## 4 Discussion  
Each section in the combustion tube contained up to four core plugs. At least one representative sample from each CT section was selected for the analysis, including NMR, Rock-Eval pyrolysis, and gas porosimetry. We attempted to obtain the maximum knowledge on the reservoir and geochemical properties of the rock. Gas porosimetry was used to evaluate the porosity and permeability evolution of the rock. NMR relaxometry examined the saturation and porous space changes induced by combustion; pyrolysis analyzed the kerogen conversion in exposed rock species. NMR measured the change in total fluid volume of the sample and the spatial saturation using 1D NMR profiling. We used T\({}_{2}\) relaxation curves for illustrating the distribution of fluid-occupied pores inside the rock (Figure 13a,b). Images illustrate how the liquid phase was redistributed in the samples exposed at different temperatures. Sample #2 (located in Section 2.2) shows a decrease in the number of pores filled with the heavy components, and residual fluid relocation to larger pores, after the combustion. In the case of sample #12 (CT section--where the temperature reaches the maximum value), we observe the entire removal of mobile fluids and a small number of heavy components in the microporous region. Additionally, we utilized the developed NMR T\({}_{1}\)-T\({}_{2}\) interpretation scheme for registering the change in saturation and residual fluid types in the rock samples. In general, the total fluid volume is applicable for estimating the common saturation level change in rock and evaluate the influence of thermal exposure in the tube. Therefore, the disintegration of HC populations (fluid types) might be useful for modeling the thermal EOR processes and validation with experimental data. As explained earlier, in the Results section, we developed a simplified T\({}_{1}\)-T\({}_{2}\) interpretation map by reducing the number of fluid categories to bitumen and adsorbed oil, structural and adsorbed water, and mobile oil in IP. The summary of the samples investigated before and after CT is provided in Table 7. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Sample ID**} & \multirow{2}{*}{**Oil Field**} & \multirow{2}{*}{**S0**} & **S1** & **S2** & **S3** & **TOC** & **Tmax** \\ \cline{3-8}  & & & **mg HC/g Rocks** & **mg HC/g Rocks** & **mg HC/g Rocks** & **mg CO/g Rocks** & **wt.\%** & \({}^{\circ}\)C \\ \hline
1 & 1 & 0.05 & 0.13 & 4.56 & 0.70 & 1.55 & 425 \\
2 & 1 & 0.30 & 0.55 & 3.25 & 0.49 & 1.43 & 430 \\
3 & 1 & 0.04 & 0.1 & 0.44 & 0.38 & 1.41 & 457 \\
13 & 2 & 4.20 & 17.14 & 22.99 & 0.17 & 10.88 & 439 \\
15 & 2 & 2.20 & 2.69 & 26.42 & 0.24 & 5.30 & 434 \\
18 & 3 & 0.19 & 0.69 & 1.33 & 0.16 & 4.86 & 586 \\ \hline Avg. & & 1.16 & 3.55 & 9.83 & 0.36 & 4.24 & n/a \\ SD & & 1.70 & 6.73 & 11.66 & 0.21 & 3.71 & n/a \\ \hline \end{tabular}
\end{table} 
Table 6: Pyrolytic properties of samples after CT.  
We applied the Rock-Eval technique in two different modes: standard analysis of the single probe per sample and so-called 2D pyrolysis technique, where the entire plug was investigated using multiple drilled holes. Three samples were chosen for 2D pyrolysis: sample #10 (197 \({}^{\circ}\)C) and samples #12 (463 \({}^{\circ}\)C) and #15 (422 \({}^{\circ}\)C). Results demonstrated that the temperature of 463 \({}^{\circ}\)C is sufficient for the near-complete conversion of the organic matter in the consolidated core samples. Results of 2D pyrolysis showed an uneven distribution of organic matter by area in a cylindrical core sample #10.