Investigation of the chemical composition and efficiency of drag reducing agent in a multiphase oil-water-gas system
Temple Nwoburuigwe Chikwe and Leo Chigbu Osuji
Abstract
Different concentrations of drag reducing agents (DRA) were used to envisage the efficiencies of DRAs in a multiphase oil-water-gas system. DRAs with weight concentrations of 25.0, 50.0, 75.0 and 100.0 (%) obtained from α-β unsaturated hexadecene polymer, vegetable oil, sodium palmitate and polyacrylate (pour point modifier), respectively were used. The oil-water mixture combined in a tee section flows into a 1 m3 mixing tank made of carbon steel where carbon IV oxide stored in a 30-ton liquid receiver was introduced into the system at a constant pressure of 30 barg and then, fed into the bottom of the mixing tank simulating a multiphase oil-water-gas mixture. The pressure gradient along the multiphase oil-water-gas 10.00 cm PVC pipeline was determined without the DRA as a control and then, with different concentrations. The pressure gradients for the DRA weight concentrations of 25.00, 50.00, 75.00 and 100.00 (%) were 7.57, 5.71, 3.98 and 0.77 barg, respectively, the efficiency factors (EDRA) were 0.57, 0.70, 0.75 and 0.92 respectively, the liquid densities were 0.8778, 0.8892, 0.9154 and 0.9331 respectively and the liquid velocities were 1.50, 0.80, 0.60 and 0.10 m/s, respectively. Higher the weight concentration of the DRA, the lower the pressure gradient along the discharge line of the travelling fluid, the higher the drag reducing ability of the DRA which is reflected in the %DRA and EDRA. The flow distribution and slug characteristics of DRA concentrations were also determined using the Reynolds number and fanning friction factors. The DRA with the highest concentration of 100.00% had a Reynolds number and fanning friction factor of 5.2831 and 0.0580, respectively, while the least concentration of 25.00% had a Reynolds number and fanning friction factor of 0.3314 and 0.5788. The fanning friction factor represents the disturbance, friction or turbulence along the export line and higher values represents higher drag and friction along the export line.
