Flexible wellbore model coupled to thermal reservoir simulator

Abstract

A flexible wellbore (FW) model was coupled with a thermal reservoir simulator in order to model the complex behaviour of oil wells. The FW model simulated up to 3 tubing strings in an annular space running in any direction and combined with various types of casings and string lengths. The tubing strings communicated with each other through the annulus. Radial conductive heat transfer between the tubing and the annulus occurred along the full tubing length. Flow regime was a function of liquid and gas velocities for each flowing stream. The flow regime was used to calculate frictional pressure drop, and axial and radial heat transfer. Three case studies of steam assisted gravity drainage (SAGD) processes were used to demonstrate the model and compare its performance with conventional analytical methods. The study showed that more complex wellbore behaviour and interactions increased computational times. It was concluded that the FW model can effectively solve multi-stream well equations when coupled to a thermal reservoir simulator. 6 refs., 13 figs.