## 5 Discussion  
This study reveals the complex sedimentary architecture of the Chang 8 oil group in the Luo 1 well area of the Jiyuan Oilfield, which has important implications for oil reservoir \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{3}{*}{**Layer**} & \multirow{3}{*}{**Injection and Production**} & \multicolumn{6}{c}{**Injection-Production Does Not Correspond to the Situation**} \\ \cline{3-10}  & & \multicolumn{2}{c}{**Injection Without**} & \multicolumn{2}{c}{**No Injection with Production**} & \multicolumn{2}{c}{**No Injection Without**} \\  & & \multicolumn{2}{c}{**Production**} & \multicolumn{2}{c}{**Production**} & \multicolumn{2}{c}{**Production**} \\  & **Well** & **Proportion** & **Well** & **Proportion** & **Well** & **Proportion** & **Well** & **Proportion** \\  & **Numbers** & **(\%)** & **Numbers** & **(\%)** & **Numbers** & **(\%)** & **Numbers** & **(\%)** \\ \hline Chang\({}_{8}\)\({}^{2,2+2}\) & 3 & 4.4 & 0 & 0 & 3 & 4.4 & 62 & 91.2 \\ Chang\({}_{8}\)\({}^{2,2+1}\) & 29 & 42.6 & 0 & 0 & 18 & 26.5 & 21 & 30.9 \\ Chang\({}_{8}\)\({}^{2,2+2}\) & 21 & 30.9 & 0 & 0 & 15 & 22.1 & 32 & 47 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Injection–production correspondence in the study area. Figure 8: Dynamic verification analysis diagram of D238-64 well group. development. The reservoir, characterized by ultra-low permeability (0.84 mD), highlights the need to understand the internal architecture of sand bodies and their heterogeneity for optimizing extraction methods. The study's findings on ultra-low-permeability reservoir architecture provide a critical foundation for optimizing oil recovery strategies. By enhancing our understanding of sand body distribution and connectivity, this research can significantly improve reservoir management practices in China and other Asian countries facing similar geological challenges. Tailored development plans based on these insights can lead to more efficient exploitation of remaining oil resources, thereby contributing to regional energy security. From a socio-environmental standpoint, the enhanced recovery efficiency proposed by this study could reduce the environmental footprint of oil extraction by maximizing production from existing wells. This innovation not only offers economic benefits but also aligns with sustainability goals. Chinese environmental agencies have increasingly emphasized green development, and this research supports that agenda by promoting more sustainable resource utilization methods. To strengthen the validation of our results, we compare them with previous studies on deltaic depositional systems. Unlike earlier works that often lacked detailed architectural configuration analysis, our study provides new insights into the scale of distriburNotably, subaqueous distributary channels are relatively small in scale, typically less than 300 m wide and spanning no more than two well spacings. To delineate delta-front reservoir architectural boundaries, we adopted a \"vertical phasing and lateral boundary delineation\" approach. Five types of markers were established, enabling detailed tracking of profiles and the identification of single architectural sand body boundaries. This method facilitated a comprehensive architectural analysis of contiguous single sand bodies within the study area. Two major architectural patterns--isolated and stacked--were summarized for the study area, further subdivided into seven stacking styles. In primary reservoir layers, lateral amalgamation patterns dominate (77.15%), while vertical stacking patterns are most common in vertical sections (74.63%). Non-primary reservoir layers, however, are primarily characterized by lateral isolation and vertical separation. These findings indicate that ultra-low-permeability reservoir development is mainly controlled by the scale of individual distributary channels.