Practice in VSP-Driven Multi-factors “Isochronous Model”-Constrained Inversion for Characterizing Ultra-Deep High-Energy Shoal Heterogeneous Reservoirs

In the exploration of heterogeneous carbonate reservoirs within deep to ultra-deep layers (8000–10,000 m), effectively characterizing the internal heterogeneity of high-energy shoal facies zones is critical. Conventional reservoir inversion methods, which rely on isochronous stratigraphic frameworks, excel at resolving strong seismic reflections but fail to delineate the spatial distribution of small-scale heterogeneous reservoirs within large-scale high-energy shoal systems. To address this, we propose a multi-factor “isochronous” framework-constrained seismic prediction scheme tailored for heterogeneous shoal reservoirs and demonstrate its practical application. The workflow begins with analyzing VSP-driven reprocessed seismic data to extract heterogeneous shoal features. Subsequently, a composite isochronous framework integrating stratigraphic deposition, low-order fault-fracture networks, and reservoir dissolution-enlargement processes is constructed. This framework is embedded as constraints into the inversion process, enabling iterative integration of geological interpretations and seismic inversion results. Ultimately, high-resolution predictions of heterogeneous shoal reservoirs are achieved. Application in the eastern block of Tarim Basin’s Fuman Oilfield demonstrated remarkable efficacy, with drilling success rates exceeding 95%. This methodology shows strong potential for extension to geologically analogous regions.