基于谱反演的薄层预测技术应用探讨

Discussion on the Application of Thin-Reservoir Predication Technology based on Spectrum Inversion

本文从实际的地质地震模型出发,分析了实际情况下峰值振幅、峰值频率随地层厚度的变化规律,其与Widess模型得出的结论有很大的不同:在地层厚度减为零时,峰值振幅并未减弱至零;峰值频率随着地层减薄有逐渐变大的趋势,当层厚小于一定厚度(调谐频率转折点)时,峰值频率开始减小,在层厚为零时与子波的主频一致。当地层薄到一定程度后,峰值频率会与厚度产生强烈的关联,这表示地震对薄层的响应远比我们之前想象的要敏感的多。基于以上理论分析,本文采用谱反演薄层预测技术对FL地区茅口组岩溶薄储层进行预测,精确识别出了薄储层的顶底界面,取得了良好的应用效果。

The paper has analyzed the law of the peak amplitude and the peak frequency varying with the formation thickness under the actual situation based on geologic earthquake models and the analysis results are different with the conclusion drawn from the model Widess： The peak amplitude remains unchanged when the formation thickness drops to zero; the peak frequency tends to gradually increase with the thinning of the formation. When the formation thickness is reduced to a certain extent （the turning point of the tuning frequency）, it starts to fall; when the formation thickness reaches zero, and it is the same as the dominant frequency of the wavelet. The peak frequency will be closely associated with the formation thickness after the latter is attenuated to a certain degree, which suggests the response of the earthquake to the thin reservoir is far more sensitive than previous anticipation. The paper has precisely identified the top and bottom interfaces of thin reservoirs and obtained good application effects by forecasting the thin karst reservoirs in the Maokou Formation within FL area with the spectrum inversion prediction technology based on the above theoretical analysis.