## 3 Analysis and Discussion of Physical Modeling Results
### Fractured Reservoirs with Various Dip Angles  
After identifying the fractured reservoir corresponding to the SBLR, the effect of fracture dip on the SBLR was analyzed first. The SBLRs of the top of the Yingshan Formation and the fourth member of the Yingshan Formation were extracted from the seismic migration data, as well as their waveform and frequency profiles. The fractured reservoirs showed a \"valley-peak-valley\" pattern in the top of the Yingshan Formation (Figures 8 and 9). When the fracture dipping angle was 0-30\({}^{\circ}\), the SBLRs, also called the string of wide bead responses (SWBRs), were relatively obvious, sheet-like, and easy to recognize. These SWBRs had a right-skewed symmetric waveform pattern of \"valley-peak-valley\" horizontally, in which the wave peak was stronger, and the energy of the front valley was stronger than that of the latter valley. In the vertical direction, these had relatively weak but generally continuous reflections at the top, strong and continuous reflections in the center, and weak and relatively disorganized reflections at the bottom. When the dipping angle was 10-20\({}^{\circ}\), the events were similar to that of the real fracture, and the continuity of the wave peak was stronger. When the dipping angle was 30\({}^{\circ}\), the events showed an S-shape, and the part of the frequency profile above 25 Hz was similar to the morphology of the reservoir. These results are consistent with real seismic data [18, 36, 41] and numerical simulations [3, 4]. When the dipping angle of the fractured reservoir were a high angle of 70-90\({}^{\circ}\), the events gradually changed from S-shapes to X-shapes, which were tadpole-shaped and messy, and it was difficult to recognize them. The dipping angle of the events was no longer similar to that of the reservoir. When the dipping angle was 70-80\({}^{\circ}\), the top and bottom reflections was stronger, and the center reflection was weaker or even blank. At a dipping angle of 90\({}^{\circ}\), the top and bottom reflections were weaker, the center reflection was stronger, and the events axis was X-shaped, showing a narrow bead-like pattern in the center of the X-shape. In the frequency profile, the morphology and location of the low frequencies were more consistent with the fractured reservoir as the dipping angle increased for high angles from 70\({}^{\circ}\) to 90\({}^{\circ}\). From the seismic and waveform profiles, it was shown that the center maximum amplitude decreased with an increasing dipping angle for low angles from 10\({}^{\circ}\) to 30\({}^{\circ}\) and  
Figure 10: Model and results in the Penglaiba Formation. The profile location is identical to that of the green box in Figure 7. (**a**) Model of fracture reservoirs. (**b,c**) are the color and waveform plots of the migration results, respectively. (**d**) Frequency attribute. increased with an increasing dipping angle for high angles from 70\({}^{\circ}\) to 90\({}^{\circ}\). In the frequency profile, the frequency was smaller when the fracture was horizontal; the frequency decreased with an increasing dipping angle from 10\({}^{\circ}\) to 90\({}^{\circ}\) (Figures 8 and 9). The comparison of the low-angle fractured reservoir A7 affected by the overlying strongly reflected strata with the other low-angle A1, A2, and A3 fractured reservoirs shows that the low-angle fractured reservoirs affected by the overlying strongly reflected strata had smaller amplitudes and frequencies. The comparison of the high-angle fractured reservoirs A5 and A6, which were affected by the overlying strongly reflected strata, with the fractured reservoir A4, which was not affected, shows that the high-angle fractured reservoirs were relatively less affected (Table 3). In general, when the dipping angle of the fracture was smaller, the seismic reflected wave from the fracture had a superposition effect with that from other strata, which were smaller in frequency and larger in amplitude.