Characterization of oil/water flows in inclined pipes

Oil/water flow is a common occurrence during production and transportation of petroleum fluids through pipes. Understanding of oil/water pipe flow behaviors is crucial to many applications including design and operation of flow lines and wells, separation, and interpretation of production logs. In this study, the oil/water pipe flow was experimentally investigated for different inclination angles (0°, ±1°, ±2° and -5°). A total of 324 tests were conducted in a 0.0508-m (2-in.) ID 21.1-m (69.6-ft) long test section using tap water and mineral oil with superficial velocities ranging from 0.025 to 1.75 m/s. The experimental results include observations of flow patterns and phase distributions, and measurements of water holdups and pressure gradients. A high-speed video system was used to observe the mixing status between oil and water and to determine the flow patterns at various flow conditions. Quick closing valves were used to measure the phase holdups and to demonstrate the slippage between oil and water with the water cut to water holdup ratio. The experimental results of flow pattern transitions, water holdups, and pressure gradients are compared against predictions of the Zhang and Sarica (2006) model. The model performance is analyzed based on the experimental observations and the modeling considerations. Recommendations are presented for future model improvement.