Study On Water - Based Drilling Fluid System With Temperature Of 200 ℃ And 1.50 ~ 2.30g / Cm ~ 3

High temperature resisting high density water-based drilling fluid is an important technical guarantee to the success of deep wells, kirgiz, dina etc bebop blocks In China’s western tarim oilfield are preparing to drill deep wells over 7000m,whose predicting temperature reach 180～200℃, formation pressure coefficients reach 1.50～2.25. But domestic currently deep wells drilling fluids of water-based is within 18℃mostly, and density do not exceed 2.0g/cm3, can not satisfy the need of deep well drilling. Therefore, it is an urgent need to develop anti-200℃high density water-based drilling fluids.Though analyzing the difficultities of deep drilling fluid,this paper described the mode of actions of High Temperature and its effects on the drilling fluids’performance; analyzed the various barite factors’ effect on system performance, includes volume content and surface properties and particle size, pointed out that in practical applications we should streamLined additives,strictly control the content of bentonite within claycapacity limits and use barite with small particle and level.Optimized usual additives though single factor method;For barite with small size and level, through by the determination of adsorption, confirmed that preferred barite adsorped SMC and SMP-Ⅲand FV-2; by scanning electron microscopy, confirmed that preferred barite can not only adsorp additives but also participate in the formation of system structure, which ensuring its suspension stability and rheological property.Combined with Calcium humic acid’s very good capacity of depressing filter loss and dilution under hightemperature, introduced CaO,Calcium humic acid has been produced by CaO reacted with SMC solution.Research on properties changes cased by the amount of additives,confirmed SMC and SMP-IIIand FV-2 work well, DJ-land calcium carbonate can further reduce the filtration of system,developed the anti-200℃united dispersed phase system 3%Bentonite+0.5%FV-2+0.3%CaO+7%SMC+5%SMP-III+3%DJ-1+3%Calcium carbonate (1250 Head:2250 Head-2:1).Adjust the treatment and the added amount of the additives, at the same time use barite aggravating, developed the anticipate anti-200℃density 1.50-2.30g/cm3 water-based drilling fluids and estimated system performance,which showed that the system own good rheology property and filtration properties, strong inhibition, outstanding the tolerance to fouling, good sealing characteristic, good thermostability, which provided basis for tarim oilfield drilling technology research, choosing deep well drilling fluids resistant to temperature high density.