Viscous oil–water flows in a microchannel initially saturated with oil: Flow patterns and pressure drop characteristics

The flow characteristics of a highly viscous oil and water mixture in a circular microchannel have been investigated. Water and silicone oil with a viscosity of 863 mPa.s were injected into a fused silica microchannel with a diameter of 250 μm. Before each experiment, the microchannel was initially saturated with either oil or water. In the initially oil-saturated case, different liquid-liquid flow patterns were observed and classified over a wide range of oil and water flow rates. As a special case, the flow of water at zero oil flow rate in a microchannel initially filled with silicone oil was also studied. When the microchannel was initially saturated with water, the oil formed a jet in water at the injection point but developed an instability at the oil-water interface downstream and eventually broke up into droplets.

Download Full-text

Drag Reduction with Biopolymer-Synthetic Polymer Mixtures in Oil-Water Flows: Effect of Synergy

Engineering Journal ◽

10.4186/ej.2020.24.6.1 ◽

2020 ◽

Vol 24 (6) ◽

pp. 1-10

Author(s):

Lawrence Chukwuka Edomwonyi-Otu ◽

Muhammed Muhammed Gimba ◽

Nurudeen Yusuf

Keyword(s):

Reynolds Number ◽

Pressure Drop ◽

Pressure Gradient ◽

Drag Reduction ◽

Water Flow ◽

Transport Systems ◽

Test Fluid ◽

Polymer Mixture ◽

Water Flows ◽

Oil Water

The search for lower cost materials that reduce pressure drop in fluid transport systems in oil and gas industries to conserve pumping energy is of paramount importance. Polymers are known to reduce pressure drop in pipeline oil-water flows in a process referred to as drag reduction (DR). The effect of partially hydrolysed polyacrylamide, polyethylene oxide, Aloe Vera mucilage and their mixtures as drag reducing polymers (DRPs) on pressure gradient (pressure drop; Δp) in pipeline oil-water flows were studied. The experiment was carried out in flow rig with 0.02-m diameter straight unplasticised polyvinylchloride (uPVC) pipe, two centrifugal pumps, control valves and two storage tanks. Tap water (ρ = 997 kg/m3 and µ = 0.89 cP) and diesel (ρ = 832 kg/m3 and µ = 1.66 cP) were used as the test fluid at ambient condition. The polymer mixture total concentration (MTC) of 30 and 400 ppm at different mixing proportion, mixture Reynolds number (Remix) and oil input volume were investigated. The results show increase in pressure gradient with increase in oil input volume in both single-phase water flow and oil-water flow before adding drag reducing polymers (DRPs). However, Δp decreased after adding DRPs with increase in Reynolds number (Re) or Remix and decrease in the oil-phase Re, and vice versa. The results further showed higher reduction in pressure drop by the polymer mixture than in each of the polymer used at the same conditions. The rigidness of the biopolymer was improved by adding synthetic polymers which resulted to increase in DR efficiency.

Download Full-text

Prediction of pressure drop for segregated oil-water flows in small diameter pipe using modified two-fluid model

Experimental Thermal and Fluid Science ◽

10.1016/j.expthermflusci.2020.110078 ◽

2020 ◽

Vol 114 ◽

pp. 110078

Author(s):

Lusheng Zhai ◽

Hongxin Zhang ◽

Ningde Jin

Keyword(s):

Pressure Drop ◽

Fluid Model ◽

Small Diameter ◽

Water Flows ◽

Diameter Pipe ◽

Oil Water ◽

Two Fluid Model ◽

Two Fluid

Download Full-text

Investigation of Holdup and Pressure Drop Behavior for Oil-Water Flow in Vertical and Deviated Wells

Journal of Energy Resources Technology ◽

10.1115/1.2795016 ◽

1998 ◽

Vol 120 (1) ◽

pp. 8-14 ◽

Cited By ~ 20

Author(s):

J. G. Flores ◽

C. Sarica ◽

T. X. Chen ◽

J. P. Brill

Keyword(s):

Pressure Drop ◽

Water Flow ◽

Flow Patterns ◽

Production Optimization ◽

Pressure Gradients ◽

Two Phase ◽

Drift Flux Model ◽

Drift Flux ◽

Inclination Angles ◽

Oil Water

Two-phase flow of oil and water is commonly observed in wellbores, and its behavior under a wide range of flow conditions and inclination angles constitutes a relevant unresolved issue for the petroleum industry. Among the most significant applications of oil-water flow in wellbores are production optimization, production string selection, production logging interpretation, down-hole metering, and artificial lift design and modeling. In this study, oil-water flow in vertical and inclined pipes has been investigated theoretically and experimentally. The data are acquired in a transparent test section (0.0508 m i.d., 15.3 m long) using a mineral oil and water (ρo/ρw = 0.85, μo/μw = 20.0 & σo−w = 33.5 dyne/cm at 32.22°C). The tests covered inclination angles of 90, 75, 60, and 45 deg from horizontal. The holdup and pressure drop behaviors are strongly affected by oil-water flow patterns and inclination angle. Oil-water flows have been grouped into two major categories based on the status of the continuous phase, including water-dominated and oil-dominated flow patterns. Water-dominated flow patterns generally showed significant slippage, but relatively low frictional pressure gradients. In contrast, oil-dominated flow patterns showed negligible slippage, but significantly large frictional pressure gradients. A new mechanistic model is proposed to predict the water holdup in vertical wellbores based on a drift-flux approach. The drift flux model was found to be adequate to calculate the holdup for high slippage flow patterns. New closure relationships for the two-phase friction factor for oil-dominated and water-dominated flow patterns are also proposed.

Download Full-text