基于随机介质正演模拟的塔中顺南地区风化壳储层地震响应特征分析

针对塔中顺南地区奥陶系岩溶风化壳储层地震响应特征识别和储层预测难题,应用随机介质建模方法建立了风化壳缝洞型储层地震地质模型,通过非均匀介质波动方程数值模拟,研究目标储层地震反射波场的运动学和动力学特征,定量分析了储层物性、厚度及其发育位置变化对风化壳反射界面(T⁴₇)地震响应特征的影响。结果表明,当风化壳顶部发育储层时,风化壳反射界面表现为低反射振幅、低频率的地震响应特征。在此基础上优选并验证了对风化壳储层地震响应特征识别相对敏感的均方根振幅和瞬时频率属性,为研究区风化壳缝洞型储层反射特征识别及储层预测提供了一定依据。

In view of the problems of the seismic response characteristics recognition and prediction of the Ordovician karst weathered crust reservoir in Tazhong Shunnan area,by using the random medium theory to build the seismic-geology models of the weathered crust fracture-cavity reservoirs,we investigate the kinematic and dynamic characteristics of seismic reflection wavefield from the target reservoirs based on the numerical simulation of the heterogeneous media wave equation,and quantitatively analyze the reservoir property,thickness and location variation influence on the seismic response characteristics of weathered crust reflection interface(T⁴₇).Comparing the results of forward modeling,we can conclude it shows low reflection amplitude and low frequency features when the weathered crust top develops reservoirs.On the basis,we select mean square amplitude and instantaneous frequency as optimum attributes which are highly related to the characteristics of weathered crust reservoirs.This conclusion will provide a certain reference basis to the prediction and recognition of reflected characteristics of weathered crust reservoirs in Shunnan area.