A mechanistic model for vertical and inclined two-phase slug flow

This work proposes a mechanistic model for predicting the flow behavior for upward vertical and inclined two-phase slug flow. Expressions for bubble rise velocity, liquid film velocity, liquid holdup around the Taylor bubble, and liquid slug void fraction are derived from the relationships between the two-phase velocities. Based on measured void fraction data, the proposed liquid slug void fraction equation exhibits better performance than the existing models. The proposed mechanistic model and twelve commonly used slug models are compared with the Tulsa University Fluid Flow Projects data bank (1052 well cases). This data covers a wide range of the flow conditions, well geometry and fluid properties. The comparison indicates that: (1) the new model is straightforward and is therefore easier to apply than other models, (2) the model is in very good agreement with the measured data and (3) the model performs best and clearly outperforms all other models.