Investigation of drill pipe rotation effect on cutting transport with aerated mud using CFD approach

Abstract

In drilling with aerated mud, appropriate hole cleaning has a great impact on decreasing the drilling time and cost. Thus, investigating the impact of diverse drilling parameters such as pipe rotation on the hole cleaning looks as a key. In this study, the combination of k-ε turbulent model and Eulerian-Eulerian multiphase model was used to investigate the three phase flow in the concentric annulus. Furthermore, the collision of cutting – cutting, cutting-drill pipe and cutting-well was considered in the simulations. In the first step, for validating the computational setup, the simulation outcomes were compared with the previous experimental works. The impact of pipe rotation on hole cleaning at various water and air flow rates, inclination and cutting sizes was scrutinized. The simulation results demonstrated that the impact of pipe rotation on the hole cleaning can be different depending on the different hole conditions. In the low inclination and air rates, rising the pipe rotation from 0 to 75RPM brings about dropping the cutting concentration, but increasing the pipe rotation from 75 to 125RPM comes about raising the cutting concentration. On the other hand, in low inclination and high flow rates of air, rising the pipe rotation causes a high accumulation of cutting. Lastly, at high inclination, the cutting concentration in annulus decreases with increasing the pipe rotation and this is independent of air and water flow rates. The simulation outcomes also showed that the impact of pipe rotation on hole cleaning at large cutting size is not as much as small cutting size.