As the exploration and development of the basin continue to advance, the proportion of hydrocarbon reservoirs characterized by small scale, low structural relief, and complex faulting has been increasing year by year. Fine mapping of low-relief structures is a key technical challenge in the evaluation of such reservoirs, and its accuracy is primarily constrained by the precision of seismic data processing and velocity analysis. Taking X Oilfield in the Pearl River Mouth Basin as an example, this study proposes an integrated time–depth conversion method that combines seismic and well-log velocity data. Through steps such as horizon-guided velocity picking, average velocity field establishment, macroscopic trend correction, and spatial residual factor correction between wells and seismic data, a high-precision average velocity model is constructed. Practical applications demonstrate that this method can control the depth error of the target horizon structural map within 3 m, effectively supporting the fine characterization of low-relief structures and reservoir evaluation. The velocity analysis workflow established in this study can provide reliable technical reference for time–depth conversion of low-relief structures under similar geological conditions.
Hou et al. (Wed,) studied this question.