Application of depth migration velocity modeling technology based on multi-information constraint in deep seismic imaging

Accurate seismic imaging of deep, low signal-to-noise ratio zones in faulted basins remains a persistent challenge. To address this, we propose a pre-stack depth migration (PSDM) velocity modeling workflow that integrates multiple information constraints. Shallow velocities are derived from micro-logging constrained first-arrival inversion, while intermediate and deep interval velocities are converted from root-mean-square velocities using horizon-constrained constrained velocity inversion in the depth domain. Horizon-guided residual velocity analysis is iteratively applied from top to bottom, generating a low-frequency velocity model that captures the structural trends of the faulted basin. Multi-attribute constrained grid tomography—incorporating logging curves, azimuth, dip, continuity, and other seismic attributes—iteratively updates interval velocities through PSDM. The workflow combines model-based tomography for macroscopic along-horizon velocity trend control with multi-attribute constrained grid tomography for high-resolution interval characterization, enabling robust delineation of the faulted basin's velocity architecture and improved interval velocity accuracy. Application to 3-D data from Block H in an eastern China oilfield demonstrates clear sequence contacts, abundant interval details, a well-defined deep basement boundary, and improved imaging quality.