Masoud Noei - M.Sc. Student, Shahrood University of Thechnology
Mehrdad Sleimani Monfared - Assistant Professor of Student, Shahrood University of Thechnology.
Mohammad Fazaelizadeh - Assistant Professor of Student, Amirkabir University of Thechnology

In spite of many recent technology improvements in drilling, hole cleaning remains a significant challenge, especially in deviated and horizontal wells. Inadequate hole cleaning can result in several problems, such as bit wear, slow drilling rate, increased ECD (which can lead to formation fracturing), high torque, drag, and in the worst case, the drill pipe can be stuck.The critical mud flow rate for cleaning the well while drilling can be defined as the minimum annular fluid velocity, required to maintain a continuous upward movement of the cuttings, and no bed forming on the lower side of the wellboreThe paper employs two models developed by an empirical approach, namely Larsen‟smodel and Rubiandini‟s model and compare them with experimental. We observe, Larsen’s model is more reliable rather than Rubiandini;s model.

Drilling Fluid, Hole Cleaning, Cuttings Transport, Minimum Flow Rate