Mini-hydrocyclones applied to the removal of solids from non-Newtonian fluids and analysis of the scale-up effect

Abstract

In the solids control system, the removal of fine solids from drilling fluid is performed by decanter centrifuges. The use of these centrifuges is limited not only by the costs involved but also by the available space on the oil rig, so they cannot process the entire volume of fluid circulating in the drilling system. This paper proposes the use of hydrocyclones to support decanter centrifuges, aiming to increase the removal rate of fine material from the fluid to be reinjected into the well. To this end, a highly efficient with low flow ratio hydrocyclone geometry was tested, using non-Newtonian fluids with a particulate matter size distribution similar to the conditions encountered in the field. Empirical expressions were obtained to predict the total separation efficiency, flow ratio, capacity and cut diameter of the equipment as a function of the operating conditions. The hydrocyclone scale-up results indicated that the larger device maintains practically the same separation performance as the original device, but provides an evident improvement in processing capacity.