Effect Of Nano Particles Addition On Drilling Fluid Properties And Anti Friction Performance To Aluminum Alloy Drill Pipe

When the drilling pipe putting up and down in the well during the drilling process, it will inevitably contact with the inner wall of casing,which will cause the frictional wear,especially in drilling deep well, ultra-deep well, horizontal well, cluster well and highly-deviated well. Although aluminium alloy pipe has small density, high specific strength, good corrosion resistance, but the abrasive resistance is not well enough. Small elasticity modulus and large lateral displacement let aluminium alloy pipe frictionally impact with the wall of well more frequently than steel pipe, and then cause the pipe whirling near the wall of well at a high speed. When under the complex conditions, aluminium alloy pipe is more likely to occur to friction wear and failure than steel pipe.For solving this problem, on the one hand can try to improve the frictional resistance of aluminium alloy pipe, which way is very difficult, on the other hand can try to increase the friction coefficient between aluminium alloy pipe and casing pipe by thinking about how the lubricating property of drilling fluid affect the drilling work.Because the lubricating property of drilling fluid is the first and foremost regulatory factors for affecting the drilling torque, revoling resistance and lifting resistance of drill stem and the abrasion of drill tool, the good lubricating property can make the drilling fluid reduce the abrasion of drill bits and tools and prevent the drill bits from adhesion sticking, which can make the drilling accident be handled easily.Domestic and overseas reseachers have used the nanoparticle for improving the properties of drilling fluid, because its minisize andsurface effect. Its little dosage conforms to the development trend of drilling fluid low solid phase turning into free soild phase. At the same time, the excellent lubricating and rheological property of nanoparticals can improve the property of drilling fluid significantly.Usually, the lubricating property of water-based drilling fluid is bad than oil-based drilling fluid. In this paper, nanoparticles had been added into water-based drilling fluid to improve its lubricating property. Three kinds of oxide nanoparticles which were nano Al2O3, TiO2 and SiO2, nano-graphene, GO and nanodiamond were chosed as property-modifying additive of drilling fluid. The extreme pressure lubrication device and pin disk friction wear apparatus had been utilized to study how the different kinds and concentrations of nanoparticles affecting the lubricating property and frictional reduction effect of water-based drilling fluid.The results show that the drilling fluid containing SiO2 particles has the best properties of lubrication, filtration and antifriction. When the adding amount of SiO2 nanoparticles was 0.4%, the filtration was minimum, the reduction rates of lubricating and friction coefficients were 15.6% and 32.0% respectively with smooth wear scar, Wear volume decreased by 26.1%,the friction reducing effects was the most evident. The second is graphene /GO to improve the performance of the drilling fluid is obvious. When the adding amount of GO nanoparticles was 0.075%, the filtration was minimum, the reduction rates of lubricating and friction coefficients were 12.6% and 19.8% respectively with smooth wear scar, Wear volume decreased by 21.7%.The water-based drilling fluid containing nanoTiO2 and nanoAl2O3 and nanodiamond have limited lubricating properties effects. When the concentration of the nanoparticles was higher than 0.5%, adding amount of GO more than 0.075%, nanodiamond over 0.2%,the friction reducing effect decreased with obvious delaminationg and wear.Based on above testing results, 0.4% nanoSiO2, 0.075% GO, 0.2% nano-diamond powders had been added into the SK-II drilling well, which is belong to the project of the cretaceous period Songliao basin continental deep scientific drilling. The results show that both GO and nano diamond powders had the effect for field drilling fluid lubricating and friction reducing. Drilling fluid containing 0.4% nanoSiO2 had the best combination properties, which make the lubrication coefficient of field drilling fluid decrease 20.3%, the reduction rate of friction coefficient increase 29.7% and the abrasion lose of aluminium disk decrease 24.3%.