## 5 Discussion
### Maturity Assessment of Crude Oils
As discussed above, the equivalent vitrinite reflectance (Rc) (with average values varying from 1.48% to 1.58%) of crude oils derived from light hydrocarbons, diamondoids, and aromatics all indicate that the crude oils in this study are at a high maturity stage. From Figure 6, according to the correlation plot of DNR and MDR, it can also be seen \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Well** & **MCH** & **nC\({}_{7}\)** & **EDMCP** & **ICH** & **IMCH** & **I** & **H** & **K1** & **nC\({}_{7}\)/MCH** & **TOL/nC\({}_{7}\)** \\ \hline S1-3 & 31.69 & 55.76 & 12.55 & 21.43 & 32.22 & 2.40 & 41.19 & 1.03 & 1.76 & 0.35 \\ S1-18 & 29.21 & 56.80 & 13.98 & 16.85 & 29.77 & 2.53 & 39.98 & 1.04 & 1.94 & 0.29 \\ S1-7 & 29.99 & 56.29 & 13.72 & 18.64 & 30.50 & 2.42 & 40.20 & 1.03 & 1.88 & 0.31 \\ S1-20 & 31.33 & 54.87 & 13.81 & 19.28 & 31.89 & 2.34 & 39.34 & 1.03 & 1.75 & 0.33 \\ S1-1 & 31.18 & 54.56 & 14.26 & 18.34 & 31.76 & 2.32 & 38.71 & 1.03 & 1.75 & 0.31 \\ S1-5 & 32.30 & 54.16 & 13.54 & 20.82 & 32.87 & 2.26 & 39.38 & 1.01 & 1.68 & 0.30 \\ S1-11 & 28.68 & 57.47 & 13.86 & 17.18 & 29.21 & 2.48 & 40.84 & 1.02 & 2.00 & 0.24 \\ S1-14 & 33.72 & 51.15 & 15.14 & 22.53 & 34.35 & 2.02 & 36.56 & 1.03 & 1.52 & 0.20 \\ S1-15 & 31.05 & 54.91 & 14.04 & 18.68 & 31.61 & 2.30 & 39.32 & 1.01 & 1.77 & 0.27 \\ S1-16 & 30.91 & 55.12 & 13.98 & 17.96 & 31.46 & 2.37 & 39.16 & 1.01 & 1.78 & 0.26 \\ S1-9 & 31.91 & 54.73 & 13.36 & 20.49 & 32.45 & 2.35 & 39.54 & 1.02 & 1.72 & 0.35 \\ SP3 & 32.53 & 53.18 & 14.29 & 19.40 & 33.16 & 2.28 & 37.55 & 1.03 & 1.63 & 0.34 \\ S1-1 & 30.96 & 54.97 & 14.07 & 20.26 & 31.49 & 2.09 & 39.97 & 1.01 & 1.78 & 0.22 \\ \hline \end{tabular} Note: MCH = methylcyclohexane; EMDCP = (1,1-DMCP + 1 cis-DMCP + 113-DMCP + 1t2-DMCP) [54]; nC\({}_{7}\) = n-heptane; Tol = toluene; DMCP = dimethylcyclohexane; LRT(\({}_{7}\)) = CH \({}_{7}\) = CH \({}_{7}\) = CH\({}_{8}\) = 100% (CH+MCP + nC\({}_{6}\)); IMCH(\({}_{7}\)) = MCH \({}_{7}\) \(\times\) 100%/(MCH + T-1, 3-DMCP +1, 3-DMCP +1, 3-DMCP + nC\({}_{7}\)); Isoheptane (a = + 3) + MH/(1 cis + 1t2)-DMCP, H: heptane value = (nC\({}_{7}\) \(\times\) 100)/(CH + 2.MH + 2,3-DMCP + 1,1-DMCP + 3-MH + 1 cis-DMCP + 113-DMCP + 112 DMCP + nC7 + MCH) [49]; K1 = (2-MH + 2,3-DMP)/(3-MH + 2,4-DMP) [39].  
\end{table} 
Table 4: Parameters derived from LHs of the studied oil samples. Figure 5: The cross-plot of the light hydrocarbon parameter heptane ratio versus the isoheptane ratio for the studied oil (after [PERSON] [49] and [PERSON] [50]). that they present a remarkable linear correlation (y = 3.59x \(-\) 12.84, R\({}^{2}\) = 0.96), while oils in the southwestern region of the F1 area (S1-11-S1-16) are slightly more mature than oils in the northeastern region of the F1 and the well, SL1, far from the No. 1 main fault zone. Moreover, the two maturity grades (1.06-1.25% and 1.36-1.67%) of the oil samples calculated from the aromatic compounds indicate the presence of at least two clearly differentiated stages of hydrocarbon charge, with the late-stage charge dominating, which is consistent with previous insights derived from fluid inclusion studies and basin modeling [15,28].