Structure Description Method Based on Velocity Modeling Considering 3D Stress Perturbation

During petroleum exploration, the prediction of complex geological structures represents a significant challenge. Conventional isochronal map conversion methodologies may be subject to accuracy limitations due to the influence of in-situ stress perturbations. To overcome this limitation, this study proposes an innovative three-dimensional velocity modeling approach that incorporates in-situ stress perturbations into the optimization process. The methodology has been validated through practical application in oilfield structural predictions. The research methodology involves the construction of a comprehensive 3D geological model, the prediction of stress perturbations, and the establishment of a 3D velocity model derived from lateral variations in vertical normal stress. The approach is systematically structured as follows:1)Development of a structural depth framework based on the integration of isochronal maps and well-log parameter analysis. 2)Construction of a 3D geological model adhering to established patterns of formation density, compression modulus, and shear modulus.3)Utilization of finite element numerical simulations to determine 3D stress fields. 4)Establishment of statistical relationships between interval velocity and stress to facilitate the conversion of stress fields into velocity fields. 5)Generation of isochronal maps with iterative error correction. Comparative analysis of prediction results demonstrates that the proposed methodology exhibits superior performance in terms of structural prediction accuracy and oil-bearing area delineation. The findings underscore the influence of in-situ stress perturbations on the distribution patterns of formation velocities. Furthermore, the integration of stress perturbations into the depth-time conversion process enhances the accuracy of velocity models, demonstrating significant potential for application in more complex geological settings in future studies.