Slippery Liquid-Infused Porous Surface (SLIPS) consist of a nano/micro-structured porous material infused with a lubricant fluid whose purpose is to hinder material defects and imperfections. At the same time the lubricant introduces additional friction concurring in determining the velocity of sliding drops. In this work we use a high density ratio ternary lattice Boltzmann method to model SLIPS, consisting as flat surfaces coated with a lubricant layer. We apply a body force to 2D droplets on top of the lubricant and determine the relation between body force and drop velocity as function of the amount and viscosity of the lubricant. Our results are relevant to describe the case with oil entrainment under the drops and its effect to the drop dynamics. Furthermore we explore the impact of non-Newtonian rheology of the lubricant on the dynamic law.