Numerical study of drilling fluids flow in drilling operation with pipe rotation

As one of the major functions of drilling mud is to maintain pressure inside a wellbore to avoid any invasion of unwanted high-pressure, this makes the determination of this pressure loss a very complicated task in the petroleum drilling industry. The aim of this paper is to predict the behaviour of drilling fluid flowing inside rotating pipe then in a concentric annulus at various values of inlet velocity and rotation speed. The governing equations (continuity and momentum) are solved numerically using CFD simulation with FLUENT commercial code. The flow is laminar in three-dimensional steady-state with non-Newtonian fluid. The results are visualized as: contours, pressure drop and velocity. The results show that pressure drop is decreased when pipe rotational speed increase. At the conditions of rotation speed of 300 rpm and inlet velocity of 1.2 m/s, the pressure loss present a significant decrease compared to the other conditions, furthermore, an uniform distribution of velocity in the pipe and annulus, is indicated. Therefore we can considerate this conditions of rotation speed and inlet velocity as optimal conditions.