## 2 Materials and Experiments  
### Materials  
#### 2.1.1 Oils  
The crude oil samples used in the experiments were sourced from the G Block of the Liaohe oilfield and the M Block of the Huabei oilfield, labeled as \"G\" and \"M\". Table 1 lists the reservoir conditions. The samples were subjected to dehydration and impurity removal. The dehydrated oil samples had a water content of less than 0.5%. Under degassing conditions at 50 \({}^{\circ}\)C, the viscosity of G crude oil is 15,000 mPa\(\cdot\)s, and the density is 0.947 g/cm\({}^{3}\). For M crude oil, the viscosity is 119 mPa\(\cdot\)s, and the density is 0.908 g/cm\({}^{3}\).  
According to petroleum classification standards, both oil samples were classified as heavy oil. The characteristics of crude oil were qualitatively characterized based on four components: saturate, aromatic, resin, and asphaltene (SARA) fractions [40]. We employed thin-layer chromatography-flame ionization detection (TLC-FID, Shandong Runyang Instrument Company, Sheng, China) to analyze the SARA fractions, and the steps were as follows:  
1. Take a certain amount of crude oil sample, dissolve it in chloroform, and prepare a solution with a concentration of 10-20 mg/mL.
2. Place the chromatography stick on the spotting plate. Using a micro-syringe (Shandong Runyang Instrument Company, Sheng, China), extract 1 uL of the sample solution and spot it at the end of the thin-layer chromatography stick in five separate rounds. Place the chromatography stick in a humidity chamber (saturated NaOH solution) and keep it for 10 min until the solvent evaporates.
3. Place the chromatography stick into the first chromatography jar (n-heptane). Wait for the solvent to migrate 8 cm on the chromatography stick and then remove the stick and place it in a humidity chamber. Allow it to stand for 10 min to allow the eluent to evaporate.
4. Place the chromatography stick into the second chromatography jar (n-heptane mixed with dichloromethane in a volume ratio of 1:1). Wait for the solvent to migrate 5 cm on the chromatography stick and then remove the stick and place it in a humidity chamber. Allow it to stand for 10 min to allow the eluent to evaporate.
5. Place the chromatography stick into the third chromatography jar (n-heptane mixed with isopentanol in a volume ratio of 9:1). Wait for the solvent to migrate 2.5 cm on the chromatography stick and then remove the stick and let it stand for 2 min to allow the eluent to evaporate.
6. Place the chromatography stick with separated samples into a hydrogen flame ionization scanner for scanning to obtain the chromatogram of the oil sample components.  
Table 2 lists the SARA information. As shown in Table 2, both oil samples had high resin and asphaltene content, classifying them as heavy oil. Oil sample M had higher saturate and aromatic content, indicating a relatively lower hydrogen-to-carbon ratio, closer to light oil.  
\begin{table}
\begin{tabular}{c c c} \hline
**Reservoir Conditions** & **G Block** & **M Block** \\ \hline Depth (m) & 1540\(\sim\)1610 & 760–900 \\ Thickness (m) & 34.1 & 18.0 \\ Permeability (mD) & 1037.0 & 344.8 \\ Pressure (MPa) & 16.10 & 7.58 \\ Temperature (\({}^{\circ}\)C) & 60.0 & 37.2 \\ Porosity (\%) & 17.5 & 22.1 \\ Oil saturation (\%) & 51.7 & 31.0 \\ \hline \end{tabular}
\end{table}
Table 1: The reservoir conditions.