Study on Key Additive for Water Base Drilling Fluid System of Deepwater Drilling

In deepwater,to prevent gas hydrating and keep suitable rheology at low temperature are the key properties of drilling fluid systems.A water base drilling fluid system used for deepwater drilling is developed,composed of viscosifier UFLOW synthesized by inverse microemulsion,rheology regulating agent VIS-HX modified by plant gum,and gas hydrate inhibitors NaCl,polyalcohol and polyvinyl pyrrolidone (PVP).The drilling fluid system can keep good rheology at low temperature,the YP and 63 values change slightly among the operating temperature ranges,and it can prevent gas hydrating effectively at the water depth of 2,000 m and the temperature of 3°C.