Synergy of surface-treated nanoparticle and anionic-nonionic surfactant on stabilization of natural gas foams

Development of cost effective ultra-lightweight cellulose-based sound absorbing material over silica sol/natural fiber blended substrate

An Ultra-lightweight cellulose-based foam material (ULW-CFM) reinforced with silicasol was prepared by foam forming technology. The sodium dodecylbenzene sulfonate (SDBS) was a suitable foaming agent, creating stable bubbles for ULW-CFM with silicasol. The modulus of elasticity of ULW-CFM modified by silicasol was enhanced from 14.8 kPa to 83.32 kPa, and the yield strength was improved from 1.6 kPa to 4.36 kPa, respectively. The FTIR analysis indicated that the silicasol was deposited inside the material by SiOSi bonds and might has dehydration condensation reaction with cellulose. The thermostability of this material was also enhanced by silicasol. The weight loss of ULW-CFM with silicasol was less pronounced (60.36 %) than the one without (81.12 %). Owing to three dimensionally dispersed fiber structure, ultralightweight, high porosity, the sound absorption coefficient of ULW-CFM with silicasol reached 0.65 above 5000 Hz. Results show that ULW-CFM modified by silicasol has a promising application as a degradable sound absorbing material for dealing with noise.

Investigation of the Effect of Nanoparticle-Stabilized Foam on EOR: Nitrogen Foam and Methane Foam

In recent years, studies conducted on foam stabilization have focused on nanoparticles by generating strong adsorption at the interface to stabilize the foam under harsh reservoir conditions. Meanwhile, the selection of a gas source is also of great importance for foam performance. In this study, a mixed system of surfactants was selected, and the foamability and foam stability of nitrogen and methane were evaluated according to the improved jet method. After adding modified SiO₂ nanoparticles, the foam-related parameters were analyzed. The plugging abilities of the different foams were compared through core-flooding experiments, and the oil displacement effects of the different foams were compared through microfluidic experiments. The results show that the amphoteric surfactant betaine has an excellent synergistic effect on the anionic surfactant SDS. The methane foam produced using the jet method has a larger initial volume than the nitrogen foam, but its stability is poor. The half-life of the nitrogen foam is about two times that of the methane foam. After adding 1.0 wt % SiO₂ nanoparticles to the surfactant solution, the viscosity and stability of the formed foam improve. However, the maximum viscosity of the surfactant nanoparticle foam (surfactant-NP foam) is 53 mPa·s higher than that of the surfactant foam. In the core-flooding experiment, the plugging performance of the methane foam was worse than that of the nitrogen foam, and in the microfluidic experiment, the oil displacement abilities of the methane foam and the nitrogen foam were similar. The plugging performance and the oil displacement effect of the foam are greatly improved by adding nanoparticles. The surfactant-NP foam flooding has a better oil displacement effect and can enhance the recovery factor by more than 30%. Under actual high-pressure reservoir conditions, although the stability of the methane foam is weaker than that of the nitrogen foam, some methane may be dissolved in the crude oil to decrease the viscosity after the foam collapses, which leads to the methane foam being the preferred method in oilfields.