页岩岩石物理响应及AVO技术

发布时间：2018-05-10 13:17

本文选题：页岩 + 岩石物理　；参考：《吉林大学》2015年硕士论文

【摘要】：随着世界经济的不断发展，油气资源的需求越来越大，而可再生的替代能源进展缓慢，非常规储层的油气资源越来越受到重视。页岩储层中的油气在非常规储层油气中占有相当大的比例，所以页岩岩石物理模型的研究是具有十分重要的意义，其成果可以为地震反演提供理论依据。页岩岩石物理模型在地震勘探领域中的研究已经起步，这里页岩岩石物理模型包含两类：一类是富有机质页岩模型，这里富有机质页岩是孔隙中充填干酪根（固体有机质）、油、水等的页岩模型；另一类是水平层理缝的页岩模型，页岩为沉积岩，水平层理比较发育，其中含有一些微裂隙，这些构成油气流动的通道。这两类模型都能描述横向各向同性的页岩介质。富有机质页岩模型前人已经讨论了反射系数与干酪根含量、入射角以及地层厚度的变化关系。在此基础上加入频率的影响，通过传播矩阵算法，计算不同厚度的富有机质页岩模型的地层反射系数，得到不同干酪根含量的频变反射系数随入射角变化的关系，进而加入子波的影响得到反射波的地震合成记录。水平层理缝的页岩模型是把已有的Hudson裂缝模型和Schoenberg裂缝模型应用在页岩介质上，即背景岩石为页岩。通过传播矩阵算法，计算水平层理缝页岩模型的地层反射系数，得到不同裂缝密度下的频变反射系数随入射角变化的关系，再加入子波的影响得到反射波的地震合成记录。结果表明地震反射特征对干酪根含量以及裂缝密度都很敏感。对于富有机质页岩模型，地层厚度增加会使频变反射系数中频率周期变小，干酪根含量增加使富有机质页岩层的速度降低，改变页岩岩石的各向异性，使得地层的波阻抗差异变大，因此反射波振幅增强。裂缝密度增加，使得页岩层垂向速度降低十分明显，，导致页岩岩石的各向异性增强、波阻抗差异变大，反射波振幅明显增强。本文还进行了部分探索性的研究，由于页岩层也会存在一些微裂隙的结构，使得一些页岩层具有较低的渗透性，渗透率的增加会使地震波波速变小。裂缝或孔隙中充填流体会使得入射波经过时产生的有效应力减小，这个有效应力减小会使得地震波速度变小。
[Abstract]:With the development of the world economy, the demand for oil and gas resources is increasing, and the renewable alternative energy is developing slowly, and the oil and gas resources of unconventional reservoirs are paid more and more attention. Oil and gas in shale reservoir account for a large proportion of oil and gas in unconventional reservoirs, so the study of shale rock physical model is of great significance, and its results can provide theoretical basis for seismic inversion. The physical model of shale rocks has been studied in the field of seismic exploration. There are two types of physical models of shale rocks: one is organic shale model, where organic shale is filled with kerogen in pores (solid organic matter, oil, oil). The other is the shale model of horizontal bedded fractures, which is sedimentary rock, and the horizontal bedding is relatively developed, which contains some micro-fractures, which constitute the passage of oil and gas flow. Both models can describe transversely isotropic shale media. The relationship between reflection coefficient and kerogen content, incidence angle and formation thickness has been discussed in the model of rich organic shale. On this basis, the influence of frequency is added, and the reflection coefficient of organic shale model with different thickness is calculated by propagation matrix algorithm, and the relationship between frequency varying reflection coefficient and incident angle of different kerogen content is obtained. Then the seismic synthetic record of reflected wave is obtained by adding the influence of wavelet. The shale model of horizontal bedding fracture is to apply the existing Hudson fracture model and Schoenberg fracture model to the shale medium, that is, the background rock is shale. Through the propagation matrix algorithm, the formation reflection coefficient of horizontal bedding fracture shale model is calculated, and the relationship between frequency variation reflection coefficient and incident angle under different fracture density is obtained, and the seismic synthetic record of reflected wave is obtained by adding the influence of wavelet. The results show that seismic reflection is sensitive to kerogen content and crack density. For the organic shale model, the increase of formation thickness will reduce the frequency period in the reflection coefficient of frequency variation, and the increase of kerogen content will decrease the velocity of organic matter rich shale layer and change the anisotropy of shale rock. The difference of wave impedance becomes larger, so the amplitude of reflected wave increases. With the increase of fracture density, the vertical velocity of shale layer is obviously decreased, and the anisotropy of shale rock is enhanced, the difference of wave impedance is increased, and the amplitude of reflection wave is obviously increased. Some exploratory studies have also been carried out in this paper. Due to the existence of some micro-fracture structures in shale beds, some shale formations have lower permeability, and the increase of permeability will make the seismic wave velocity smaller. The filling fluid in fracture or pore will reduce the effective stress when the incident wave passes by and the decrease of the effective stress will reduce the velocity of seismic wave.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.4;P618.13

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