复杂储层渗透率特性数值模拟

发布时间：2018-06-28 14:21

本文选题：渗透率 + 岩石物理　；参考：《成都理工大学》2015年硕士论文

【摘要】：渗透率是描述多孔介质和裂隙介质中流体流动能力强弱的一个标志。储层渗透率的分布特征直接影响油气的分布、运移和开采,对油气藏的勘探和以后的开发有重要意义。目前许多研究发现,地震响应中包含有储层渗透率信息,因此,本文以岩石物理为基础,研究了砂岩储层渗透率对地震响应的影响特征,以求为实际预测储层渗透率特征提供有效指导。本文基于斑块饱和模型,以三类砂岩储层为例,分析了地震波传播过程中速度频散和衰减现象,以及储层渗透率对其影响的特征:三类砂岩储层中,未固结砂岩储层地震波频散和衰减最明显,其次是中等压实砂岩储层,最后是固结良好砂岩储层;渗透率对地震频散和衰减有明显影响,渗透率越大地震波频散和衰减越强;渗透率影响衰减峰值对应的频率值,随渗透率增大峰值对应的频率值向高频方向移动。以未固结砂岩储层为例,分析了含气-油储层与含气-水储层中地震波频散和衰减的异同,含气-油储层中地震波频散和衰减现象明显弱于含气-水储层,渗透率在含气-油储层中对地震波频散及衰减有明显影响。基于Trapeznikova给出的吸收介质中地震波垂直入射时,反射系数和相位角公式,分析了渗透率对反射系数及相位角的影响特征:渗透率对三类砂岩储层尤其中等压实砂岩储层界面反射系数和相位角有明显影响,甚至会产生相位极性反转。在Trapeznikova反射系数公式基础上,推导了反射系数频率梯度的近似表达式,验证其在Q大于10时与精确式无异;渗透率对反射系数频率梯度有明显影响,渗透率越大反射系数频率梯度越大;对比分析了三类砂岩储层中1/Q和反射系数频率梯度对渗透率变化的敏感性,在中等压实和未固结砂岩储层中,两者敏感度相差不大,而在固结良好砂岩储层中,反射系数频率梯度在高频、低频处敏感度相对较高。采用F-K域波动方程正演模拟研究了渗透率对储层界面反射波振幅的影响特征,三类砂岩储层中,渗透率对储层界面处反射波振幅有明显影响,储层下界面反射波相对上界面有明显衰减,且渗透率越大衰减越强;采用傅里叶变换分析了储层下界面反射波振幅谱特征,渗透率对反射波主频有较大影响,反射波主频随渗透率增加向低频方向移动。基于Zoeppritz方程研究了三类砂岩储层中渗透率对AVO曲线的影响特征,三类砂岩储层中AVO曲线特征不相同;渗透率对AVO曲线影响不大,曲线的基本发展趋势不随渗透率变化而改变;入射角不同渗透率对反射系数的影响不同,入射角越大反射系数对渗透率变化越敏感。综上所述,储层的地震响应中包含有渗透率信息,储层渗透率对地震波频散、衰减及储层界面反射系数、反射振幅等有明显影响。因此本文数值模拟成果对预测储层渗透率特性有指导意义。
[Abstract]:Permeability is a sign to describe the strength and weakness of fluid flow in porous media and fractured medium. The distribution of reservoir permeability directly affects the distribution of oil and gas, and it is of great significance to the exploration and future development of oil and gas reservoirs. Based on rock physics, the influence of sandstone reservoir permeability on seismic response is studied in order to provide effective guidance for the prediction of reservoir permeability characteristics. Based on the patch saturation model, the velocity dispersion and attenuation phenomena during seismic wave propagation and reservoir permeability are analyzed with three types of sandstone reservoir as an example. The characteristics of influence: in the three types of sandstone reservoirs, the seismic wave dispersion and attenuation of unconsolidated sandstone reservoirs are most obvious, followed by medium compacted sandstone reservoirs, and finally the consolidation of good sandstone reservoirs; permeability has an obvious influence on seismic dispersion and attenuation, the greater the permeability is, the stronger the dispersion and attenuation of seismic waves, and the influence of permeability on the corresponding frequency of attenuation peak. An unconsolidated sandstone reservoir is taken as an example to analyze the differences and similarities between seismic wave dispersion and attenuation in gas oil reservoirs and gas and water reservoirs, and the dispersion and attenuation of seismic waves in gas oil reservoirs are obviously weaker than those in gas and water reservoirs, and permeability in gas oil reservoirs is an earthquake. The wave frequency dispersion and attenuation have obvious influence. Based on the vertical incidence of seismic waves in the absorption medium given by Trapeznikova, the formula of reflection coefficient and phase angle is used to analyze the influence of permeability on the reflection coefficient and phase angle. The permeability has an obvious influence on the reflection coefficient and phase angle of the three types of sandstone reservoirs, especially in the medium isobaric solid sandstone reservoir. On the basis of the Trapeznikova reflection coefficient formula, the approximate expression of the frequency gradient of the reflection coefficient is derived. It is proved that it is no different from the exact formula when the Q is greater than 10. The permeability has an obvious influence on the frequency gradient of the reflection coefficient, the greater the permeability is, the greater the frequency gradient of the reflection coefficient, and the comparison and analysis of the three types of sandstone. The sensitivity of 1/Q and the frequency gradient of reflection coefficient to permeability change in the reservoir is very different in medium and unconsolidated sandstone reservoirs. In the well consolidated sandstone reservoir, the frequency gradient of the reflection coefficient is high at high frequency and low frequency. The permeability equation is studied by the forward modeling of the wave equation in the F-K domain. In the three sandstone reservoir, the permeability has an obvious influence on the amplitude of reflected wave at the reservoir interface, and the reflection wave at the lower interface is obviously attenuated, and the greater the permeability is, the greater the permeability is, the Fourier transform is used to analyze the characteristics of the amplitude spectrum of the reflection wave at the lower interface of the reservoir, and the permeability is reflected by the permeability. The main frequency of the wave has great influence. The main frequency of the reflected wave moves with the permeability increasing to the low frequency direction. Based on the Zoeppritz equation, the influence of the permeability on the AVO curve in the three types of sandstone reservoirs is studied. The characteristics of the AVO curve in the three sandstone reservoirs are different; the permeability has little influence on the AVO curve, and the basic development trend of the curve does not change with the permeability. The influence of the different permeability on the reflection coefficient is different, the greater the angle of incidence is, the more sensitive to the permeability change. In summary, the seismic response of the reservoir contains permeability information, and the reservoir permeability has an obvious influence on the seismic wave dispersion, attenuation and the reflection amplitude of the reservoir interface, and the reflection amplitude. The results are of guiding significance for predicting reservoir permeability.
【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】：TE312;P631.4

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