Bulk and bubble-scale experimental studies of influence of nanoparticles on foam stability

Influence of silicon oxide(SiO_2) and aluminum oxide(Al_2O_3) nanoparticles on the stability of nanoparticles and sodium dodecyl sulfate(SDS) mixed solution foams was studied at bulk and bubble-scale. Foam apparent viscosity was also determined in Hele-Shaw cell In order to investigate the foam performance at static and dynamic conditions. Results show that the maximum adsorption of surfactant on the nanoparticles occurs at 3 wt% surfactant concentration. Foam stability increases while the foamability decreases with the increasing nanoparticle concentration. However, optimum nanoparticle concentration corresponding to maximum foam stability was obtained at 1.0 wt% nanoparticle concentration for the hydrophilic SiO_2/SDS and Al_2O_3/SDS foams. Foam performance was enhanced with increasing nanoparticles hydrophobicity. Air-foams were generally more stable than CO_2 foams.Foam apparent viscosity increased in the presence of nanoparticles from 20.34 mPa·s to 84.84 mPa·s while the film thickness increased from 27.5 μm to 136 μm. This study suggests that the static and dynamic stability of conventional foams could be improved with addition of appropriate concentration of nanoparticles into the surfactant solution. The nanoparticles improve foam stability by their adsorption and aggregation at the foam lamellae to increase film thickness and dilational viscoelasticity. This prevents liquid drainage and film thinning and improves foam stability both at the bulk and bubble scale.

Characterization of lauryl betaine foam in the Hele-Shaw cell at high foam qualities(80%-98%)

Lauryl betaine(LB)as an amphoteric surfactant carries both positive and negative charges and should be able to generate stable foam through electrostatic interaction with nanoparticles and co-surfactants.However,no previous attempts have been made to investigate the influence of nanoparticles and other co-surfactants on the stability and apparent viscosity of LBstabilized foam.In this study,a thorough investigation on the influence of silicon dioxide(SiO2)nanoparticles,alpha olefin sulfonate(AOS)and sodium dodecyl sulfate(SDS),on foam stability and apparent viscosity was carried out.The experiments were conducted with the 2D Hele-Shaw cell at high foam qualities(80%-98%).Influence of AOS on the interaction between the LB foam and oil was also investigated.Results showed that the SiO2-LB foam apparent viscosity decreased with increasing surfactant concentration from 0.1 wt%to 0.3 wt%.0.1 wt%SiO2 was the optimum concentration and increased the 0.1 wt%LB foam stability by 108.65%at 96%foam quality.In the presence of co-surfactants,the most stable foam,with the highest apparent viscosity,was generated by AOS/LB solution at a ratio of 9:1.The emulsified crude oil did not imbibe into AOS-LB foam lamellae.Instead,oil was redirected into the plateau borders where the accumulated oil drops delayed the rate of film thinning,bubble coalescence and coarsening.

Green Lignosulphonate as co-surfactant for wettability alteration

Surfactant flooding is one of the common tertiary method to recover remaining oil in the reservoir, byreducing the interfacial tension (IFT) between two immiscible fluids nevertheless, current surfactantforms emulsion and difficult to achieve ultra-low IFT between the water and oil without addition of cosurfactant. In this research, two types of anionic lignosulphonate-based surfactants, Sodium Lignosulphonate (SLS) and Calcium Lignosulphonate (CLS) are chosen as co-surfactant. The main surfactantused in this project is the common anionic surfactant, Sodium Dodecyl Sulfate (SDS) at a fixed concentration of 4 mmol/l. Each type of co-surfactant with different concentrations (0.5%, 1.0%, 1.5% and2.0 wt %) was mixed with 4 mmol/L of SDS at each test tube to create the surfactant solution. The result ofthe experiment showed that at 0.5 wt % for SLS and CLS surfactant solution, the contact angle of oil tosurface lowered down with a reduction of 6° and 7° respectively. This indicate that the system will bemore water-wet which the oil droplet will be less adhesive to the rock surface. In conclusion, by using theoptimum concentration of 0.5 wt % lignosulphonate as co-surfactant is able to alter the wettability ofrocks and it is recommended to test the biological-based co-surfactant at increasing temperature as analternative to enhance the surfactant flooding performance which improves the oil recovery.