The Experimental Study On Water-based Drilling Fluid Lubricant To Resistant High Temperature And Salts

Salt paste layers,high pressure brine layers and high temperature formations are frequently encountered in complex deep well drilling.Under such conditions,water-based drilling fluid lubricants must have excellent temperature resistance,salt and calcium resistance,and high-density drilling.It also provides effective lubrication in the liquid.However,currently used lubricants for water-based drilling fluids cannot meet the above stringent requirements.Therefore,there is an urgent need to develop a multifunctional lubricant for high-density water-based drilling fluids and resistant to high temperatures,saturated sodium salt,and calcium.In this paper,based on the special requirements of complex deep well high temperature,high density and high salinity water-based drilling fluid lubricant,a series of lubricants with temperature resistance of 180 ?-200 ?,anti-saturation salt and anti-calcium 6000 mg/L were developed with orthogonal experiments.The product has good long-term stability and a fluorescence level of less than 3 levels.The lubrication of the newly developed lubricant in fresh water base slurry,saturated brine base slurry,calcium-containing brine-based slurry and high-temperature high-density drilling fluid was evaluated.Experiments show that the reduction rate of the lubricating coefficient of the experimental slurry before aging is higher than 70%,and higher than 80% after aging,and has little effect on the viscosity and fluid loss of the drilling fluid.Its compatibility in high temperature and high density drilling fluid is good.The comprehensive performance is better than similar products at home and abroad.The adsorption characteristics,the adsorption characteristics of the newly developed lubricant on the surface of bentonite and the metal surface,and the effects of high temperature and high salinity on the lubrication effect were investigated by adsorption experiments,contact angle experiments.With the four-ball friction and wear test,the strength of the newly developed lubricant on the metal surface was investigated,and the microscopic mechanism of its interaction with the metal surface was explored in combination with the XPS test.Experiments show that the newly developed lubricant can form "L" type adsorption on the metal surface;the higher the experimental temperature,the larger the adsorption amount;the degree of mineralization has little effect on the adsorption amount.Therefore,the newly developed lubricant has strong resistance to temperature and high salinity,can form an extreme pressure adsorption film on the metal surface,and is not easy to desorb,can cause the wettability reversal of the metal surface,and significantly reduce the surface friction.Thereby it exerted the effect of high efficiency of reducing friction and reducing drag.