## 5 Application
### Application on Shale from a Drill Well Profile  
The Zi208 well is located in the northeast of Zigong city, Sichuan province, with a longitude of 105.03\({}^{\circ}\) and a latitude of 29.25\({}^{\circ}\). A total of 145 shale samples were collected from a depth of 3890 m-3950 m in the Zi208 Well. The minimum, lower quartile, median, upper quartile, maximum, mean, and standard deviation of contents of major oxides, CaO/MgO, and WIG of the 145 samples are listed in Table 3.  
Given the statistical parameters of contents of SiO\({}_{2}\) and CaO (Table 3), the siliceous component (Type 1) and calcareous component (Type 6) can be determined from this profile. In order to better analyze the variation in classified types of samples, line graphs of SiO\({}_{2}\), CaO, CaO/MgO, WIG, and the classified type numbers of shale samples from the Zi208 well are plotted in Figure 3, along with their depth.  
In ca. 3890-3915 m of the Zi208 well, contents of SiO\({}_{2}\) are ca. 40-65%, contents of CaO are ca. 0-20%, and values of WIG are ca. 0-120, and their classified results are mostly type 3 (silicate component), with a small amount of type 4 (calcsilicate component).  
From the depth of ca. 3915 m to 3927 m, contents of SiO\({}_{2}\) and CaO and WIG exhibit clear variations, which corresponds to the classified type numbers ranging from 1 to 6. That is to say, all types of the classified results occur in this section of the profile.  
From the depth of ca. 3927 m to the end of the profile, the contents of SiO\({}_{2}\) decrease to a stable value, while CaO, CaO/MgO, and WIG increase to their stable values. These stable values correspond to the classified type number of 6 as calcareous component, which is consistent with the lithological name of limestone.  
\begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline
**Parameters** & **SiO\({}_{2}\)** & **Al\({}_{2}\)O\({}_{3}\)** & **TFe\({}_{2}\)O\({}_{3}\)** & **CaO** & **MgO** & **K\({}_{2}\)O** & **Na\({}_{2}\)O** & **TiO\({}_{2}\)** & **P\({}_{2}\)O\({}_{3}\)** & **CaO/MgO** & **WIG** \\ \hline Minimum value & 9.38 & 2.44 & 0.66 & 0.25 & 0.68 & 0.49 & 0.31 & 0.08 & 0.05 & 0.10 & 19.80 \\ Lower quartile value & 53.52 & 13.11 & 3.58 & 3.80 & 2.33 & 2.59 & 0.56 & 0.54 & 0.08 & 1.39 & 59.56 \\ Median value & 56.91 & 14.00 & 5.37 & 6.14 & 3.02 & 3.53 & 0.66 & 0.68 & 0.10 & 1.91 & 83.82 \\ Upper quartile value & 60.25 & 15.38 & 5.73 & 9.85 & 3.37 & 3.70 & 0.81 & 0.72 & 0.14 & 3.25 & 129.65 \\ Maximum value & 82.57 & 26.86 & 42.72 & 47.15 & 8.11 & 7.43 & 3.04 & 2.40 & 0.35 & 68.75 & 2587.22 \\ Mean value & 54.36 & 12.91 & 5.15 & 10.11 & 2.85 & 3.11 & 0.87 & 0.66 & 0.13 & 6.08 & 257.12 \\ Standard deviation value & 15.12 & 4.51 & 3.64 & 11.18 & 1.10 & 1.20 & 0.61 & 0.35 & 0.07 & 13.16 & 496.38 \\ \hline \hline \end{tabular} Note: The unit of major oxides is %.  
\end{table}
Table 3: Statistical parameters of shale samples from the Zi208 well in the southern Sichuan area.  
Figure 3: Line graphs of SiO\({}_{2}\) (**a**), CaO (**b**), CaO/MgO (**c**), WIG (**d**), and classified type numbers (**e**) of shale samples from the Zi208 well.  
In a word, shale samples from a profile can be classified based on the new proposed method and illustrated in a line graph with clear geochemical meaning.