ANNUAL TRANSACTIONS OF THE NORDIC RHEOLOGY SOCIETY, VOL. 13, 2005

Powder size particles mixed into polymer fluids with two or three-parametric power law rheology may precipitate in the quiescent fluid very slowly, due to the very high viscosity in the fluid at low shear rates. They will normally settle much faster if the fluid is subjected to horizontal shear flow. This article describes a method to measure particle settling velocities in horizontal, laminar shear flow at a constant shear rate. The method may particularly find application in classifying drilling fluids used in the oil industry, where loosing weight material from the fluid during drilling of inclined or horizontal oil or gas wells sometimes can create severe operational problems