Modeling Pressure-Viscosity Behavior of Oil-Based Drilling Fluids

Organoclay suspensions are commonly used as drilling fluids in environments where they are submitted to high pressure and temperature for long periods of time. Consequently, both volumetric and thermorheological properties are among their most important quality parameters concerning this application. The overall objective of this work was to study the pressure and temperature dependence of both viscosity and density for oil-based drilling fluids. With this aim, Pressure-Density-Temperature (P rho T) data and pressure-viscosity-temperature data were modeled by using different equations. All these equations predict the evolution of the viscosity of drilling fluids with pressure and temperature, for engineering purposes, fairly well.