an investigation of thermal stability of pickering emulsions using emulsions droplet size

Success in drilling operation extremely depends on drilling fluid performance. depletion of many oil and gas reservoirs and increase of demand for energy is caused to pay more attention to unconventional reservoirs. many of usual additives that are used for improving drilling fluid characteristics, in high pressure-high temperature (hp-ht) or unconventional conditions are unstable and hardly are applicable in these conditions. up to now, many researchers have used different nanoparticles (nps) for improving drilling fluid characteristics and overcoming drilling operation problems. in this research, various concentrations of nanosilaca as solid particle and surfactants as wettability alteration of solid particles have been used. based on the amount of water separated, which is a sign of instability for emulsion, the optimum concentration of nanoparticles and surfactants and accordingly the most stable sample has been selected. this sample has been considered for thermal stability at 110, 140, 160 and 180 f. according to the average droplet size at these temperatures, it has been shown that till 160f, stability of the emulsion is acceptable but at 180f, emulsion is unstable completely as the droplet size at this condition increases significantly.