Study on rheology of water-based drilling fluids under low temperature

Deepwater drilling would be an inevitable tendency in China recently and in future. The low temperature in deepwater formations can seriously influence the rheology of deepwater drilling fluids, and makes a big challenge to rheology control of drilling fluids. The oversea present research situation of drilling fluids’ rheology affected by temperature was analyzed. The impact of temperature and pressure on viscosity and shearing force of different water-based drilling fluids was researched, using a new self-developed deepwater drilling fluids fundamentality performances simulating equipment and FANNIX77 rheometre, which provided a laboratory research base for deepwater drilling in China. The results indicated that temperature has a similar influence on viscosities of different drilling fluids, which increases with temperature declining. It increases slowly when the temperature declining from high to room temperature, but changes swiftly when the temperature is lower than room temperature. There is a different influence on shearing forces by temperature for solid-content and non-solid drilling fluids. The shearing force of the non-solid drilling fluid decreases with the temperature declining, but the solid-content drilling fluid increases. Pressure has almost no influence on viscosities and shearing forces of water-based drilling fluids.