We propose an approach for TTI velocity model building that utilizes the well mis-tie information as inversion constraints. We address two practical issues of the ray-based tomographic inversion: 1) Spatial sparsity of available wells and 2) Ray instability caused by high velocity contrast. We resolve the first issue by extrapolating the well constraints from sparse well locations to their surrounding areas. The extrapolation is performed by solving a system of differential equations, following local geological structures. For the second issue, we utilize angle domain tomography. Since reflection angles are available from angle gathers from RTM, velocity inversion can be limited to areas where no high velocity contrast structures (e.g., salt domes) exist. The resulting inversion scheme ameliorates the ray instability and mitigates the ambiguity among the inverted TTI model parameters and the ill-conditioning of the inversion operator and hence improves the robustness of the solution. We elaborate in detail this approach in this abstract and demonstrate with a real data example that the proposed method has not only improved the positioning of the depth migrated image, but also flattened common image gathers.
Presentation Date: Monday, October 12, 2020
Session Start Time: 1:50 PM
Presentation Time: 3:30 PM
Location: Poster Station 8
Presentation Type: Poster
