## 2 Materials and Techniques
### Experimental Procedures
#### 2.3.2 NMR and MICP Measurements  
The NMR method primarily involves scanning the core for T\({}_{2}\) spectra to detect hydrogen nuclei in the core, thereby determining the volume of fluid within the core. The specific experimental procedure follows the standards of the Chinese petroleum and natural gas industry: Chinese oil and natural gas industry standard \"SY/T 6490-2023 Specification for laboratory measurement of NMR parameter of rock samples [46]\". The MICP method involves applying pressure to liquid mercury, allowing it to overcome capillary resistance and enter the pores. Then, based on the fraction of pore volume \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \begin{tabular}{c} **Well** \\ **Number** \\ \end{tabular} & **Samples** & **Length (mm)** & **Diameter (mm)** & **Volume (mL)** & \begin{tabular}{c} **Helium** \\ **Porosity (\%)** \\ \end{tabular} & \begin{tabular}{c} **Permeability** \\ **(mD)** \\ \end{tabular} & **Lithology** \\ \hline \multirow{3}{*}{S1} & 1 & 87.01 & 24.40 & 40.69 & 14.98 & 1.06 & Sandstone \\ \cline{2-7}  & 2 & 71.52 & 24.50 & 33.72 & 13.74 & 3.06 & \multirow{3}{*}{\begin{tabular}{c} Conglomerate \\ sandstones \\ \end{tabular} } \\  & 3 & 57.78 & 24.55 & 27.35 & 14.61 & 8.20 & \\  & 4 & 53.14 & 24.45 & 24.95 & 14.81 & 5.86 & \\ \hline \multirow{3}{*}{S2} & 5 & 72.10 & 24.55 & 34.13 & 13.90 & 1.83 & \multirow{3}{*}{\begin{tabular}{c} Sandstone \\ \end{tabular} } \\  & 6 & 72.10 & 24.50 & 33.99 & 13.66 & 1.20 & \\ \hline \multirow{3}{*}{S3} & 7 & 72.53 & 24.52 & 34.25 & 15.75 & 2.37 & \multirow{3}{*}{\
\begin{tabular}{c} Sandstone \\ \end{tabular} } \\  & 8 & 67.10 & 24.45 & 31.50 & 15.88 & 1.29 & \\ \hline \multirow{3}{*}{H1} & 1 & 56.30 & 25.11 & 27.88 & 5.49 & 0.0471 & \multirow{3}{*}{
\begin{tabular}{c} Shale \\ \end{tabular} } \\  & 2 & 53.31 & 25.11 & 26.40 & 6.16 & 0.0371 & \\ \hline \multirow{3}{*}{H2} & 3 & 40.49 & 25.40 & 20.52 & 6.51 & 0.0065 & \\  & 4 & 39.94 & 25.47 & 20.35 & 6.04 & 0.0141 & \\ \hline \multirow{3}{*}{H3} & 5 & 40.49 & 25.43 & 20.57 & 11.02 & 0.0753 & \\  & 6 & 41.83 & 25.37 & 21.15 & 6.97 & 0.0344 & \\ \hline \multirow{3}{*}{H4} & 7 & 32.50 & 25.40 & 16.47 & 6.51 & 0.0399 & \\  & 8 & 32.80 & 25.40 & 16.62 & 5.91 & 0.0177 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Basic physical properties of samples. filled with mercury and the corresponding pressure, the pore size distribution of the core is obtained. The specific experimental procedure follows the Chinese National Standard \"GB/T 29171-2023 Rock capillary pressure measurement [47]\". The primary signals detected using NMR in the rock core were mainly water signals (with shales containing kerogen, asphaltene, and structural water). The maximum mercury intrusion pressure for the MICP could reach up to 200 MPa. The pore throat distribution obtained from MICP and the T\({}_{2}\) relaxation time distribution from the NMR test can be further analyzed to examine the fluid distribution in different pore sizes of the rock core. The specific experimental steps are shown in Figure 3.  
All samples underwent an extensive cleaning process using Dean-Stark apparatus. After cleaning, the core samples were dried at 80 \({}^{\circ}\)C for 72 h. The status of the heated samples was ascertained using the T\({}_{2}\) relaxation time distribution spectrum. If the T\({}_{2}\) signal intensity is high, an additional 72 h of vacuum heating is required until the T\({}_{2}\) signal intensity becomes constant. After confirming that the rock core is thoroughly cleaned, a piece is cut for the MICP experiment with a thickness of 2 cm. The experimental maximum injection pressure is selected based on the lithology. The compressive strength of tight sandstone is usually higher than that of shale. Therefore, we have set the maximum injection pressure for tight sandstone and shale at 200 MPa and 100 MPa, respectively.