## 3 Results
### Comparison between Laboratory Measurements and Tomographic Images Calculations
However, even without taking into account a large proportion of poral phase, results from the two methods are similar and consistent, which leads us to conclude that large pores are more likely to control rock parameters on large scale, while small pores may control interactions between parameters at small scale. Groups formed inside each rock family overlap, from laboratory measurements and XRMT calculations. Indeed, in the Normandie set, N03/N05 couple has been constituted from both methods. This group presents high porosities and low electrical parameters from laboratory measurements, while relatively low permeabilities from XRMT. It also has a high proportion of small pores, which do not participate to the main flow, and is consistent with relatively low percolating volume \(PV\) and \(\frac{S}{V}\), while high \(f\). Then, N02/N09 and N04/N08 formed two groups that can be gathered in one. These samples have relatively low porosities and high electrical factors from laboratory measurements, while high permeabilities from XRMT. They count a relatively low proportion of pores smaller than 10 \(\upmu\)m, which comes with a high \(PV\) and \(\frac{S}{V}\), while a low \(f\). In Figure 9, pore diameters distributions from both laboratory measurements and XRMT calculations are displayed on a similar graph. Data from centrifuge are more precise for pores smaller than 30 \(\upmu\)m because large pores are more likely to empty before the experiment starts. Concerning XRMT calculations, only pores larger than a pixel are taken into account for calculations, then data is more precise for pores larger than two pixels, i.e., 24 \(\upmu\)m. Therefore, in Figure 9, classes up to 30 \(\upmu\)m are data from centrifuge and classes up to 30 \(\upmu\)m are data from XRMT calculations. The previous mentioned groups are consistent with whatever the method used. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Samples** & \(f\) & **Samples** & \(f\) & **Samples** & \(f\) \\ \hline N02 & 0.19 & E02 & 0.39 & L01 & 0.95 \\ N03 & 0.98 & E04 & 0.34 & L04 & 0.17 \\ N04 & 0.11 & E05 & 0.23 & L08 & 0.42 \\ N05 & 0.88 & E08 & 0.40 & & \\ N08 & 0.37 & & & & \\ N09 & 0.43 & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Estimation of the constrictivity \(f\) from electrical tortuosity \(\tau_{e}\) and hydraulic tortuosity \(\tau_{h}\). Figure 9: Pore diameters distributions from laboratory and XRMT calculations for Normandie rock type. Distribution from centrifugation and sphere diameters analysis is displayed on the left, while distribution from centrifugation and chord lengths analyses is shown on the right. For Euville rocks, as previously established, all samples have very similar properties, whatever the method used. While two couples have been distinguished from laboratory measurements, there is no particular couples constituted from XRMT calculations. Despite E02/E04 always have higher porosities and lower electrical factors than E05/E08, other parameters do not present such variations. Also, pore diameters distribution are pretty much the same, as it can be seen in Figure 10. We can thus conclude that Euville samples have similar properties whatever the technique and scale analyses, indicating that they can be considered to be a Representative Elementary Volume (REV), and can act as analogous to limestone rock reservoirs. Concerning Lexos samples, two groups have been distinguished from images analysis due to the very important proportion of pores diameters smaller than 12 \(\upmu\)m in L03 and L07, which induces an impervious barrier to the fluid flow. Two groups have also been formed from the petrophysical analysis, where L01, L04 and L08 have a majority of intermediate size pores and L03/L07 have a majority of pores smaller than 1.3 \(\upmu\)m, as displayed in Figure 11. Lexos samples have a majority of pore diameters around 12 \(\upmu\)m (Figure 4) and should have equivalent results from laboratory and XRMT.