AVO影响因素分析

发布时间：2018-05-04 02:32

本文选题：AVO技术 + Zoeppritz方程　；参考：《成都理工大学》2015年硕士论文

【摘要】：AVO(Amplitude Versus Offset)技术是利用叠前道集上地震反射波振幅与炮检距(或入射角)的关系来研究油气的一种方法。这一技术是在弹性波理论上建立的。从AVO技术产生到现在的二十多年里,随着计算机技术的不断发展,很多的地球物理学家对其做了进一步的分析及研究。在这基础上将它运用在油气地球物理勘探上,并取得了非常好的效果。在查找大量国内外文献的基础上,本文整理了AVO技术的原理及发展过程,对Zoeppritz方程及其简化公式进行了归纳总结,并讨论了AVO分析中的岩石物理参数和含气砂岩定性的分类。为后面AVO影响因素分析做好了铺垫。本文首先以Zoeppritz方程为基础结合实际地震数据进行了AVO正演模拟。实验模拟所得的AVO曲线与各个井的实际AVO曲线均相符,证明了我们所建立的模型是合理的,正演方法具有较高的精度。为详细总结实际地震数据的AVO特征,结合井中储层的解释,分别模拟了储层位于层位顶部和内部情况的AVO特征,分别分析了孔隙度、含水饱和度对AVO曲线的影响。Zoeppritz方程只适用于对两介质之间的一个分界面求取其反射、透射系数,其只能够反映一个分界面的特征,却不能够对一个层的内部特征进行描述,特别是对薄层的特征。本文对层状介质、厚层和薄层做了一定介绍,利用Berkhovski方程进行推导,得出了三层介质的薄层反射、透射系数公式。并建立了相关的薄层模型,通过得出的公式对其进行了反射系数曲线分析。分析了中间夹层的厚度和入射波频率对反射系数曲线的影响。由于地层的吸收作用,当中间夹层厚度比较大时,其反射系数曲线随着厚度的增大震荡越来越厉害。考虑到地层吸收作用的影响,引入了品质因子。将1978年Frayer提出的品质因子表示的复波速代替前面Brekhovski方程中的波速,得到了中间夹层有吸收的反射系数公式。利用这一公式分析了地层吸收作用对反射系数曲线的影响。
[Abstract]:AVO(Amplitude Versus offset technique is a method to study oil and gas by using the relationship between amplitude of seismic reflection wave and offset (or incident angle) on prestack gathers. This technique is based on elastic wave theory. With the development of computer technology, many geophysicists have made further analysis and research on AVO technology in the past twenty years. On this basis, it has been applied to oil and gas geophysical exploration and achieved very good results. On the basis of looking up a large number of domestic and foreign literatures, this paper arranges the principle and development process of AVO technology, sums up the Zoeppritz equation and its simplified formula, and discusses the rock physical parameters and classification of gas bearing sandstone in AVO analysis. It lays the groundwork for the analysis of the influencing factors of AVO. In this paper, based on the Zoeppritz equation and the actual seismic data, the AVO forward simulation is carried out. The simulated AVO curves agree with the actual AVO curves of each well. It is proved that the proposed model is reasonable and the forward modeling method has high accuracy. In order to summarize the AVO characteristics of the actual seismic data in detail, combined with the interpretation of the reservoir in the well, the AVO characteristics of the reservoir located at the top of the horizon and the internal situation are simulated, and the porosity is analyzed respectively. The effect of water saturation on the AVO curve. Zoeppritz equation can only be used to calculate the reflection and transmission coefficient of an interface between two media, which can only reflect the characteristics of a boundary surface, but cannot describe the internal characteristics of a layer. Especially for the characteristics of the thin layer. In this paper, the layer medium, thick layer and thin layer are introduced, and the reflection and transmission coefficient formulas of three layers are derived by using Berkhovski equation. The related thin-layer model was established and the reflection coefficient curve was analyzed by the formula obtained. The influence of the thickness of interlayer and the frequency of incident wave on the reflection coefficient curve is analyzed. Because of the absorption of the stratum, when the thickness of the intermediate interlayer is large, the reflection coefficient curve oscillates more and more with the increase of the thickness. Considering the influence of stratigraphic absorption, the quality factor is introduced. In this paper, the complex wave velocity expressed by Frayer in 1978 is replaced by the wave velocity in the previous Brekhovski equation, and the reflection coefficient formula with absorption in the intermediate interlayer is obtained. The influence of the formation absorption on the reflection coefficient curve is analyzed by using this formula.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.4

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