Seismic time-frequency analysis based on VMD and envelope derivative operator for fractured-vuggy reservoir prediction

Deep fracture-vuggy carbonate reservoirs are characterized by scattered spatial distribution and quite different internal structures. Time-frequency analysis methods such as Hilbert-Huang transform, ensemble empirical mode decomposition and complete ensemble empirical mode decomposition always encounter problems like modal aliasing and endpoint effect when applied to reservoir prediction. In this paper, we propose a high-accuracy time-frequency analysis method which combines Variational Mode Decomposition (VMD) with Envelope Derivative Operator (EDO). The VMD method can adaptively and non-recursively decompose original seismic signal into a series of band-limited quasi-orthogonal IMFs. The EDO operator with good non-negative characteristics and anti-noise ability can calculate the instantaneous amplitude and frequency of selected IMFs which contain effective information in every frequency band instead of Hilbert transform method. The final time-frequency distribution can track energy change to predict fractured-vuggy reservoirs. Application of the VMD-EDO method in real seismic data has verified its effectiveness in improving time-frequency resolution, and characterizing energy anomalies hidden in broadband seismic data. Considering the reservoir characteristics of "low-frequency energy strengthened and high-frequency energy attenuated", the VMD-EDO method is valid for oil and gas detection. © 2021, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.