Characterization of oil water flows in inclined pipes

The flow of oil-water for different inclination angles (0°, ± 1°, ±2° and -5°) was studied through the analysis of high-quality experimental data on flow pattern, pressure gradients, water holdup and phase distribution (Atmaca (2007). A total of 324 tests were conducted in a 0.0508-m. ID 21.1 m. long, inclinable test section using tap water and mineral oil (with a density of 0.85 gr/cm ³ and viscosity of 15 cp) with superficial velocities ranging from 0.025 m/s to 1.75 m/s. Oil-water flow in the petroleum industry is a common occurrence during production and transportation of gas-oil-water in pipes. Facilities design is strongly dependent on the flow behavior. The specific applications include design and troubleshooting of flow lines and wells, separator design, interpretation of production logs, etc. Non-intrusive high-speed camera technique was used to determine the flow patterns at various conditions. Experimental flow pattern maps were compared against Trallero (1995) and Zhang and Sarica (2006) models. Trallero model predicted the most flow pattern boundaries well except stratified flow pattern. For most of the cases, the pressure gradients were over predicted by the Zhang and Sarica model. Quick closing valves are used for holdup measurements giving phase slippage information. For the low superficial velocities, slippage behavior was observed very clearly for upward and downward flow. For the high superficial velocities, slippage effects were diminished. Representative phase distributions, and interface boundaries were observed for different flow conditions by examining conductivity probe data. This paper provides significant insight in phase distribution and slippage behavior. The results presented in this study are applicable not only to oil-water flow but also to three-phase gas-oil-water flow models.