饱含流体介质的地震波场特征及频率分布

地震波在含流体地层中传播时, 由于受到流体的粘滞性和内摩擦等阻力的影响, 其波场较不含流体时要发生显著变化。为了定性地研究地震波的这种波场特征及变化规律, 该文将Korneev 等人提出的一维弥散、粘滞型波动方程拓展为二维形式, 推导了二维弥散、粘滞型波动方程的解, 并通过数值模拟分析和归纳了含流体地震波场随粘滞性衰减系数和弥散耗损系数变化而变化的特征和规律,为储层识别和预测提供了理论依据和指导。结果显示, 粘滞性衰减系数主要影响地震波的频率分布,随着其值的增大地震波的主频迅速低移; 弥散耗损系数主要影响地震波振幅的衰减, 而几乎不改变地震波的频率分布。

Seismic wave field characteristics and frequency distribution in fluid-saturated media

When the seismic wave propagates in fluid-saturated stratum, its wave field changes compared with the case of none fluid, because of the influence of resistance such as the viscosity and diffusion of the fluid. Based on the one-dimensional diffusive and viscous wave equation, two-dimensional diffusive and viscous wave equation is derived. The characteristics and rule of the change of seismic wave field are analyzed by numerical simulation, which provide guidance and criterion for the reservoir identification and prediction. The result shows that viscosity coefficient mainly affects the frequency distribution of seismic wave, and diffusion coefficient mainly controls the attenuation of seismic wave with no influence on the frequency distribution.