Robertson-Stiff rheological model in fracture flow

Abstract

Robertson-Stiff rheological model has been recently shown to provide a more accurate description of a drilling fluid than the Herschel-Bulkley model. In this short communication, a relation between the pressure gradient and the average fluid velocity in a fracture is derived for the Robertson-Stiff model. Practical use of the model is demonstrated using an example of one-dimensional radial flow with a Robertson-Stiff fluid displacing a Newtonian fluid in a horizontal fracture.