Rheological properties of the synthetic drilling fluid in deep-water drilling conditions

The synthetic drilling fluid system is currently widely applied in deep-water drilling operation.Meanwhile,the low temperature rheological property of the synthetic drilling fluid was one of the problems widely concerned in deep-water drilling.The present paper investigated effects of various factors,such as emulsifier types,organic clay addition,oil-to-water ratio and mud density,on the low temperature rheological property of the liner α-olefin synthetic drilling fluid by measuring its viscosity-temperature properties at different compositions.Then,the paper discussed the influence of base-oil types and viscosity on viscosity-temperature properties of the water-in-oil drilling fluid.The experimental results demonstrated that the low temperature rheological property of the liner α-olefin synthetic drilling fluid was significantly influenced by the emulsifier type,followed in turn by organic-clay addition and oil-to-water ratio,while weighting materials affected the low temperature rheological property of the synthetic drilling fluid much less.The low temperature viscosity of base oil was most decisive to the viscosity of the deep-water synthetic drilling fluid system.The liner α-olefin synthetic drilling fluid was superior to the mineral-oil-base and gas to liquid-base drilling fluids in low temperature flowability,being applicable to deep-water drilling operation.