Study On Nanoparticle Stabilized Micro-foam Drilling Fluid System

In previous studies,the influence of the type,concentration,particle size distribution of nanoparticles,foam stabilizer and surfactant on foam stability was mainly analyzed,but the wettability of nanoparticles and the influence of the synergistic action of nanoparticles with surfactant and foam stabilizer on foam stability were ignored.Reservoir protection performance of micro-foam drilling fluid after the introduction of nanoparticles was rarely studied.Based on the above related issues,this paper studies the fluid discharge rate,rheology,filtration property and bubble growth rate of micro-foam drilling fluid under the cooperative influence of different concentrations of surfactant and bubble stabilizer from the mechanism of the influence of nanoparticles,surfactants and bubble stabilizer on the stability of microfoam.The synergistic effects of nanoparticles with surfactant and foam stabilizer were analyzed,the plugging performance and reservoir protection ability of the micro-foam drilling fluid system were analyzed.The results show that the critical micellar concentration measured by conductivity method is about 2300mg/L.The experiment explores the influence of the change of xanthan gum concentration and surfactant concentration on the bubble size,liquid discharge rate and other factors in the micro-foam drilling fluid system under specific conditions.Three common nanomaterials were selected and it was verified that the synergistic effect of 2% partial hydrophobic Si O2 nanoparticles and 0.33% SDS surfactant was the best.After the stability,filtration loss and rheology analysis,it was verified that the microfoam system had significantly improved the foam stability effect after the introduction of specific concentration of nanoparticles.The synergistic action of nanoparticles and surfactants increased the LSRV of the micro-foam drilling fluid and significantly improved the cutting-carrying capacity of the micro-foam drilling fluid.The presence of nanoparticles effectively reduces the filtration loss.The higher the injection rate of microfoam drilling fluid,the better the plugging effect.In different saturated fluid reservoirs with injection rates of 5m L/min,the pressure difference required in the initial stage of micro-foam drilling fluid injection is larger,indicating better plugging effect.The micro-foam drilling fluid has lower damage degree to the reservoir saturated with mineral oil.When the saturated fluid is simulated formation water,the plugging performance of microfoam drilling fluid is better than that of hydrophilic rock sample.