斑状饱和介质的粘弹特性表征与地震波模拟

Viscoelastic representation of patchy saturation media and its seismic wave simulation

将描述斑状饱和介质的储层参数简化为高、低频极限模量和特征频率3个参数,通过数值模拟实验,说明了利用标准线性体(Standard Linear Solid,简称SLS)模型可以定量表征斑状饱和介质的粘弹特征,包括地震波衰减和速度频散特性,进而为研究斑状饱和介质中地震波场特征与储层参数的定量关系提供了一种简单方便、快速有效的技术手段。基于SLS模型,数值模拟了地震波在斑状饱和介质中的传播,分析了斑状饱和介质中孔隙度及含气饱和度的变化对地震波传播特征的影响。研究结果表明:①根据SLS模型模拟的地震记录可以准确提取斑状饱和介质中的地震波衰减和频散特征。②对一个特定储层,在相同孔隙度条件下,某个特定含气饱和度附近,地震波振幅和相位变化最大;在相同含气饱和度条件下,孔隙度越高,地震波波形变化越大。

Reservoir parameters of patchy saturation media are simplified to high and low frequency limit modulus and characteristic frequency.By numerical simulation test,viscoelasticity of patchy-saturated media,including seis mic wave attenuation and velocity dispersion,can be quantitively represented by Standard Linear Solid （SLS） model with the three parameters.So,SLS model is a simple and convenient method to study the relationship between wavefield characteristics and reservoir parameters in patchy saturation media.Seismic wave propagation in patchy-saturated media is numerically simulated based on the SLS model.Then seismic records are analyzed for the impact of different gas saturation and porosity on seismic wave propagation.Numerical results show that seismic wave attenuation and velocity dispersion in patchy-saturated media can be calculated by seismic records.For a certain reservoir of same porosity,there are most significant influence on seismic wave amplitude and phase around a certain gas saturation,while for a certain reservoir of same gas saturation,the seismic waveform changes violently with the higher porosity.