Study On Dispersion Stability Of Drilling Fluid Nano-materials

With the acceleration of the exploration and development of unconventional oil and gas resources in China,more demands are placed on the performance of drilling fluids.Due to its small size and special performance,nano-materials have attracted much attention in research and application in drilling fluids.However,nano-materials are prone to agglomeration,which will increase the particle size of the particles,causing them to lose nano-characteristics,which may affect the application effect in severe cases.Therefore,its dispersion stability is a problem to be solved in practical applications.In this paper,two kinds of nano-materials with good dispersibility were screened out,and the dispersion stability of a nanoemulsion and nanodispersion was studied.Through the influence analysis of the external environment factors,the results show that the two nano-materials have good time,shear force and pressure stability,and the temperature resistance is outstanding,but the salt resistance is poor.Therefore,the effects of Na Cl,KCl and Ca Cl₂ on the dispersion stability of nano-materials are studied in detail,and the mechanism was discussed.Aiming at the problem of poor salt resistance of two kinds of nano-materials,through the screening of modifiers,the modification process,combined with the analysis of temperature and salt resistance and the analysis of foaming,the nano-materials were successfully modified.The temperature-resistant and salt-resistant modified nanoemulsion and the salt-resistant modified nanodispersion were prepared.Finally,the application performance of the modified nanoemulsion system was evaluated.The experimental results show that as the salt concentration increases,the agglomeration behavior of the two nano-materials becomes more serious.Among them,the greater the concentration of the nanodispersion,the more the dispersion stability is affected by the salt,and the smaller the concentration of the nanoemulsion,the more susceptible the dispersion stability is to the salt.The effect of calcium chloride on both nano-materials is greater than that of sodium chloride and potassium chloride.The modifiers GX-1 and GX-2 were screened to modify the nanoemulsion.The results of modification process showed that the modifier dosage,stirring rate,modification time,modification temperature and p H value all affected the modification effect,and the temperature and salt resistance of the system were significantly affected by the amount of modifier.Finally,the formulation of the GX-1 system is:m _nanoemulsion:m _modifier:modification process is 1200rpm,30min,room temperature,p H 8.Based on the actual situation of the site dynamics,the final GX-1 system can resist saturated Na Cl and KCl to 150°C,and the GX-2 system can resist 5%Ca Cl₂ to 120°C.The long-term stability of the two systems is good,which can significantly improve the fluid loss performance and lubricating performance of the base slurry,but has no obvious influence on the rheological properties of the base slurry,and has good thermal stability in the base slurry.Compared with the results of the fluid loss test and the lubricity test,the GX-1and GX-2 systems have obvious temperature and salt resistance advantages compared with the pre-modified nanoemulsion.