Bottoms-Up

Annular velocity & slip — the figure above is how fast fluid travels up the annulus (rate ÷ capacity). Cuttings don't ride it for free: each chip settles back at its own slip velocity, so what lifts debris is the net — annular velocity minus slip. Bigger, denser cuttings slip faster; turbulent flow lifts better than laminar; and a wide upper casing is where returns slow and solids linger. This tool shows the fluid velocity, not the slip — actual slip depends on cutting size, density, and fluid properties.