Correlations and analysis of cuttings transport with aerated fluids in deviated wells

A study of cuttings transport at intermediate inclinations using aerated fluid, to determine the amount of solids that exist in the wellbore and minimum flow requirements for clean-hole condition, is presented. The experimental program included more than 300 tests, performed with a large-scale facility [100-ft-long flow loop with 8-in. outer diameter (OD) casing and 4.5-in.-OD drill- pipe]. The angles of test section inclination were 30 degrees, 45 degrees, and 60 degrees. from vertical. Four pipe-rotational speeds (0, 40, 80, and 110 rpm) were used for different liquid-and gas-flow-rate combinations. New correlations were found to estimate the required critical-gas-flow rates for hole cleaning at specified liquid-flow rate and drillpipe-rotation combinations, and to predict volumetric cuttings concentration as a function of air and water flow rate, drillpipe-rotational speed, and inclination angle.