Abstract
We present a unique set of two- and three-phase slug-flow experiments conducted in a 766-m-long, 8-in. pipe at 45-bara pressure, using Exxsol™ D60 fluid (ExxonMobil Chemical, Houston, Texas, USA) as the oil phase and nitrogen as the gas phase. The first one-half of the pipe was horizontal, while the second one-half was inclined by 0.5°. A total of 10 narrow-beam gamma densitometers were mounted on the pipe to study flow evolution, and in particular slug-length development.
The results show that the mean slug length initially increases with the distance from the inlet, but this increase slows down, and the mean slug length typically reaches a value between 20 and 50 diameters at the outlet. At low mixture velocities (3 m/s), the slug-length distributions are in general narrower. The effect of the water cut (WC) on the slug-length distribution is significant but complex, and it is difficult to establish any general trends regarding this relationship. Finally, it was observed that slug flow often requires a very long distance to develop. Specifically, in most of the slug-flow experiments, the flow regime 57 m downstream of the start of the horizontal section was not slug flow.
The results show that the mean slug length initially increases with the distance from the inlet, but this increase slows down, and the mean slug length typically reaches a value between 20 and 50 diameters at the outlet. At low mixture velocities (3 m/s), the slug-length distributions are in general narrower. The effect of the water cut (WC) on the slug-length distribution is significant but complex, and it is difficult to establish any general trends regarding this relationship. Finally, it was observed that slug flow often requires a very long distance to develop. Specifically, in most of the slug-flow experiments, the flow regime 57 m downstream of the start of the horizontal section was not slug flow.