Research on Multi-scale 3D Modeling Methods for Complex Geological Bodies Based on Grid-TIN Coupling

3D geological modeling of large sedimentary basins often encounters challenges in expressing complex geological structures and multi-scale features. A single modeling method struggles to balance global continuity with local detail precision. Taking the Tarim Basin as an example, this paper proposes a hybrid modeling technique based on regular grids (Grid) and irregular triangular networks (TIN). The Grid model efficiently represents the large-scale continuous sedimentation characteristics of the basin through uniform grids, while the TIN model accurately depicts local complex structures such as faults and folds. The study adopts a “hierarchical construction-dynamic fusion” technical route, embedding multi-scale TIN submodels within the Grid framework. By utilizing boundary constraint algorithms, seamless integration and gradient transitions between the two models are achieved, effectively addressing the issue that traditional single modeling methods face in balancing global continuity and local finesse. Practical applications demonstrate that this hybrid model significantly improves upon single models in expressing geological body contact relationships and attribute interpolation accuracy, providing more reliable spatial data support for hydrocarbon resource prediction and basin evolution analysis. It offers valuable references for multi-method collaborative modeling of complex geological bodies.