The present paper is a review of various borehole cleaning parameters and rheological properties of drilling mud which affects the cuttings transport. This parameter influences the borehole cleaning in horizontal and directional drilling. Inefficient borehole cleaning is the major challenge encountered in oil and gas well drilling. As the need for directional and horizontal wells increased, the borehole cleaning problems have also shifted from vertical to horizontal geometries in the past few decades. Poor borehole cleaning can result in expensive drilling problems such as stuck pipe, slow drilling rate, lost circulation, premature bit wear, high torque and drag, pack-off, formation breakdown, cuttings and power loss. If the borehole cleaning is not performed properly, it can lead to the loss of the well. The borehole cleaning problems not only lead to economic losses but also increase the nonproductive time. Thus, it is very essential to understand the borehole cleaning problems and various parameters affecting it. In this study, the different rheological and drilling parameters which affect the borehole cleaning parameters have been reviewed. The study also involves various parameters which can be very helpful in evaluating the borehole cleaning. The major factors found which affects the borehole cleaning are drilling fluid rheology, velocity of drilling fluid, borehole inclination, eccentricity and rotation of the drillpipe.
