## 3 Results
### Field-Data Example  
The study area is located in a typical strike-slip fault zone in western China, covering approximately 100 km\({}^{2}\). The region is characterized by complex structural settings, predominantly controlled by NE-trending strike-slip faults. Multiple sets of secondary and intersecting faults are developed within the fault zone, forming diverse structural patterns. The target interval is the Ordovician Yijianfang Formation, which is primarily composed of marine carbonate sediments. The strata are generally subhorizontal, with dense lithology and well-developed fractures. Reservoir properties are highly heterogeneous and largely controlled by the development of the fault-fracture system. Notably, due to the intensive faulting and fracturing, the target interval exhibits weak and discontinuous seismic reflections with a relatively low signal-to-noise ratio, which presents challenges for structural interpretation. In particular, internal secondary faults and small-scale fractures play a critical role in controlling reservoir connectivity and fluid migration pathways, making their accurate identification essential for reliable reservoir characterization. It is worth noting that several wells in this area have experienced severe lost circulation while drilling through fault-intensive zones, indicating high permeability and connectivity within the structurally controlled fracture networks. This further underscores the urgent need for high-resolution structural identification in engineering practice. In this study, the seismic dataset used consists of 800 inlines (W-E) \(\times\) 800 crosslines (S-N), with a time sampling interval of 1 ms and a spatial sampling interval of 25 m in both directions. This dataset provides the necessary foundation for identifying small-scale structures and discontinuities. To assess the effectiveness of multi-frequency OOCA coherence in resolving fault structures of different scales, Figure 8 presents directional coherence slices extracted at 10 Hz, 25 Hz, and 35 Hz, along with the fused result. At 10 Hz (Figure 8a), the major strike-slip fault extending from south to north is clearly delineated, exhibiting strong continuity along its length (blue arrows). This low-frequency component effectively enhances large-scale reflector alignment but shows limited ability to resolve internal fault complexity or minor discontinuities. \begin{table}
\begin{tabular}{c c c c} \hline
**Method** & **Fractures Identified (Out of 95)** & **Detection Accuracy (\%)** & **Minimum Resolvable Width (m)** \\ \hline C3 Coherence & 71 & 74.7 & 30 \\ Instantaneous Phase & 76 & 80 & 20 \\ OOCA & 88 & 92.6 & 10 \\ \hline \end{tabular}
\end{table} 
Table 1: Detection performance on physical model data. In the 25 Hz coherence slice (Figure 8b), several secondary faults begin to emerge within the main fault zone (yellow arrows). These structures are partially resolved but remain blurred or discontinuous in certain segments, suggesting an improved but still limited response to medium-scale deformation. The 35 Hz slice (Figure 8c) highlights small-scale details more distinctly. Secondary faults are better separated and more clearly defined (green arrows); however, the continuity of the main fault deteriorates, with noticeable interruptions along its trace, indicating a trade-off between resolution and structural coherence at higher frequencies. The fused result (Figure 8d) successfully integrates the complementary advantages of all frequency components. It maintains the strong lateral continuity of the main strike-slip fault while enhancing the clarity of secondary fault patterns within and around it (red arrows). Both fault boundaries and internal fracture details are well preserved, offering improved structural completeness and interpretability. This fusion result demonstrates the proposed method's capacity to simultaneously image large-scale tectonic frameworks and fine-scale discontinuities, which is essential for accurate structural interpretation in fault-dominated reservoirs.