Application of Split-frequency AVO Technology in the Evaluation of Middle-depth Thin Reservoirs in the Xihu Depression

Owing to the combination of factors such as the thin layer structure, thickness, and fluid, the wave field characteristics of the thin layer are relatively complex, which results in large uncertainties in the thin layer AVO analysis. To address the complex thin layer simulation problem, this study uses the reflectivity method to conduct AVO forward simulations of thin reservoirs, and finds that the AVO response of the thin layer has an obvious “V” feature at the far offset owing to the tuning effect. Comparing and analyzing the thin layer pre-stack gather in different frequency bands clearly shows that the seismic frequency band is wider and that the AVO amplitude curve of the pre-stack gather is more stable. Using high-resolution time-frequency analysis, the AVO stability can be further improved by performing the frequency scanning analysis on the pre-stacked gather of different frequency bands and selecting the advantageous information of the AVO information that changes stably in the seismic frequency bands to be reconstructed. Through the actual pre-stack gather verification analysis, the advantageous frequency band information of the pre-stack gather can effectively improve the reliability of hydrocarbon detection and provide powerful technical support for the detection of hydrocarbons in the middle and deep layers of the Xihu Depression.