## 4 Results  
To validate the results of reservoir architectural analysis and better guide the later stages of oilfield development, a comprehensive evaluation was conducted. This included analyzing perforation intervals layer by layer, assessing the effectiveness of tracer injections, and examining oil and water production curves for injection-production correspondence. These findings were further corroborated by integrating cross-sectional facies maps to verify the accuracy of sand body architectural interpretations [46; 47; 48; 49; 50].  
Taking the single-layer well group of Chang 82\({}^{\text{-}}\)2-21 in the study area, represented by well D238-64 (Figure 8), as an example, D238-64 is a tracer injection well. The monitoring wells associated with this group are D238-65, D238-63, DJ237-643, DJ237-644, DJ239-641, and DJ239-642, with respective distances from D238-64 of 303 m, 274 m, 253 m, 129 m, 194 m, and 208 m. Tracer injection commenced 29 June 2019, using SZJ-2 as the tracer, with a total injection quantity of 5.0 kg.  
The tracer monitoring results indicate that out of the six monitoring wells in the D238-64 well group, two detected the tracer. This confirms that there is a connectivity relationship within the single sand body between the tracer injection well and the monitoring wells in this layer. From the tracer production concentration curve (Figure 8c), the single and sharp peak suggests significant vertical heterogeneity within the reservoir of the well group. The injection well and the two tracer-detected wells are located within the same channel unit.  
In terms of well spacing, the monitoring wells closer to the injection well detected the tracer earlier, while those farther away may have been blocked by flow barriers within the reservoir. Regarding tracer detection direction, well DJ237-644 detected the tracer earlier than DJ239-641, with the former having higher permeability than the latter. This indicates that medium- to high-permeability zones serve as the primary pathways for tracer migration. Well D238-63, although within the same channel as the injection well, did not detect the tracer because it was not perforated in this layer [51; 52; 53; 54; 55].  
In Figure 8d, the injection volume for well D238-64 began to increase in October 2019. Correspondingly, the daily liquid production and water cut for well D239-641 also increased. Subsequently, as the injection volume decreased, the water cut also declined in May 2020, demonstrating a strong response and confirming that the two wells belong to the same channel. Wells DJ239-641, DJ237-644, and D238-64 are all classified as poor oil  
Figure 7: Statistical analysis of single underwater distributary channel sand body dimensions.  
layers or oil layers, with natural gamma curves showing a box shape, placing them in the same channel. However, wells D237-643 and D239-642, classified as weakly water-flooded layers, are not effectively connected to the injection well D238-64 due to differences in oil and gas characteristics (Figure 8f), indicating they belong to different channels with poor connectivity. This architectural interpretation aligns well with the tracer detection results and production curves, thereby validating the accuracy of the architectural analysis.  
According to the statistics, the study area contains 22 water injection wells corresponding to 58 production wells. Among them, 21 wells are effective, and 13 wells have been converted to injection wells. Within single distributary channels, injection-production connectivity is good, whereas connectivity between different distributary channels is poor, with only 25.97% of channels being connected (Table 2). This indicates that the development of ultra-low-permeability reservoirs is primarily controlled by the scale of individual distributary channels. These findings provide a reference for the exploration of remaining oil and the optimization of development strategies in the Luo 1 well area.