一种新的瞬时谱分析技术在致密砂岩气检测中的应用

A New Method of Instantaneous Spectral Analysis Application to the Tight Sandstone Gas Detection

瞬时谱分析技术在地震资料处理和解释中扮演着重要的角色,该方法的优劣取决于时频分析的好坏。常规的线性时频分析方法均是基于傅里叶方法发展起来的,因此受测不准原理限制,使之不能同时具有较高的时间和频率分辨率,且针对非线性非平稳信号的处理效果较差。将基于改进的CEEMD算法的HHT方法应用于致密砂岩气地震资料的瞬时谱分析中,分别从一维地震道,二维地震剖面以及三维地震数据体三个方面进行了实际地震资料含气性检测试验。结果表明该方法在一维地震道时频谱上能够区分含气区;在二维地震剖面的瞬时谱剖面上能发现明显的低频阴影现象;在三维瞬时谱数据体切片中能大致划分含气区域的范围。含气检测结果与测井综合解释结果相吻合,因此方法可以在致密砂岩气地震资料的解释性处理中进行推广。

The instantaneous spectral analysis method plays an important role in seismic data processing and interpretation. The merits of this method mainly depend on the quality of the time-frequency analysis method. The conventional linear time-frequency analysis methods are developed based on the Fourier Transform,and restricted by the uncertainty principle which makes it not have higher resolution in time and frequency domain at the same time. The processing results are also bad for nonlinear and non-stationary signal. The HHT method based on the improved CEEMD algorithm was show which was applied to instantaneous spectral analysis in gas seismic data. Gas testing in seismic data respectively from 1D,2D and 3D seismic data was given. In the 1D seismic data,gas area can be distinguish. In the 2D instantaneous spectral profiles,the low-frequency shadow can be easily observed. In the 3D instantaneous spectral slices,the gas areas can be roughly divided. The results are got match well with logging interpretation. Therefore,the method proposed can be widely promoted in seismic data processing.