## 4 Results
### Basin Modeling Results  
#### 4.4.1 Hydrocarbon Generation and Accumulation History  
Vitrinite reflectance (Ro) serves as a measure of the maturity of the source rocks. The Easy% Ro Model is the most widely used model in the study of paleo-temperature. In this  
Figure 11: PCA score plot of the five principal components from the source rock extracts (**A**,**B**), reservoir oil extracts (**C**), inclusion oil extracts (**D**), and the cross plot of PC1 and PC5 (**E**), reflecting the similarity between the Jurassic source rocks and the J1\(y\) oils, Triassic source rocks, and the J1\(a\) oils. Mix sources are seen among all the oils. See Table 1 for sample information. study, the thermal histories of the source rocks from section AA\({}^{\prime}\) were modeled based on the Easy% Ro routine, which is applicable in the range of 0.3-4.5%. The modeling results have a good fit to the measured Ro values (Figure 12). Figures 13 and 14 show the results of the hydrocarbon generation, migration, and accumulation modeling of the cross-section AA\({}^{\prime}\) at spatial and temporal scales. The results are shown as follows. (1) At 23.3 Ma, both the Triassic source rocks and Jurassic source rocks were low-mature with Ro values of 0.55-0.8% and generated a small amount of early oil (Figures 13A and 14A). (2) At 12 Ma, the uplift of the southern Tianshan Mountains resulted in the differential burial of strata from north to south, with the result that the source rocks in the Sag Belt matured rapidly at this stage (Figure 13B). The Triassic source rocks and a minor amount of the Jurassic source rocks in the Sag Belt became highly mature, with the generation of a quantity of wet gas (1.3-2.0% Ro), while most of the Jurassic source rocks in the Sag Belt became mature, with the generation of a large amount of late oil (1.0-1.3% Ro) (Figures 13B and 14B). At this time, most of the source rocks in the Slope Belt entered the oil generation stage, with the mature oil (0.7-1.0% Ro) generated from the Triassic source rocks and the low-mature oil (0.55-0.7% Ro) generated from the Jurassic source rocks. (3) At 5.3 Ma, the source rocks in the Slope Belt entered the main oil generation stage (0.7-1.3% Ro), and most of the source rocks of the Sag Belt entered the wet gas generation stage (1.3-2.0% Ro, Figure 13C). Large amounts of light oil and gas migrated into the Jurassic reservoirs via unconformities and faults, forming significant accumulations in the zones of trap development (Figure 14C). (4) At 3 Ma, with the deposition of the extremely thick Kuqa Formation (N\({}_{2}\)_k_), the strata were buried rapidly to depths ranging from 4000 m to 8000 m. The source rocks reached the dry gas, wet gas, and late oil generation stage in the Sag Belt through to the Slope Belt, respectively (Figure 13D). Gas generated from the Sag Belt and Slope Belt and the oil generated from the Slope Belt and Anticline Belt co-charged the Jurassic reservoirs (Figure 14D). (5) At present, the transformation ratio (TR) of the Jurassic source rocks reaches 70% in the Sag Belt, 20% to 40% in the Slope Belt, and only 10% in the Anticline Belt (Figure 15). For the Triassic source rocks, the TR values reach 90% near or in the Sag Belt, 30% to 60% in the Slope Belt, and 20% in the Anticline Belt (Figure 15). Figure 12: Calibration of the thermal history model, showing that the measured Ro and calculated Ro values in YN–2 well (**A**) and DB–5 well (**B**) from the AA\({}^{\prime}\) section across the Dibei Gas Field are in good agreement. Figure 13: Thermal maturity evolution of the J\({}_{2}\)\(k_{2}\), J\({}_{1}\)\(y\), T\({}_{3}\)\(t\), and T\({}_{3}\)\(h\) source rocks in the AA\({}^{\prime}\) section at five geological periods in the northern Kuqa Foreland Basin. (**A**) 23.3 Ma; (**B**) 12 Ma; (**C**) 5.3 Ma; (**D**) 3 Ma; (**E**) Present. Figure 14: Hydrocarbon migration pathways and hydrocarbon saturation in the AA\({}^{\prime}\) section at five geological periods in the northern Kuqa Foreland Basin.