Fine-scale study and application of velocity-based time-to-depth conversion of the A area, Panyu District

As shown by appraisal wells in structure A in Panyu District, the actual trap geometry differs significantly from its pre-drilling understanding. The analysis shows that the difference is mainly caused by the velocity anomalies in the middle-shallow layers. Breaking through the conventional methods for velocity modeling and correction, this study proposed a new method for velocity correction and variable velocity mapping suitable for the target area. In this method, the causes of velocity anomalies were analyzed based on well data, and then the velocity anomalies were ingeniously combined with seismic amplitude. Accordingly, the trend surface with geological significance for velocity anomaly correction and corrected interval velocities were obtained. The resulting depth-structure map with errors of less than 5 m effectively presented the trap geometry. This study provides a certain reference for the subsequent ascertainment of structures in the same geological setting.