Effect of Drag-Reducing Agents in Multiphase Flow Pipelines

1998 ◽  
Vol 120 (1) ◽  
pp. 15-19 ◽  
Author(s):  
C. Kang ◽  
R. M. Vancko ◽  
A. S. Green ◽  
H. Kerr ◽  
W. P. Jepson
Keyword(s):  
Multiphase Flow ◽  
Pressure Gradient ◽  
Slug Flow ◽  
Annular Flow ◽  
Flow Regimes ◽  
Reducing Agents ◽  
Pressure Gradients ◽  
Horizontal Pipes ◽  
Flow Pressure ◽  
Inclined Pipes

The effect of drag-reducing agents (DRA) on pressure gradient and flow regime has been studied in horizontal and 2-deg upward inclined pipes. Experiments were conducted for different flow regimes in a 10-cm i.d., 18-m long plexiglass system. The effectiveness of DRA was examined for concentrations ranging from 0 to 75 ppm. Studies were done for superficial liquid velocities between 0.03 and 1.5 m/s and superficial gas velocities between 1 and 14 m/s. The results indicate that DRA was effective in reducing the pressure gradients in single and multiphase flow. The DRA was more effective for lower superficial liquid and gas velocities for both single and multiphase flow. Pressure gradient reductions of up to 42 percent for full pipe flow, 81 percent for stratified flow, and 35 percent for annular flow were achieved in horizontal pipes. In 2 deg upward inclination, the pressure gradient reduction for slug flow, with a concentration of 50 ppm DRA, was found to be 28 and 38 percent at superficial gas velocities of 2 and 6 m/s, respectively. Flow regimes maps with DRA were constructed in horizontal pipes. Transition to slug flow with addition of DRA was observed to occur at higher superficial liquid velocities.

Effect of Particle Size and Viscosity on Erosion in Annular and Slug Flow

2012 ◽  
Author(s):  
N. R. Kesana ◽  
J. M. Throneberry ◽  
B. S. McLaury ◽  
S. A. Shirazi ◽  
E. F. Rybicki
Keyword(s):  
Multiphase Flow ◽  
Electrical Resistance ◽  
Slug Flow ◽  
Annular Flow ◽  
Oil And Gas ◽  
Flow Regimes ◽  
Operating Conditions ◽  
Solid Particles ◽  
Metal Loss ◽  
Head Probe

Solid particle erosion is a mechanical process in which material is removed from a surface due to impacts of solid particles transported within a fluid. It is a common problem faced by the petroleum industry, as solid particles are also produced along with oil and gas. The erosion not only causes losses resulting from repairs and decreased production but also causes safety and environmental concerns. Therefore, the metal losses occurring in different multiphase flow patterns need to be studied and understood in order to develop protective guidelines for oil and gas production equipment. A large scale boom loop, which is capable of generating a wide variety of multiphase flow regimes was used for conducting experiments. Specifically, this work examines erosion measurements in multiphase slug and annular flow regimes. These flow regimes are selected since they produce higher metal losses than other flow regimes, and they also occur for a wide variety of operating conditions. Experiments are performed on a horizontal 0.0762 m (3-inch) diameter pipe, with superficial gas velocities ranging from 15.2 m/s (50 ft/s) to 45.7 m/s (150 ft/s) and superficial liquid velocities ranging from 0.46 m/s (1.5 ft/s) to 0.76 m/s (2.5 ft/s), for liquid viscosities of 1 cP and 10 cP. Carboxymethyl Cellulose (CMC) was used to increase the viscosity of the liquid without significantly altering the density of the liquid. Three different sand sizes (20, 150 and 300 micron sand) were used for performing tests. The shapes of the sand are also different with the 20 and 300 micron sand being sharper than the 150 micron sand. Erosion measurements are taken using Electrical Resistance (ER) probes which relate the change in electrical resistance to the change in the thickness of an exposed element resulting from erosion. Two probes are placed in a bend and another probe is placed in a straight section of pipe. The probes in the bend are flat-head probes, and they are placed flush with the outer wall in the 45 and 90 degree positions. The probe in the straight pipe is an angle-head probe which protrudes into the flow with the face placed in the center of the pipe. Under the flow conditions investigated, the angle-head probe measures the maximum erosion due to its placement. Results demonstrate a significant increase in the metal loss occurs when increasing the superficial gas velocity and decreasing the superficial liquid velocity. The effect of changing the viscosity of the liquid is not as clear. Results suggest a slight increase in metal loss by increasing the viscosity from 1cP to 10 cP in slug flow. However, for annular flow, higher erosion occurs for the lower liquid viscosity considered.

Pressure Drop During Condensation in Microchannels

2012 ◽  
Author(s):  
H. S. Wang ◽  
J. W. Rose
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Void Fraction ◽  
Annular Flow ◽  
Pressure Gradients ◽  
Flow Solution ◽  
Approximate Models ◽  
Significant Difference ◽  
Friction Pressure ◽  
Flow Pressure

The paper examines the special case of annular laminar flow pressure drop, or more precisely pressure gradient, during condensation in microchannels. This is the only flow regime permitting wholly theoretical solution without having recourse to experimental data. Solutions are obtained and comparisons made with empirical formulae for void fraction (needed to calculate the momentum pressure gradient) when obtaining the friction pressure gradient from experimentally measured or “total” pressure gradient. To date calculations and comparisons are restricted to one fluid (R134a), one channel section and one flow condition. For the case considered it is found that earlier approximate models for estimating void fraction agree quite well with the theoretical annular flow solutions. There is, however, significant difference between momentum pressure gradients obtained from approximate models used in the earlier investigations and that given by the theoretical annular flow solution which is (numerically) higher than all of them. The annular flow solution indicates that the momentum pressure gradient is not small in comparison with the friction pressure gradient. The friction pressure gradient in the annular flow case is appreciably smaller than given by the earlier correlations.

A Novel Two-Phase Gas\Liquid Slug Flow Measurement System Using a T-Junction Separator and Ultrasonic Measurements

2008 ◽  
Author(s):  
Khalifa M. Khalifa ◽  
Mike L. Sanderson
Keyword(s):  
Multiphase Flow ◽  
Systems Engineering ◽  
Measurement System ◽  
Slug Flow ◽  
Flow Measurement ◽  
Cross Correlation ◽  
Flow Regimes ◽  
Oil And Gas Industry ◽  
Wide Range ◽  
Ultrasonic Measurements

Over the last decade, the development and deployment of in-line multiphase flow metering systems has been a major focus worldwide. Accurate measurement of multiphase flow in the oil and gas industry is difficult because it occurs in wide range of flow regimes and multiphase meters do not generally perform well under the intermittent slug flow conditions which commonly occur in oil production. A novel ultrasonic multiphase metering concept has been proposed and investigated which measures the flow rates of the liquid and gas phases from ultrasonic measurements made in two different flow regimes – partially separated and homogeneous — in the same measurement system and fuses the data from the different flow regimes to obtain improved overall measurement accuracy. The system employs a partial gas/liquid separation using a T-junction configuration and a combination of Doppler and cross correlation. The partially separated flow regimes uses ultrasonic cross correlation measurement for the liquid flow measurement which has gas entrained within it. The homogeneous regime employs ultrasonic Doppler method. This approach has been tested on water/air flows on a 50mm facility in the Department of Process and Systems Engineering. The liquid and gas flowrate measurements using the proposed techniques were compared with a reference measurement and good agreements between these two measurements were obtained with error ranging from ± 2% and 10%, respectively. Such a performance offers the potential for an in-line multiphase flowmeter with improved performance.

CFD Simulation of Two-Phase Vertical Annular Flow in Both Upward and Downward Direction in a Small Pipe

2019 ◽  
Author(s):  
Ekhwaiter Abobaker ◽  
Abadelhalim Elsanoose ◽  
John Shirokoff ◽  
Mohammad Azizur Rahman
Keyword(s):  
Film Thickness ◽  
Multiphase Flow ◽  
Pressure Gradient ◽  
Annular Flow ◽  
Cfd Simulation ◽  
Flow Direction ◽  
Flow Behavior ◽  
Two Phase ◽  
Downward Flow ◽  
Disturbance Wave

Abstract Computational fluid dynamics (CFD) simulation is presented to investigate the annular flow behavior in the vertical pipe by using ANSYS Fluent platform 17.2. The study was analyzed complex behavior of annular flow in two cases (upward and downward flow) for different air superficial velocities and range of Reynolds number for water, in order to obtain the effect of orientation flow and increasing superficial gas and liquid velocities on the base film, mean disturbance wave thickness, the average longitudinal size of disturbance wave as well as pressure gradient. For multiphase flow model, the volume of fluid method (VOF) for two-phase flow modelling was used and coupled with RNG k-ε turbulence model to predict fully annular flow structures in the upward and downward flow direction. From CFD simulation results, it is clear to see how increases in air velocity result in reductions in film thickness and increase in pressure gradient. Additionally, the results showed monotonic enhancement of film thickness occurring in tandem with increases in the liquid flow rate. However, due to the effect of gravitational force and interfacial friction, the film thickness and pressure gradient are slightly larger for the upward flow than for the downward flow. The results agree with the recent experimental data that studied the annular flow behavior and pressure drop in the upward and downward flow direction. This study will be very helpful in understanding multiphase flow behavior in natural gas wells.

Comparison of the Performance of Drag Reducing Agent Between 2.5 cP Oil and 6.0 cP Oil in Multiphase Flow in Horizontal Pipes

2001 ◽  
Author(s):  
C. Kang ◽  
W. P. Jepson
Keyword(s):  
Pressure Drop ◽  
Multiphase Flow ◽  
Gas Phase ◽  
Annular Flow ◽  
Experimental Studies ◽  
Reducing Agent ◽  
Average Pressure ◽  
Flow Loop ◽  
Oil Viscosity ◽  
Horizontal Pipes

Abstract Experimental studies have been performed in a 10 cm diameter, 36 m long, multiphase flow loop to examine the effect of drag reducing agents using 6 cP oil. Studies were performed for superficial liquid velocities of 0.5, 1.0 and 1.5 m/s and superficial gas velocities between 2 and 12 m/s. Carbon dioxide was used as the gas phase. The drag reducing agent (DRA) concentrations were 20 and 50 ppm. The system was maintained at a pressure of 0.13 MPa and a temperature of 25 °C. The comparison of the conditioning of flow with DRA between 2.5 cP oil and 6 cP oil is presented. The results show that pressure drop in both 2.5 cP oil and 6 cP oil was reduced significantly in multiphase flow with addition of DRA. A DRA concentration of 50 ppm was more effective than 20 ppm DRA for all cases. As the oil viscosity was increased from 2.5 cP to 6 cP oil, the transition to annular flow was observed to occur at lower superficial gas velocities. For slug flow and lower superficial gas velocities, the effectiveness in 2.5 cP oil was much higher than that in 6 cP oil with addition of DRA. However, for higher superficial gas velocities, the effectiveness in both oils was similar. For annular flow, the effectiveness in 2.5 cP oil was higher than in 6 cP oil with 50 ppm DRA. At low superficial gas velocities, DRA in 2.5 cP oil was more effective in reducing the slug frequency. This led to a higher average pressure drop reduction in 2.5 cP oil. However, at higher superficial gas velocities, the slug frequency decreased in both oils almost the same magnitude.

Pressure Effects on Low-Liquid-Loading Oil/Gas Flow in Slightly Upward Inclined Pipes: Flow Pattern, Pressure Gradient, and Liquid Holdup

SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 2221-2238 ◽  
Author(s):  
Hendy T. Rodrigues ◽  
Eduardo Pereyra ◽  
Cem Sarica
Keyword(s):  
Pressure Gradient ◽  
Flow Pattern ◽  
Slug Flow ◽  
Annular Flow ◽  
Flow Patterns ◽  
Pressure Effects ◽  
Liquid Holdup ◽  
Liquid Loading ◽  
Interfacial Roughness ◽  
Oil Gas

Summary This paper studied the effects of system pressure on oil/gas low–liquid–loading flow in a slightly upward inclined pipe configuration using new experimental data acquired in a high–pressure flow loop. Flow rates are representative of the flow in wet–gas transport pipelines. Results for flow pattern observations, pressure gradient, liquid holdup, and interfacial–roughness measurements were calculated and compared to available predictive models. The experiments were carried out at three system pressures (1.48, 2.17, and 2.86 MPa) in a 0.155–m–inside diameter (ID) pipe inclined at 2° from the horizontal. Isopar™ L oil and nitrogen gas were the working fluids. Liquid superficial velocities ranged from 0.01 to 0.05 m/s, while gas superficial velocities ranged from 1.5 to 16 m/s. Measurements included pressure gradient and liquid holdup. Flow visualization and wire–mesh–sensor (WMS) data were used to identify the flow patterns. Interfacial roughness was obtained from the WMS data. Three flow patterns were observed: pseudo-slug, stratified, and annular. Pseudo-slug is characterized as an intermittent flow where the liquid does not occupy the whole pipe cross section as does a traditional slug flow. In the annular flow pattern, the bulk of the liquid was observed to flow at the pipe bottom in a stratified configuration; however, a thin liquid film covered the whole pipe circumference. In both stratified and annular flow patterns, the interface between the gas core and the bottom liquid film presented a flat shape. The superficial gas Froude number, FrSg, was found to be an important dimensionless parameter to scale the pressure effects on the measured parameters. In the pseudo-slug flow pattern, the flow is gravity–dominated. Pressure gradient is a function of FrSg and liquid superficial velocity, vSL. Liquid holdup is independent of vSL and a function of FrSg. In the stratified and annular flow patterns, the flow is friction–dominated. Both pressure gradient and liquid holdup are functions of FrSg and vSL. Interfacial–roughness measurements showed a small variation in the stratified and annular flow patterns. Model comparison produced mixed results, depending on the specific flow conditions. A relation between the measured interfacial roughness and the interfacial friction factor was proposed, and the results agreed with the existing measurements.

scholarly journals Engineering Simulation Tests on Multiphase Flow in Middle- and High-Yield Slanted Well Bores

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2591 ◽  
Author(s):  
Dan Qi ◽  
Honglan Zou ◽  
Yunhong Ding ◽  
Wei Luo ◽  
Junzheng Yang
Keyword(s):  
Multiphase Flow ◽  
Prediction Model ◽  
Flow Pattern ◽  
Pipe Flow ◽  
Slug Flow ◽  
High Yield ◽  
Transition Flow ◽  
Liquid Holdup ◽  
Flow Pattern Map ◽  
Flow Pressure

Previous multiphase pipe flow tests have mainly been conducted in horizontal and vertical pipes, with few tests conducted on multiphase pipe flow under different inclined angles. In this study, in light of mid–high yield and highly deviated wells in the Middle East and on the basis of existent multiphase flow pressure research on well bores, multiphase pipe flow tests were conducted under different inclined angles, liquid rates, and gas rates. A pressure prediction model based on Mukherjee model, but with new coefficients and higher accuracy for well bores in the study block, was obtained. It was verified that the newly built pressure drawdown prediction model tallies better with experimental data, with an error of only 11.3%. The effect of inclination, output, and gas rate on the flow pattern, liquid holdup, and friction in the course of multiphase flow were analyzed comprehensively, and six kinds of classical flow regime maps were verified with this model. The results showed that for annular and slug flow, the Mukherjee flow pattern map had a higher accuracy of 100% and 80–100%, respectively. For transition flow, Duns and Ros flow pattern map had a higher accuracy of 46–66%.

Pressure Drop During Condensation in Microchannels

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Hua Sheng Wang ◽  
Jie Sun ◽  
John W. Rose
Keyword(s):  
Experimental Data ◽  
Pressure Gradient ◽  
Void Fraction ◽  
Annular Flow ◽  
Gradient Methods ◽  
Pressure Gradients ◽  
High Quality ◽  
Friction Pressure ◽  
Flow Condensation ◽  
Approximate Equations

The paper reports calculations of friction pressure gradient for the special case of laminar annular flow condensation in microchannels. This is the only flow regime permitting theoretical solution without having recourse to experimental data. Comparisons are made with correlations based on experimental data for R134a. The correlations differ somewhat among themselves with the ratio of highest to lowest predicted friction pressure gradient typically around 1.4 and nearer to unity at high quality. The friction pressure gradients given by the laminar annular flow solutions are in fair agreement with the correlations at high quality and lower than the correlations at lower quality. Attention is drawn to the fact that the friction pressure gradient cannot be directly observed and its evaluation from measurements requires estimation of the nondissipative momentum or acceleration pressure gradient. Methods used to estimate the nondissipative pressure gradient require quality and void fraction together with equations which relate these and whose accuracy is difficult to quantify. Quality and void fraction can be readily found from the laminar annular flow solutions. Significant differences are found between these and values from approximate equations.

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