Slot Flow Approximation for Herschel-Bulkley Drilling Fluid through Eccentric Annuli

TLDR: In this paper, the authors developed and analyzed the numerical solution of fluid flow through eccentric annuli which is represented by slot of variable height with the use of Herschel-Bulkley drilling fluid.

Abstract: The studies of fluid flow through eccentric annulus has been started since early 1940’s and numbers of solution in order to enhance the efficiency of the cutting transport to the surface have been developed. The solution developed so far by many investigators is either analytical or numerical and mostly involving parameters such as velocity distribution, shear stress, shear rates and pressure drop. The aim of this study is to develop and analyze the numerical solution of fluid flow through eccentric annuli which is represented by slot of variable height with the use of Herschel-Bulkley drilling fluid. Developed numerical solution is then used to estimate the Velocity distribution in the eccentric annuli as well as to determine flow rate for a given drilling condition. In addition, the rheology of non-Newtonian fluid (Bingham, Power and Herschel-Bulkley) will be discussed. By applying the correct assumption of eccentricity ratio (k=0.3) on the numerical solution developed earlier, velocity distribution were obtained. Apart from that, by representing the eccentric annuli as slot of variable height the accuracy of the solution obtained can be improved and no iterative computation needed.