Numerical simulation of gas-liquid two-phase flow in wellbore based on drift flux model

A general model and computational code for transient gas-liquid two-phase flow in wellbore are developed in this paper. The model consists of mass conservation equation for each phase and mixture momentum conservation equation. The interactions of each phase are taken into account by invoking the Shi slip relation in the proposed model. The model is numerically solved by the second order AUSMV scheme, which is obtained by using classical MUSCL technique. The computational code is validated by the classical numerical cases, Zuber-Findlay tube and complex mass transport problem. The simulation results show good agreement with the references which are obtained by using first-order flux-limited Roe scheme with refined grids. The computational code also succeeds in obtaining the transient behavior of each phase for a normal gas-kick occurrence in wellbore. The simulation results illustrate the degree of pressure variation in the upper wellbore is greater than that in the lower wellbore. The pressures of wellbore increase before the corresponding gas mass flow rate reach max inlet gas mass flow rate, then decrease.