The correlation is based upon a flow regime map, which is first determined, as if the flow was horizontal.It is primarily a pipeline correlation and generally over-predicts pressure drops in vertical and deviated wells. The Beggs & Brill correlation was developed following a study of two-phase flow in horizontal and inclined 1 inch and 1 ½ inch smooth circular pipes.Note: In Prosper software, the deviation correction for holdup of Duns & Ros has been added to the Hagedorn & Brown correlation Beggs & Brill (Std.): Hagedorn Brown should not be used for condensates and whenever mist flow is the main flow regime.This can result in optimistic predictions for minimum stable flow rates.It under predicts VLP at low rates (well loading is poorly predicted) and should not be used for predicting minimum stable rates.It performs well in oil wells for slug flow at moderate to high production rates It works well for bubble and slug flow regimes in a wide range of applications.
It gives the lowest possible value of Vertical lift Performance (VLP).Therefore, this correlation cannot be recommended for general use and it is provided for use as a quality control (should not be used for quantitative work). Fancher and Brown is a no-slip correlation, with no flow regime map.Multiphase flow correlations: Fancher & Brown: By inspecting the predicted flow regimes and pressure results, the User can select the correlation that best models the physical situation.
When an outflow performance simulator is used, it is recommended that a Correlation Comparison always be carried out. There is no universal rule for selecting the best flow correlation for a given application. Depending on the particular correlation, flow regimes are identified and specialized holdup and friction gradient calculations are applied for each flow regime.
They are therefore more correctly termed two-phase flow correlations. Thus flow correlations in common use consider liquid/gas interactions. The oil and water are lumped together as one equivalent fluid. This article details the most widely used correlations for the prediction of the Vertical Lift Performance.
The primary purpose of a multiphase flow correlations is to predict the liquid holdup (and hence the flowing mixture density) and the frictional pressure gradient.