Abstract: Thermal conductivity measurements of a wellbore fluid may be used to derive the sag of the wellbore fluid (i.e., the inhomogeneity or gradation in particle distribution in the fluid as a result of the particles settling). For example, a method may include measuring a thermal conductivity of a fluid at two or more locations along a height of a vessel containing the fluid that comprises particles dispersed in a base fluid; and calculating a sag of the fluid based on the thermal conductivity at the two or more locations. In some instances, the temperature and pressure of the wellbore fluid may be changed and/or the wellbore fluid may be sheared to investigate their effects on sag.

Abstract: A drilling fluid conditioning system can include a centrifuge, and at least one heat transfer property sensor that outputs real time measurements of a heat transfer property of a drilling fluid that flows through the centrifuge. A method can include measuring a heat transfer property of a drilling fluid, and determining, based on the measured heat transfer property, an operational parameter of a centrifuge through which the drilling fluid flows. A well system can include a drilling fluid that circulates through a wellbore, and a drilling fluid conditioning system including a centrifuge and at least one heat transfer property sensor that measures a heat transfer property of the drilling fluid.