Our module for hole cleaning calculations employs both static and dynamic methods.
The static method is based on the studies by Larsen, described in SPE 25872. It enables modeling of the critical annular velocity of drilling fluid and the equilibrium cuttings bed under steady-state drilling conditions.
Mud critical transport velocity vs inclination, lab data SPE 25872
The static method has been validated through numerous laboratory experiments described in SPE 25872 and SPE 20925, using various drilling fluid types and parameters, and has demonstrated high accuracy.
Cutting bed vs inclination, lab data SPE 25872
The dynamic method was developed by extending the static method into the time domain. It allows for modeling changes in the cuttings bed over time, enabling the prediction of circulation time at the bottom hole to ensure acceptable wellbore cleaning.
The dynamic method has been validated against limited laboratory data from SPE 56406. It showed satisfactory accuracy for high wellbore angles (>60 degrees). For angles in the range of 30–60 degrees, the method provides a more conservative cleaning estimate compared to reality: in practice, less time is required to remove the cuttings bed.
Cutting weight in annulus vs time, lab data SPE 56406