塔中白云岩岩溶储层地震正演模拟及其响应

Seismic Forward Modeling and Its Response of Dolomite Peleokarst Reservoir in Tazhong Area of China

摘要:

针对塔中地区埋深在5 000 m以下白云岩岩溶储层发育的类型和特点,通过建立的2种随机地震地质模型和1种实钻井随机模型,采用弹性波传播交错网格高阶差分模拟方法,分别模拟了基于实际介质模型条件和当岩溶储层孔缝洞内充填物性质发生变化时的地震波场响应.结果表明,对于单层储层厚度大于7 m、子波频率为20~30 Hz的地震响应表现为弱反射能量或呈现峰-谷-峰似串珠状的弱反射特征,当充填物性质由致密到疏松、流体含量增多或子波频率提高时,其串珠状反射能量和强度也明显增强.另外模拟结果还揭示,地震对大于7 m的单层储层

Abstract:

Two stochastic seismic-geological models and one stochastic model for well Zh1 are set up based on the type and characteristics of dolomite Peleokarst reservoir(depth>5 000 m) in Tazhong area,China.Using high-order finite difference method of first-order elastic wave equation,the seismic forward modeling is carried out to determine the seismic response.The results show seismic response is characterized by peakvalley-peak which is like strings of beads when thickness of peleokarst reservoir is not less than 7 m and the wavelet frequency changes from 20 to 30 Hz.The reflection amplitude and strength increases obviously if the filled materials become softer and even become the fluid content or the wavelet frequency increases.It also reveals that seismic resolving power for a single layer of peleokarst reservoir is better than that with a stack of peleokarst reservoir beddings of the same net thickness.