Modeling of cuttings transport in directional wells using two-layer model

A previously developed transient cuttings transport model using a two-layer model was modified to enable more practical simulation over the whole trajectory of a directional well. Two-layer model is usually used to describe solid-liquid two-phase flow in pipes in which cuttings bed is formed and the boundary between layers can be clearly recognized. In this study, two-layer model was extended to apply to describing cuttings transport behavior in relatively low hole inclination angles ranging from vertical to about 55 degrees, in which continuous cuttings bed was unlikely formed. Of the constitutive equations used, cuttings re-entrainment rate was re-formulated as a function of hole inclination angle and was corrected to match experimental results. To evaluate the modified model, field scale simulation on cuttings transport was carried out for a simple horizontal well. Simulation results showed that the modified model could successfully demonstrate transient behavior of cuttings transport over the whole trajectory of the well.