A new comprehensive mechanistic model was developed to predict flow pattern and flow characteristics such as pressure drop and liquid holdup in vertical and deviated wells. The model includes five flow patterns: bubbly, dispersed bubble, slug, churn and annular flows.
Flow pattern prediction incorporates the transition models proposed by Barnea1 (or Taitel et al.2 ) for dispersed bubble flow, Ansari et al.3 for annular flow, Tengesdal et al.4 for churn flow, and a new bubbly flow transition model. For each predicted flow pattern, a separate hydrodynamic mechanistic model is proposed. A new hydrodynamic model for bubbly flow has been developed, and the Chokshi5 slug flow model has been modified significantly. The Tengesdal et al. and Ansari et al. models have been adopted for churn and annular flows, respectively.
The comprehensive model is evaluated using a well databank of 2,052 cases covering a broad range of field data. Pressure drop predictions with the model are also compared with those using the Ansari et al., Chokshi, Hasan and Kabir6 , and Tengesdal mechanistic models, and the Aziz et al.8 , and Hagedorn and Brown9 correlations. The results of the comparison study show that the proposed comprehensive mechanistic model performs the best and agrees with the data.