时频分析在苏里格地区含气性检测中的应用

地震波通过含气层时高频能量将发生明显衰减,利用地震波高频能量的衰减可预测含气层。首先对比了短时傅里叶变换、小波变换、广义S变换和匹配追踪分解等4种时频分析方法,证实了匹配追踪分解时频分析具有较高的时间域分辨率和频率域分辨率;其次通过模型正演验证了地震波通过含气层时具有高频衰减的特征及高频衰减梯度方法可反映高频能量衰减;最后运用匹配追踪分解法对苏里格气田西部一块三维地震工区进行了时频分析,并应用高频衰减属性进行了含气性检测。其预测结果与钻井的含气性符合率较高,证明该含气性检测方法是可行的。

Application of time-frequency analysis technology to the gas detection in Sulige area

When seismic waves get through gas reservoir, the energy of high frequency will be attenuated. So we can predict oil reservoir by energy of high frequency. Firstly, through the comparison of the four spectrum decomposition algorithm： short-time Fourier transform, wavelet transform, generalized S transform and matching pursuit decomposition, we proved that matching pursuit decomposition method has higher time-frequency resolution. Secondly, we verified that the energy of high frequency will be attenuated when seismic waves get through gas reservoir. Finally, the matching pursuit decomposition method was applied to spectrum decomposition of 3D seismic prospect in Sulige area. Meanwhile, high frequency attenuation was used to predict the gas-bearing properties, and the result is in accordance with actual drilling data, which proves the practicability of this method.