分频波阻抗反演技术在塔中西部台内滩储层预测中的应用

Frequency Division Inversion for the Intraplatform Shoal Reservoir

塔中I号坡折带西段台内滩储层主要发育在上奥陶统良里塔格组,其地震响应以弱振幅响应为主,与东段台缘礁特有的“丘状”外部轮廓和内部发育“串珠状强反射”的地震响应特征有明显差异。台内滩弱振幅储层的优势频段为15-25Hz。优选广义S变换分频方法进行频谱分解,用20Hz分频均方根振幅实现了台内滩储层的预测,通过带通滤波处理得到的优势频段内的纯波数据进行波阻抗反演,能有效地识别出塔中西部上奥陶统良里塔格组的台内滩储层,提高了台内滩储层的识别精度,取得了较好的应用效果。

As an important substitute area,the seismic character of the intraplatform shoal reservoirs in the western area of Tazhong is weak,which is different from the strong beaded-like and moundy-shape reflection of the reef shoal reservoirs.Its responding frequency is 15-25 Hz.According to the distribution character of real seismic data,the generalized S-transform is able to adjust the variation trend of Gaussian window function with the frequency scale to the velocity control of time window width by frequency variation.Spectral decomposition with generalized S-transform is made to qualitatively predict the reservoir distribution.Then an inversion is made to the intraplatform shoal reservoirs by using pure wave data filtered by 15-25 Hz,which improves the recognization accuracy of the mud mound beach in mesa,and achieves a good application effect.