Two-phase flow simulations at 0−4o inclination in an eccentric annulus

•The effect of the eccentricity of the annulus on the flow regime, pressure gradient and wave and slug frequencies were studied.•Slug frequencies are decreased for all simulated cases compared to the experiments.•Pressure gradients decrease as the eccentricity of the annulus is increased.•A pressure gradient increase was observed with increasing liquid holdup while mixture velocity is kept constant.