Erasmus Mensah, Bob L. Herd Department of Petroleum Engineering
During intermittent gas lift, a low-density fluid (gas) is used to lift a high-density fluid (oil) from the bottom of the well to the surface. As a result of the oil having a higher density than the gas, some amount of the oil falls back in the form of droplets or in a film along the wall of the tubing to join the next slug of oil. However, there is still no method to accurately estimate the fallback factor in the presence of several variables in the process.
In this paper, an attempt was made to develop an analytical model to predict the fallback factor of an intermittent gas lift cycle by continuing the mechanistic model from literature to include the change in length of liquid slug to estimate the fallback factor.