## 3 Mechanism of Molecular Deposition Film Technology  
### The Basic Concept and Composition of Molecular Deposition Films  
The process of preparing molecular deposition film technology is straightforward, requiring no expensive instruments or equipment. The assembly process reaches an equilibrium state and is not constrained by the shape or size of the substrate. In comparison to traditional self-assembled ultra-thin films and Langmuir-Blodgett (LB) supermembranes, molecular deposition films exhibit low surface energy, good chemical inertness, thermal stability, mechanical stability, and strong adhesion to the substrate without any toxicity or pollution. Both direct experimental evidence and theoretical support suggest that depositing single-layer and double-layer MD (molecular deposition) films on porous spherical carriers enables the emergence and establishment of molecular deposition film oil displacement technology.  
The technology of molecular deposition film for oil recovery primarily employs a water solution as the transmission medium, relying on strong electrostatic interactions between ions to facilitate its effectiveness. This method results in the formation of a robust single-molecule-layer ultra-thin film on the reservoir surface, which plays a critical role in reducing adhesion between the oil and the solid surface. By minimizing this adhesion, it significantly decreases both surface tension and oil-water interfacial tension, thereby promoting more efficient fluid movement. As concentration increases within the solution, it is noteworthy that there is no transition into a \"micelle\" state; instead, this technology maintains stability without altering the viscosity or fluidity ratio of the solution system. This characteristic ensures that flow properties remain consistent throughout various operational conditions, allowing for predictable performance during application. The process involves gradual formation of an ultra-thin film that advances toward its furthest point within the porous media. As this thin film develops and spreads across surfaces within the reservoir, it effectively strips away trapped oil molecules from their adhering sites. The action of water washing further enhances this effect by facilitating displacement; thus, oils are efficiently washed out from formations through hydraulic forces generated by flowing water.  
This mechanism not only improves overall water washing efficiency but also contributes to higher oil recovery rates than traditional methods. Enhanced interaction at interfaces allows better mobilization of residual hydrocarbons that would otherwise remain entrapped in rock pores. Furthermore, understanding how molecular deposition films interact with different geological formations can lead to optimized formulations tailored for specific reservoir conditions. Such advancements could result in improved strategies for enhanced oil recovery (EOR) techniques while ensuring minimal environmental impact associated with extraction processes.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Main Methods** & **Advantage** & **Disadvantages and Existing Problems** \\ \hline Chemical flooding (surfactant, composite flooding) & The theory is mature and widely applied. & The cost of surfactants is high, the investment in composite flooding is high, the risk is high, and there are many problems (scaling and blockage). \\ \hline Internal combustion explosion & Low cost, good economic benefits, and great potential. & There are certain safety risks that need to be addressed. \\ \hline \hline \end{tabular}
\end{table}
Table 1: _Cont._