Variation of Flow Regimes in +2 Degree Inclined Wet Gas Environments and Drag Reduction

Experiments were carried out to examine the study of flow patterns and the performance of drag reducing agents in a 40 m long, 10.16 cm diameter, + 2 degree inclined wet gas pipeline environments. Superficial liquid velocities ranging from 0.03 to 0.1 m/s and gas velocities from 2 to 10 m/s were investigated with the commercial DRA concentration of 0, 25 and 50 ppm. Light viscosity oil was used as the liquid phase and carbon dioxide was used as the gas phase. Variation of flow patterns in horizontal and +2 degree pipes are reported in this paper. The effect of inclinations on the pressure gradient is also presented. The stratified flow was dominant flow pattern in horizontal wet gas pipelines. However, for certain conditions, slug flow along with big wave forms was observed in 2 degree upward flow. The pressure gradient for 2 degree upward flow was higher than horizontal flow since the height of the liquid film was higher in case of upward flow. The pressure gradient decreased significantly as drag reducing agent was added in the pipeline. For slug flow in + 2 degree inclination, the pressure gradient reduction of 19 % was achieved for superficial liquid and gas velocities of 0.03 and 2 m/s at a flow improver concentration of 50 ppm. This was because the flow characteristics such as slug frequency and wave activity were changed with the addition of DRA.