Experiments and model development for high-viscosity oil/water/gas horizontal and upward vertical pipe flows

The effect of high oil viscosity on flow characteristics of oil/water/gas three-phase flow was experimentally studied in both horizontal and upward vertical pipes. 300 tests were conducted in a 5.25-cm ID pipe at 2.59 MPa pressure. Three oil viscosities, namely 0.57, 0.28 and 0.15 Pa·s, were used. Both superficial oil and water velocities varied from 0.1 to 1 m/s and superficial gas velocity changed from 1 to 5 m/s. Flow patterns were observed through a high pressure sapphire window and recorded with a high speed video camera system. Pressure gradient and liquid holdup were measured and used to compare with Zhang and Sarica (2006) unified model and OLGA steady state mechanistic model predictions to identify the deficiencies in both models.;A mechanistic model to predict the slug liquid holdup for low and high oil viscosities was developed. The model is based on two shears, one between the slug front and pipe wall, and the other between slug body and liquid film. The proposed model was validated against experimental data with wide ranges of oil viscosity, pipe ID and inclination angle. A closure relationship for average slug length was developed based on an inverse dimensionless viscosity number and can be used for wide range of oil viscosities. Zhang and Sarica (2006) unified model performance is improved after incorporating current slug liquid holdup and average slug length models.