Prediction of pressure drop and liquid holdup in vertical two-phase flow through large-diameter tubing

This research aims at developing a comprehensive model to predict pressure drop in vertical, upward two-phase flow in wellbores. Another important objective is to gather quality data in a test facility that operates in near-field conditions.; Data are gathered from 324 tests for widely varying flow rates for an air-water fluids system in a 3{dollar}{lcub}1over2{rcub}{dollar} in. diameter, 1348 ft long, vertical test section. Each data set consists of flow rate measurements, pressure and temperature measurements at eight locations along the test section, and non-intrusive holdup measurement at 490 ft below the surface using a custom gamma-ray densitometer.; A new comprehensive model to predict pressure gradient considers three flow patterns: bubble, slug and annular. The bubble to slug transition is developed using a drift flux approach that also provides holdup and pressure gradient for bubble flow. The transition from annular to slug flow is governed by a two fluid approach based on a coaxial-cylinders model that also yields holdup and pressure gradient for annular flow. The pressure drop prediction for slug flow is based on a cellular model. Some of the constitutive equations required to close the model are developed from the data gathered by an earlier investigator. Computer code for the model that can be used like existing correlation subroutines requires no unusual input data.; In comparison with eight other methods the model performs best for the measured data. The pressure drop predictions of the new model are also compared to these eight methods using an independent data bank of 1712 data-sets. The model also better predicts than the other methods for the independent data bank, yielding the smallest average error and the least scatter.