Developments in the shear vane test to measure the gel strength of oilwell cement slurry

Synopsis The shear vane test, and the rheological measurements made with it on a cement slurry typical of those used in the oil drilling industry, are described together with comparative results on three conventional viscometers (Fann Viscometer, Contraves Rheomat 15, Weissenberg Rheogoniometer). It is considered that the shear vane can have many advantages for particulate suspensions and, because slip layers are avoided, the vane measures a more fundamental property than that determined using a smooth bob. A variety of instrument parameters which can affect the gel strength measured by vanes have been examined and the most important effect was found to be the measuring system stiffness. The use of different instruments could alter the rate of application of shear stress, until first flow occurred, by at least two orders of magnitude.