## 3 Materials and Methods
### Two-Dimensional Basin Modeling of an Extruded Structural Section
#### 3.2.1 'Block' Definition and Subdivision  
For an extruded structural section with developed thrust faults, the 'Block' function in the Techink module of the Schlumberger PetroMod2017 software should be utilized. The stratigraphic section can be divided into several blocks, but the integrity of its structure is still maintained during the tectonic evolution process. The application of the 'Block' function allows for the simulation of each block, thereby enabling a holistic simulation of the entire stratigraphic section [4; 5].  
It can be seen (Figure 1d) that the post-salt and pre-salt layers have different structural deformation characteristics, with the N\({}_{\text{ij}}\) formation as the boundary in the section. The thrust faults in the pre-salt strata disappear in the gypsum-salt layer, except for the northern slope zone. According to the actual geological characteristics of the section, the steps of  
Figure 2: Major geological processes in basin modeling (after [PERSON] and [PERSON], 2009 [10]).  
establishing the model were as follows: the post-salt and pre-salt strata were divided into two systems. The pre-salt thrust faults were extended to the upper boundary of the gypsum-salt rock in the N1j formation, and then, each thrust block was divided into a 'Block' with the fault as the boundary. Based on the principle that one stratum can only appear once in a vertical grid line, the N-S section in this study was divided into 26 independent blocks (Figure 3).  
The compressional structural section of the foreland thrust belt is complex, and it is difficult to accurately restore this section of the geological history with the conventional stratigraphic backstripping technology in the basin modeling software [9]. The section of the geological history period was input into the software according to the above method, and a block model was established to simulate the geological evolution history of the complex compressional structure section, which provided a basis for the whole simulation of the tectonic evolution history, burial history, thermal evolution history, and hydrocarbon generation history. The discretization process entailed defining vertical grids and horizontal event lines. The width of each section was 54 km, and the section was subdivided into 540 grid cells with a resolution of 100 m/cell. The parameters in the Table 1 were input into each grid.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Formation**} & \multicolumn{2}{c}{**Deposition Age**} & \multicolumn{2}{c}{**Erosion/Hitaus**} & \multirow{2}{*}{**Ettoleum System**} & \multirow{2}{*}{**TOC**} & \multicolumn{2}{c}{**HI**} \\  & **From** & **To** & **To** & **From** & **To** & **Element** & **(\%)** & **(mg HC/g & **Kinetics** \\  & **(Ma)** & **(Ma)** & **(Ma)** & **(Ma)** & & & & & \\ \hline Q & 1.8 & 0 & & & Conglomerate (Typical) & Overburden rock & & & \\ N2k & 5.3 & 3 & 3 & 1.8 & Sandstone, Silsone, Shale & Overburden rock & & & \\ N1,2k & 12 & 5.3 & & & & Silstone, Shale & Overburden rock & & & \\ N1j & 23.03 & 12 & & & & Shale, Silstone, Gypsum & Seal rock & & & \\ E & 66 & 34 & 34 & 23.03 & Conglomerate, Sandstone & Reservoir rock & & & \\ K & 145 & 130 & 130 & 66 & Sandstone, Silstone & Reservoir rock & & & \\ J2k & 158 & 145 & & & & Shale (Typical) & & & \\  & 170 & 158 & & & & Shale (Organic-Rich, Typical) & & & \\  & 175.5 & 170 & & & Coal (Pure) & & & & \\  & 178 & 175.5 & & & Sandstone (Typical) & & & & \\ J1,7 & 178.5 & 178 & & & Coal (Pure), Shale (Typical) & & & & \\  & 182 & 178.5 & & & & & & & \\  & 188 & 182 & & & & & & & \\ J1,a & 201.3 & 188 & & & & & & & \\  & 203.5 & 201.3 & & & & & & \\ T & 210 & 203.5 & & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: General input parameters used for basin modeling. TOC = total organic carbon, HI = hydrogen index, C-mudstone = carbonaceous mudstone.  
Figure 3: Block subdivisions (numbered) in the present AA’ section of the eastern Kuqa Depression.