Investigations of a drilling operation by using a simplified gas-liquid mathematical model

Abstract

There was a strong wish to investigate the physics of fluid flow involved in drilling operations where nitrogen injection is used to lower the hydrostatic pressure. This work is based on a reduced version of the full drift-flux model first presented to the academic community by Zuber and Findlay that Dr. Steinar Evje developed and programmed numerically in MATLAB. The mathematical model implemented to predict the behavior of the system is a simplification of the full “transient gas-liquid drift flux model” , where a system of two strongly coupled “advection-diffusion” equations is obtained . The model allows exploring relevant phenomena for drilling operations including the effect of liquid and gas expansion on pressure distribution along the wellbore.