## 7 Conclusions  
The key issue currently limiting the renovation and utilization of old caverns with butted wells is the lack of understanding of their complete morphology. To address this, a seismic forward simulation method was employed, incorporating the characteristics of real salt cavity morphology and actual seismic acquisition parameters. A theoretical geological model was established to investigate the seismic response law of the BWSC model under five morphological factors including cavity spacing, cavity diameter, cavity height, sediment height and horizontal connection channel height in this paper. The main findings are as follows:  
1. The top surface of the salt cavity exhibits a distinctive reflection feature characterized by \"two peaks sandwiching a strong valley\". Notably, the cavity's top surface consistently aligns with the position of this strong reflection trough, remaining unaffected by other cavity shape factors. This alignment serves as a crucial indicator for identifying the location of the cavity roof using seismic data. Additionally, the waveform width of the strong valley reflection at the cavity top demonstrates an amplification effect relative to the cavity diameter, where the amplification factor is inversely proportional to the salt cavity diameter. 2. The top surface of the insoluble residual in the cavity exhibits a wave peak reflection pattern characterized by an \"upward-opening arc\". This peak position presents a notable downward offset relative to the top surface of the residual, which diminishes as the proportion of residual height to overall cavity height increases. Importantly, the wave peak reflection of the residual's top surface consistently manifests as the first peak beneath the two peak reflections of the cavity's top surface, serving as an important identification for the actual location of the residual's top surface. 3. The top and bottom surface of the horizontal connection channel present independent reflection characteristics: the top surface displays a \"one peak and one valley\" pattern, while the bottom surface shows a \"one valley and one peak\" feature. These characteristics are primarily influenced by cavity spacing and connection channel height. The troughs from the top surface closely align with the top boundary of the channel, with their positions being largely consistent, while the peaks reflection from the bottom surface exhibits a downward shift with the changing of the channel height. The position of the trough reflection from the top surface of the channel serves as a vital indicator for pinpointing the true location of the channel's top boundary. By integrating this information with the actual wellbore trajectory, the channel height can be basically determined. 4. The single-sided brine cavity exhibits a distinctive circular reflection feature, mainly composed of wave peaks and valleys from the top surfaces of both the cavity and the residue. In the case of the two cavities from the butted well, this pattern manifests as a double ring waveform resembling eyeglasses. The prominence of the circular feature increases with the cavity's diameter or spacing, and in this circular waveform, the top surface of the residue is always located in its upper half. This phenomenon can also serve as an indicator for identifying the position of the residue's top surface. In summary, seismic identification is considered the most effective method for studying the complete morphology of butted well salt cavities, especially when direct measurements are not feasible. This research has simplified the BWSC model and the density of formation and residual, offering valuable insights for the 3D seismic identification of real old cavity morphology. However, it is important to acknowledge the complexity of real strata, salt cavity morphologies, and sediment occurrence states, which can pose challenges for identifying the bottom and periphery of the cavity.