An Improved Transient-Extracting Transform With Application to Seismic Data

The time–frequency (TF) characteristics of seismic signals make it possible to accurately identify the boundaries of natural gas. In particular, the transient-extracting transform (TET) improves the time resolution of the unstable signal TF representation (TFR) by extracting only the points on the group delay (GD) trajectory. However, the GD estimator of TET lacks certain accuracy for frequency-varying signals. To overcome this problem, this article proposes an improved GD (IGD) estimator. First, in the short-time Fourier transform (STFT) domain, based on the GD estimator of the frequency-varying signal, the GD estimator problem is transformed into a fixed-point problem, and the IGD estimator is constructed. Then, combining the advantages of TET, an improved TET was proposed. Finally, through the simulated geological model test of ITET, the root mean square error of the model’s reflectivity structure is only 0.001. Combined with the analysis of seismic data, the effectiveness of this method in the positioning of reflectivity structure is verified, which can provide strong support for subsequent seismic interpretation.