low. For seismic data in loess tableland, prestack denoising as a powerful means to improve signal-to-noise ratio (SNR) is particularly important. In this paper, the common types of noise interference in seismic data are summarized, and the formation mechanism of some noise and the corresponding suppression methods are briefly discussed, and the principle of various denoising methods and their advantages and disadvantages in the process of application are analyzed in detail. This paper summarizes the characteristics of seismic data in loess tableland area of Ordos Basin, and the present situation of research on pre-stack denoising techniques in loess plateau area, and formulates a reasonable pre-stack denoising process according to the characteristics of seismic data in the studied area. According to different noise types and their spectral and energy characteristics in the data, the proper method is chosen to suppress the noise under the premise of fidelity, and the seismic data is placed in different data sets and data fields to analyze the characteristics of noise. The difference between the noise and the effective signal is maximized, and the corresponding method is used to remove the noise. For the abnormal energy near the shot point, this paper puts forward the method of de-noising in the shot domain, and obtains better results, for the surface wave and so on, this paper uses the de-noising method in f-x domain. For the abnormal low frequency and high frequency strong energy, the method of random trace head denoising is adopted. In addition, the effect of field combination excitation on data processing quality is investigated. At the same time, the de-noising order in the process flow is discussed briefly, and the effect of the denoising method used in this paper is analyzed. Finally, the prestack denoising method is summarized, especially the method to improve the signal-to-noise ratio (SNR) of seismic data in loess plateau area of Ordos Basin is discussed, and the processing method of seismic data in this area is further understood. The denoising method suitable for the research area is obtained, and the better denoising effect is obtained.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.44

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