Effect of Montmorillonite on the Properties of Organic-Inorganic Composite Cross-Linked Polyacrylamide Gel System

The organic-inorganic composite cross-linking technology can effectively improve the temperature resistance of polyacrylamide gel systems. However, the effect of adding montmorillonite to the system and its impact on performance has not been studied. By using visual code method, differential scanning calorimetry (DSC), and other methods, the effects of montmorillonite on the temperature resistance, gelation properties, and microstructure of the organic-inorganic composite cross-linking polyacrylamide gel system were investigated. The microstructure of the gel system was analyzed by infrared spectroscopy and scanning electron microscopy (SEM). The results showed that the organic-inorganic composite cross-linking gel with different mass fractions of montmorillonite can effectively form a gel, which covers the three-dimensional network structure and does not damage the original spherical-tree structure. By changing the dosage of montmorillonite, it is found that the strength of the gel system is not only related to the density of the three-dimensional network structure, but also related to the composition of the network structure. The gelation time is approximately 21.0–22.0 h, with strength ranging from H to F level. The gel does not break down after high-temperature aging at 140 ℃ for 120 days, indicating good long-term thermal stability. The peak temperature of the differential scanning calorimetry increases with the increase of montmorillonite mass fraction. When the montmorillonite mass fraction is 2.5%, the peak temperature can reach 181 ℃. Adding montmorillonite can improve the performance of the organic-inorganic composite cross-linking polyacrylamide gel system, and can be used to prepare medium-strength gel systems for high-temperature oil and gas field profile control and water shut-off to further enhance the recovery rate.