Numerical Simulation of Foam Flow in Annulus With Wellbore Heat Transfer

Abstract

In the study of hydraulic parameters in foam drilling, most foam hydraulic models were built based on the assumption that wellbore temperature was equal to formation temperature. But energy exchange takes place among annular foam fluid, formation and drill string, there may be a discrepancy between wellbore temperature and formation temperature. The effects of heat transfer on foam flow in annulus were investigated by numerical simulation in this paper. Simulation results show that due to the influence of temperature on pressure, the changes of annular pressure are transient. And foam fluid density, viscosity and other physical parameters are change with pressure. During foam fluid transports the solid particles from bottom to surface, solid particles accelerate and foam decelerates. When high solid particles concentration zone is reached, foam velocity decreases to a minimum value, and then increases due to the decrease of solid particle concentration. When cuttings velocity increases to a certain value, cuttings transport with a constant velocity. Key words : Heat transfer; Foam drilling; Annulus pressure; Foam velocity; Numerical simulation