# A New Method of Geological Modeling for the Hydrocarbon Secondary Migration Research
## 3 A Novel Object Stochastic Modeling Method
### Reservoir Physical Property Modeling  
Once the geological bodies have been properly modeled, the entire layer, comprising both the low-permeability background and the hierarchical reservoir bodies, undergoes thickness adjustments using practical structural data. The key structural deformation elements are extracted, taking into consideration well-seismic stratification, in order to capture the structural deformation characteristics specific to the targeted modeling area.  
There are two approaches to modeling faults: customization and automatic generation. In the customization method, fault lines or planes are customized to implement multi-fault modeling. Users can define the spatial distribution of fault traces as two-dimensional fault planes based on the structure contour map. These faults can then be incorporated as fluid flow passages or barriers in the property modeling process. Additionally, the customization method allows for fault modeling by physically separating the layers based on the fault polygon boundary derived from the structural contour. On the other hand, the automatic generation method involves importing seismic fault interpretation data to automatically generate faults in the model. This approach streamlines the fault modeling process and ensures consistency with the seismic data.  
Figure 6: Overview of stochastically generated mouth bar unit element (**A**), longitudinal section indicating inclined sediments (**B**), and the porosity model (**C**).  
To facilitate random fracture modeling based on regional fracture distribution, fracture templates and fracture model libraries are employed. This innovative approach to fracture gridding significantly enhances the efficiency and stability of numerical simulations conducted on fractured reservoirs. It enables the comprehensive characterization of the structural elements within the reservoir system, ensuring the accurate representation of fracture patterns and their impact on the fluid flow.  
The final step in constructing a 3D reservoir model is the extraction of the area of interest. For work areas with irregular polygon boundaries, it is possible to rotate them by specifying angles to reorient the I/J directions away from the traditional north-south or east-west orientations. The rotation angle can be adjusted by the user while viewing the real-time red-dotted boundary, ensuring the polygon fits appropriately based on the desired degree of rotation.  
Once sediment bodies are modeled in their respective locations, the distribution of sediment types is gridded, and the associations between the depositional texture and petrophysical properties are established. For numerical reservoir simulation and hydrocarbon migration, corner point gridding is employed, with vertical grids evenly dividing each zone based on the stratigraphic relief. When determining the grid resolution, it is essential to account for the size distribution of the reservoir bodies in order to capture the multiple scales of heterogeneity effectively.  
Porosity and permeability modeling entails assigning porosity values and defining key parameters such as maximum and minimum values, along with establishing an indirect permeability model. It is assumed that the logarithm of permeability for the same microfacies type is linearly correlated with the porosity, and appropriate parameter adjustments are made to achieve a reasonable distribution of permeability intervals. For overbank deposits in the floodplain, uniform impermeable values are assigned, as the focus lies on defining variations within the channel belt deposits. The resulting porosity and permeability model can be visualized along the I/J/K direction and represented as a fence diagram, respectively. The property model is utilized for the numerical reservoir simulation and hydrocarbon migration.