基于叠前数据反演的流体识别新方法

发布时间：2018-05-04 11:05

本文选题：依赖频率的AVO + “暗点”型储层　；参考：《成都理工大学》2015年硕士论文

【摘要】：地震勘探技术不断的进步与提高,且浅层油气储集层不断的勘探与开发,导致勘探目标的区域逐渐的缩小,有效储层预测精度的要求也越来越高,因此需要更有效的流体识别方法。叠后地震数据能够反映同相轴的强弱连续特征,但是对于波阻抗上没有明显特征的复杂油藏的描述存在着很大的问题,而叠前地震数据充分保留地震反射振幅随偏移距或入射角变化的特征。本文基于地震反射振幅随偏移距(或入射角)和频率共同变化的本质特征,主要研究了依赖频率的AVO方法;并且在依赖频率的AVO反演方法中提出了特征频率或频段提取的交会分析方法;同时利用依赖频率的AVO分析方法进行“暗点”型储层的研究;最后将依赖频率的AVO反演方法运用于实际资料,提出了频散程度属性组合型因子。研究的工作和进展包括以下内容:(1)提出了一种新的依赖频率的AVO地震响应数值模拟方法,基于Chapman动态等效介质理论,将依赖频率的速度频散引入反射系数的计算中,利用相移法波动方程正演方法计算依赖频率的AVO叠前角度道集,从而最大程度地挖掘其不同频率地震反射的特征参数(振幅、频散和衰减等)随频率和入射角变化的特征,检测与储层相关的地震频散与衰减异常。(2)对于依赖频率的AVO反演方法参考频率的选择,提出了一种提取特征频率或频段的交会分析方法。可搜索最敏感的特征频率作为叠前频散属性反演的参考频率,从而最大限度地突出储层含不同流体时的频散差异,实现不同流体类型的区分和识别。(3)研究了“暗点”型储层的形成机理及其异常的识别方法。基于Chapman动态等效介质理论与依赖频率的AVO数值模拟方法,引入依赖频率的速度频散效应,形成“暗点”型储层依赖频率的叠前角道集记录,模拟频散砂岩孔隙由水替换为气时与上层弹性介质之间的反射界面振幅减弱(“暗点”)的特征,挖掘砂岩流体替换时地震反射的特征参数随频率和入射角变化的特征。同时利用依赖频率的AVO反演方法计算砂岩含不同流体类型时的纵横波频散程度属性。结果表明砂岩孔隙由水替换为气时,其顶界面的振幅减弱,但频散特征更加明显,并且反演的纵横波频散程度属性在储层顶底界面均出现明显的强异常特征,尤其横波频散程度属性最为明显。说明依赖频率的AVO方法能够克服“暗点”型储层振幅弱的缺点,从而突出与流体信息相关的频散强异常特征,为该类储层的识别提供有效的手段。(4)将依赖频率的AVO反演方法应用于实际资料,取得了较好的效果。基于波阻抗组合型高灵敏度流体识别因子的思想,将纵横波频散程度属性aI与bI组合构建新的流体识别因子。将其应用于实际资料中,使不同流体层的频散程度属性差别增大,有利于突出和放大因孔隙流体所致的储层频散特征异常,减小与流体无关的背景干扰和影响,更加清晰地刻画出有效储层的边界,总体来说对于储层流体识别有较好的效果。
[Abstract]:The continuous progress and improvement of seismic exploration technology and the continuous exploration and development of shallow oil and gas reservoirs lead to the gradual reduction of the area of the exploration target and the higher requirements for the prediction accuracy of the effective reservoir. Therefore, a more effective fluid identification method is needed. There are great problems in the description of complex reservoirs with no obvious characteristics of Yu Bo impedance, and pre stack seismic data fully retain the characteristics of seismic reflection amplitude variation with offset or incident angle. Based on the essential characteristics of the seismic reflection amplitude changing with the offset distance (or incident angle) and frequency, the main study of the frequency dependent AVO is the frequency. In the method of frequency dependent AVO inversion, a rendezvous analysis method is proposed for the extraction of characteristic frequency or frequency band. At the same time, the study of "dark point" type reservoir is carried out by using the AVO analysis method of frequency dependence. Finally, the frequency dependent AVO inversion method is applied to the actual data, and the combination factor of dispersion degree attribute is proposed. The work and progress include the following contents: (1) a new frequency dependent AVO seismic response numerical simulation method is proposed. Based on the Chapman dynamic equivalent medium theory, the frequency dispersion dependence of frequency is introduced into the calculation of the reflection coefficient, and the AVO prestack angle set of dependent frequency is calculated by the phase shift wave equation forward square method. The characteristics of the characteristic parameters (amplitude, frequency dispersion and attenuation) of the seismic reflection of different frequencies (amplitude, frequency and attenuation, etc.) vary with the frequency and incidence angle to detect the seismic dispersion and attenuation anomalies associated with the reservoir. (2) a rendezvous analysis side for extracting characteristic frequencies or frequency bands is proposed for the selection of the frequency of the frequency dependent AVO inversion method. Method. The most sensitive feature frequency can be searched as the reference frequency of the pre stack frequency dispersion property, thus maximizing the dispersion difference of the reservoir with different fluids and realizing the differentiation and recognition of different fluid types. (3) the formation mechanism of the "dark" type reservoir and the identification method of the anomaly are studied. Based on the dynamic equivalent medium of Chapman The qualitative theory and frequency dependent AVO numerical simulation method introduced the frequency dispersion effect of dependent frequency to form a "dark point" type of reservoir dependent prestack trace collection, which simulated the characteristics of the amplitude reduction ("dark point") of the reflection interface between the pore of the dispersion sandstone and the upper elastic medium. The characteristic parameters of the characteristic parameters of the time-varying seismic reflection vary with the frequency and the incidence angle. At the same time, the frequency dispersion degree of the vertical and horizontal waves in sandstone with different fluid types is calculated by using the AVO inversion method of dependent frequency. The results show that the amplitude of the top interface is weakened when the sandstone pores are replaced by water, but the frequency dispersion characteristics are more obvious and the inversion is longitudinal. The intensity attribute of transverse wave dispersion has obvious strong anomaly characteristics at the top and bottom interface of the reservoir, especially the frequency dispersion degree of the shear wave is most obvious. It shows that the frequency dependent AVO method can overcome the weakness of the weak amplitude of the "dark" type reservoir, so as to highlight the characteristics of the strong frequency dispersion related to the fluid information, and provide an effective method for the identification of this kind of reservoir. (4) (4) the frequency dependent inversion method is applied to the actual data, and a better effect is obtained. Based on the thought of high sensitivity fluid identification factor, a new fluid identification factor is constructed by combining the dispersion degree attribute aI of the vertical and horizontal wave and bI, and is applied to the actual data to make the dispersion degree of different fluid layers belong to the different fluid layers. The increase of the sexual difference is helpful to highlight and amplify the dispersion characteristics of reservoir caused by pore fluid, reduce the background interference and influence which is not related to the fluid, and more clearly depict the boundary of the effective reservoir. In general, it has a good effect on the reservoir fluid identification.

【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

【参考文献】