Physical Properties of Drilling Fluids at High Temperatures and Pressures

Summary Rheological and dynamic filtration properties are presented for water- and oil-based drilling fluids. The physical properties were obtained by use of the DYNAMIC HPHT® test system at test temperatures to 400°F [478 K], system pressures to 15,000 psi [103 MPa], and differential pressures to 600 psi [4.1 MPa]. The data indicated that the de Guzman-Andrade law can be used to describe the temperature effects on the viscosity of oil muds. We also observed that dynamic filtration rates of drilling fluids are greatly affected by solids plugging the pore space in the formation. Temperature and pressure affect dynamic, filtration by changing the dispersion of the solids in the fluid.