Numerical prediction of flow behavior of cuttings carried by Herschel-Bulkley fluids in horizontal well using kinetic theory of granular flow

Abstract

The cuttings transport was numerically simulated based on kinetic theory of granular flow in combination with sliding mesh for drill pipe rotation in the horizontal well. The Herschel-Bulkley (H-B) model was implemented to describe the rheological behavior of drilling mud. Three distinguishable flow regions of cuttings and swaying phenomenon of cuttings distribution along the direction of drill pipe rotation were observed. The granular temperature of cuttings is high near the wall of drill pipes, which indicates that the energy from the rotating drill pipe is transferred to cuttings. Effects of three rheological parameters (τ0, KHB and n) on the flow behavior of cuttings and HB fluid were analyzed. With the increase of Herschel-Bulkley fluid rheological parameters, the height of cuttings bed decreases, and the axial flow of cuttings at the lower side is significantly enhanced, but the pressure drop through the annulus is increased. When the value of consistency coefficient and flow behavior index of H-B fluid is low, the cuttings transportation in the wellbore is unstable with the pulsation of cuttings volume fraction in the annulus. Among the three rheological parameters, the flow behavior index plays the most significant role in pressure drop through the annulus.