Development and Performance Evaluation of a Nanoparticle-Enhanced Foam Drainage System for Shale Gas Wells

In the later stages of shale gas well development, liquid accumulation in the wellbore became a significant problem. It restricts gas production and sometimes even causes well shutdowns due to water flooding. Foam drainage and gas recovery technology is an economical and convenient deliquification method, yet its stability has remained a challenge. Developing a highly efficient and stable foam drainage system for complex shale gas well environments is of great significance for enhancing shale gas production. This study focused on developing a nanoparticle-enhanced foam drainage system (TK5). KH-550 modified nano-SiO₂ (K₅5) was utilized as a stabilizer, and sodium dodecyl sulfate/LAB-35 were employed as foaming agents. The research methods included characterizing K₅5 nanoparticles through FT-IR, transmission electron microscopy, and Zeta potential analyses. The corresponding foam system was optimized under various conditions, such as high temperature, salinity, and condensate oil content. The performance of the system was investigated, and the stability mechanism of TK5 was explored through coarsening behavior studies, surface tension measurements, and molecular dynamics simulations. The main conclusions of this research indicated that the TK5 system exhibited an excellent performance. It could resist temperatures up to 90 °C, salinity of 75,000 mg/L, and 25% condensate oil. Compared with unmodified nano-SiO₂, K₅5 showed a 60% reduction in surface hydroxyl content, which led to significantly less nanoparticle aggregation in solution. K₅5 effectively retarded foam coarsening and liquid drainage, enhancing the overall stability of the foam. The nanoparticles in TK5 adsorbed at the gas-liquid interface, reducing surface energy and lowering surface tension, which optimized the particle arrangement at the interface and delayed foam drainage. These results suggested that TK5 can provide efficient and stable foam-assisted gas recovery, making it suitable for complex shale gas well environments.