# A New CO\({}_{2}\)-EOR Methods Screening Model Based on Interdependency Parameters
## 3 Results and Discussion
### Miscible CO\({}_{2}\)-EOR Screening Model  
The summary of simultaneous and individual combination screening models for miscible CO\({}_{2}\) is provided in Table 3. Simultaneous screening model A includes five parameters: MMP, temperature, depth, oil gravity, and oil viscosity. Although the grouping only concerns the limits or boundary of data values, to the best of our knowledge, the model may relate to mixture miscibility and the fluids' composition, where the mixture, in this case, stands for oil mixed with CO\({}_{2}\) within the reservoir during the injection. Indeed, the miscibility is sensitive to the pressure-related properties, i.e., MMP and depth, and also temperature. Furthermore, the composition of oil dictates the specific gravity and the viscosity, and affects the miscibility of CO\({}_{2}\) into the oil as well. Based on this, those five parameters were grouped into the corresponding model.  
\begin{table}
\begin{tabular}{l l} \hline \hline  & **Screening Model** \\ \hline \multicolumn{2}{l}{Simultaneous A:} \\ \(\bullet\) & MMP, psi \\ \(\bullet\) & Temperature, \({}^{\circ}\)F \\ \(\bullet\) & Depth, ft \\ \(\bullet\) & Oil Gravity, \({}^{\circ}\)API \\ \(\bullet\) & Oil Viscosity, cp \\ \hline \multicolumn{2}{l}{Simultaneous B:} \\ \(\bullet\) & Porosity, \% \\ \(\bullet\) & Permeability, md \\ \hline \multicolumn{2}{l}{} \\ \(\bullet\) & Minimum =17 \\ \(\bullet\) & Maximum =89 \\ \(\bullet\) & Mean =48.54 \\ \(\bullet\) & Standard Deviation =14.14 \\ \hline \multicolumn{2}{l}{} \\ \(\bullet\) & Minimum =9 \\ \(\bullet\) & Maximum =472 \\ \(\bullet\) & Mean =96.92 \\ \(\bullet\) & Standard Deviation =78.38 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Summary of the miscible CO\({}_{2}\)-EOR screening model.  
Figure 7: CO\({}_{2}\)-EOR simultaneous and individual combination screening model.  
The PCA method reduced the data dimensions to 2 PCs, explaining the total data diversity of 79.2%, as shown in Figure 8a. PC1 explains 59.1% and PC2 explains 20.1%. Figure 8b shows the magnitude of the eigenvectors for each PC. The \(T_{A}^{2}\) equation in Table 3 is simultaneous screening model A, a quadratic function of PC1 and PC2. The limit obtained was 11.13 at a confidence level of 99.5%, as shown in Figure 9. If the value of \(T_{A}^{2}\) is less than 11.13, the miscible CO\({}_{2}\)-EOR is the appropriate EOR method. The oil gravity and viscosity have a more significant effect on the value of \(T_{A}^{2}\).  
Simultaneous screening model B includes two screening parameters, namely porosity and permeability. As commonly known in petroleum literatures, a dimension combining permeability and porosity parameters represents the measure of volumetric flow capacity. In the same sense, the screening model B may also have similar physical meaning.  
A simultaneous screening model was developed using the MQC method. Figure 10a,b indicate that the screening boundary is in ellipse form, and the Hotelling \(T^{2}\) chart has an upper limit of 11.13 at a confidence level of 99.5%. The simultaneous screening model B is in the form of the \(T_{B}^{2}\) equation, a function of porosity and permeability. If the value of \(T_{B}^{2}\) is less than 11.13, it is suitable for the miscible CO\({}_{7}\)-EOR.  
Figure 8: (a) Scree plot and (b) eigenvectors of PCA for miscible CO\({}_{2}\)-EOR simultaneous screening model A.  
Figure 9: The Hotelling \(T^{2}\) chart for miscible CO\({}_{2}\)-EOR simultaneous screening model A.  
Oil saturation and net thickness parameters employ an individual screening model. Figure 11a shows the integration of box and swarm plots for oil saturation and Figure 11b for net thickness. The individual screening criteria of oil saturation have a minimum data value of 17%, as of that of Olive Field [19], and a maximum of 89%, as of that of Salt Creek Field [20]. Meanwhile, the minimum data of net thickness is 9 ft, as of that of Chester Field [21], and the maximum data is 472 ft, as of that of Citronelle Field [22].