The Effect of Surfactants on Vertical Air/Water Flow for Prevention of Liquid Loading

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 488-500 ◽  
Author(s):  
A. T. van Nimwegen ◽  
L. M. Portela ◽  
R. A. Henkes
Keyword(s):  
Surface Tension ◽  
Pressure Gradient ◽  
Water Flow ◽  
Annular Flow ◽  
Surfactant Concentration ◽  
Gas Flow ◽  
Liquid Loading ◽  
Dynamic Surface ◽  
Flow Rates ◽  
Churn Flow

Summary From field experience in the gas industry, it is known that injecting surfactants at the bottom of a gas well can prevent liquid loading. To better understand how the selection of the surfactant influences the deliquification performance, laboratory experiments of air/water flow at atmospheric conditions were performed, in which two different surfactants (a pure surfactant, sodium dodecyl sulfate, and a commercial surfactant blend) were added to the water. In the experiments, a high-speed camera was used to visualize the flow, and pressure-gradient measurements were performed. Both surfactants increase the pressure gradient at high gas-flow rates and decrease the pressure gradient at low gas-flow rates. The minimum in the pressure gradient moves to lower gas-flow rates with increasing surfactant concentration. This is related to the transition between annular flow and churn flow, which is shifted to lower gas-flow rates because of the formation of an almost stagnant foam substrate at the wall of the pipe. At high surfactant concentration, it appears that the churn flow regime is no longer present at all and that there is a direct transition from annular flow to slug flow. The results also show that the critical micelle concentration, the equilibrium surface tension, the dynamic surface tension, and the surface elasticity are poor predictors of the effect of the surfactant on the flow.

A Machine Learning Approach to Predict the Pressure Gradient of Different Oil-Water Flow Patterns in a Horizontal Wellbore

2021 ◽  
Author(s):  
MD Ferdous Wahid ◽  
Reza Tafreshi ◽  
Zurwa Khan ◽  
Albertus Retnanto
Keyword(s):  
Machine Learning ◽  
Surface Tension ◽  
Surface Roughness ◽  
Pressure Gradient ◽  
Water Flow ◽  
Flow Patterns ◽  
Data Driven ◽  
Pressure Gradients ◽  
Horizontal Wellbore ◽  
Oil Water

Abstract Fluid pressure gradient in a wellbore plays a significant role to efficiently transport between source and separator facilities. The mixture of two immiscible fluids manifests in various flow patterns such as stratified, dispersed, intermittent, and annular flow, which can significantly influence the fluid’s pressure gradient. However, previous studies have only used limited flow patterns when developing their data-driven model. The aim of this study is to develop a uniform data-driven model using machine-learning (ML) algorithms that can accurately predict the pressure gradient for the oil-water flow with two stratified and seven dispersed flow patterns in a horizontal wellbore. Two different machine-learning algorithms, Artificial Neural Network (ANN) and Random Forest (RF), were employed to predict the pressure gradients. A total of 662 experimental points from nine different flow patterns were extracted from five sources that include twelve variables for different physical properties of oil-water, wellbore’s surface roughness, and input diameter. The variables are entrance length to diameter ratio, oil and water viscosity, density, velocity, and surface tension, between oil and water surface tension, surface roughness, input diameter, and flow pattern. The algorithms’ performance was evaluated using median absolute percentage error (MdAPE) and root mean squared error (RMSE). A repeated train-test split strategy was used where the final MdAPE and RMSE were computed from the average of all repetitions. The MdAPE and RMSE for the prediction of pressure gradients are 13.89% and 0.138 kPa/m using RF and 12.17% and 0.088 kPa/m using ANN, respectively. The ML algorithms’ ability to model the pressure gradient is demonstrated using measured vs. predicted analysis where the experimental data points are mostly located in close proximity of the diagonal line, indicating a suitable generalization of the models. Comparing the performance between RF and ANN shows that the latter algorithm’s prediction accuracy is significantly better (p<0.01).

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.

Submerged Gas Injection in Microgravity

2002 ◽  
Author(s):  
J. Carrera ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Surface Tension ◽  
Weber Number ◽  
Gas Flow ◽  
Capillary Tube ◽  
Bubble Formation ◽  
Gas Injection ◽  
Flow Regimes ◽  
Flowing Liquid ◽  
Flow Rates ◽  
Reduced Surface

The effects of buoyancy on the flow regimes of submerged gas injection were studied in this investigation. A capillary tube submerged in water was used for gas injection in microgravity and terrestrial conditions, and the resulting flow regimes and bubble sizes were documented. The effects of liquid co-flow and reduced surface tension were also analyzed. Under reduced gravity, three flow regimes were observed over the range of conditions tested. At low gas flow rates, the bubbles did not detach from the injector, forming an interconnected bubble cluster that adhered to the injector. Single bubbles started detaching and moving away from the injector when the Weber number reached a value around 3. At gas flow rates corresponding to a Weber number value of 10, the bubble coalescence regime was observed near the injector. It was found that the absence of buoyancy prevented the formation of the jetting regime. For all gas throughputs, the co-flowing liquid aided the detachment of the bubbles, resulting in the generation of more uniform bubbles than in quiescent liquids. The presence of co-flow resulted in a smaller bubble size accompanied by an increased frequency of bubble formation. Reduced surface tension produced a similar effect, resulting in smaller bubbles.

Local Liquid Velocities in Horizontal, Annular Air/Water Flow

2003 ◽  
Author(s):  
Charles R. Kopplin
Keyword(s):  
Liquid Film ◽  
Water Flow ◽  
Measurement Method ◽  
Annular Flow ◽  
Current Data ◽  
Air Bubbles ◽  
Flow Modeling ◽  
Two Phase ◽  
Flow Rates ◽  
Film Distribution

A newly developed flow visualization method that utilizes a three color LED strobe has been used to study the axial and circumferential velocities of the liquid in horizontal, annular two-phase flow. This non-intrusive technique allows the tracking of naturally entertained air bubbles within the liquid film along the top, bottom, and sides of the tube. Sets of images have been obtained for multiple combinations of air and water flow rates ranging in quality from approximately 0.07 to 0.49. The bubble-tracking velocimetry measurement method is explained, and comparison of the current data with past results and their impact on annular flow modeling are discussed. The data do not support two of the four theories for liquid film distribution in annular, horizontal multiphase flow, while the two remaining theories cannot be directly examined using the three color LED strobe measurement technique.

Simultaneous gas and water flow in a damage-susceptible bedded argillaceous rock

2015 ◽  
Vol 52 (1) ◽  
pp. 18-32 ◽  
Author(s):  
T.S. Nguyen ◽  
A.D. Le
Keyword(s):  
Water Flow ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Gas Injection ◽  
Injection Pressure ◽  
Opalinus Clay ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Inherent Anisotropy

A mathematical model that couples the governing and constitutive equations of two-phase flow and mechanical equilibrium has been developed to simulate gas injection tests for both laboratory- and field-scale experiments. The model takes into consideration the inherent anisotropy of sedimentary rocks due to bedding by including an anisotropic elastoplastic model for the mechanical process and using an anisotropic permeability tensor for the flow processes for both water and gas. The gas and water flow rates are assumed to follow Darcy’s law. The relative permeability of each phase and their respective degrees of saturation are represented by the Van Genuchten’s functions. We simulated laboratory and field gas injection experiments in Opalinus clay, a candidate geological formation for the geological disposal of radioactive wastes. The numerical results show good agreement with the experimental data measured in these tests in terms of two-phase flow regimes and hydromechanical response at various monitoring locations. Damage zones, either pre-existing due to excavation or induced by high gas injection pressure, are shown to clearly influence the gas flow rates and directions and would need special consideration in the design and safety assessment of the repository system.

Oxygen Consumption and Gill Water Flow in the Dogfish Scyliorhinus Canicula L

1968 ◽  
Vol 49 (3) ◽  
pp. 557-564 ◽  
Author(s):  
G. M. HUGHES ◽  
SHUN-ICHI UMEZAWA
Keyword(s):  
Oxygen Consumption ◽  
Hydrostatic Pressure ◽  
Pressure Gradient ◽  
Linear Relationship ◽  
Water Flow ◽  
Marked Change ◽  
Respiratory Frequency ◽  
Flow Rates ◽  
Scyliorhinus Canicula ◽  
The Relationship

1. Determinations of the standard oxygen consumption of the dogfish Scyliorhinus canicula, by several different methods, gave values in the range of 20-55 c.c./kg./hr. at 12°C. 2. When the rate of water flow over the resting fish is increased, there is an increase in oxygen consumption, but no marked change in respiratory frequency at the flow rates studied. An increase of respiratory frequency took place when the PO2 of the inspired water was reduced. 3. The ventilation volume of the dogfish was measured by collecting the water in chambers after it had passed over the gills. The resting ventilation volume was about 120 c.c./min./kg. at 12° C. 4. The relationship between the flow across the gills and the imposed hydrostatic pressure gradient (Δp) showed a linear relationship. The fish was unable to continue pumping water across the gills against adverse gradients in excess of 0.7 cm. H2O. 5. When the flow across the gills was relatively low, utilization of oxygen of at least 70% was observed, but with increasing flow rates this fell to between 40 and 50%.

Experiments of Liquid Loading and Intermittent Production Using a Lab-Scale Reservoir-Tubing Setup

2021 ◽  
Author(s):  
Jos van 't Westende ◽  
Dries van Nimwegen ◽  
Stefan Belfroid ◽  
Harmen Slot
Keyword(s):  
Total Pressure ◽  
Gas Flow ◽  
Experimental Setup ◽  
Reservoir Model ◽  
Liquid Loading ◽  
Flow Rates ◽  
Pressure Losses ◽  
Set Up ◽  
Start Ups ◽  
Production Tubing

Abstract Experiments were performed to investigate the physics behind intermittent production and liquid loading, using a setup containing a reservoir model coupled to a vertical production tubing. In the experiments both gas and liquid are injected into the reservoir, which is a container in which sand with two different permeabilities is placed. Quick closing valves are incorporated into the experimental setup in order to simulate well shut-ins and start-ups. The experimental results show that the addition of the reservoir to the experimental set-up shifts the minimum in the total pressure losses over the system to lower gas flow rates as the permeability of the reservoir decreases. When performing shut-ins where a significant liquid column is present in the tubing, as is the case in liquid loaded wells, performing a sufficiently long shut-in can lead to the deliquification of the system.

Analysis of the Interchange Rate and Pressure Gradient of Annular Flow Based on a Probability Model

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Ri Zhang ◽  
Feng Zhang ◽  
Sheng Dong
Keyword(s):  
Pressure Gradient ◽  
Annular Flow ◽  
Phase Distribution ◽  
Probability Model ◽  
Interfacial Shear Stress ◽  
Flow Rates ◽  
Liquid Phases ◽  
Deposition Processes ◽  
Basic Equations ◽  
Relationship Of

The phase distribution and mechanical properties of annular flow have obvious, random characteristics because of the influence of turbulence. Thus, probability analysis is a suitable method for the study of annular flow. In the present work, the interchange rate and pressure gradient of fully developed annular flow are investigated in detail based on a probability model. The probability model tracks the atomization and deposition processes of a single particle to analyze the momentum and mass exchange between the gas and liquid phases. The interchange rate can be calculated by summing the generation or disappearance probability of droplets with different sizes. The pressure gradient can be obtained by solving the basic equations of the annular flow, which contains an improved relationship of interfacial shear stress. The predictions of the interchange rate and pressure gradient are well verified by comparison with experimental data available in the literature. Furthermore, the effects of the gas and liquid flow rates on the interchange rate and pressure gradient are discussed in detail.

Parametric Study of Churn Flow in Large Diameter Pipes

2014 ◽  
Author(s):  
Buddhika N. Hewakandamby ◽  
Aime U. Kanu ◽  
Barry J. Azzopardi ◽  
Gene Kouba
Keyword(s):  
Liquid Phase ◽  
Flow Rate ◽  
Annular Flow ◽  
Bubbly Flow ◽  
Large Diameter ◽  
Wire Mesh ◽  
Axial Distance ◽  
Phase Flow ◽  
Flow Rates ◽  
Churn Flow

Two phase flow in vertical risers are common place in oil and gas industry and many other process industries. Depending on the flow rates of the phases, there could be several flow patterns could exist inside the riser. These could vary from bubbly flow to annular flow with slug and churn flow in between. When the liquid phase flow rate is higher the bubbly flow exists while the annular flow is dominated by higher gas flow rate that forms a distinct gas core in the middle of the vertical riser. Of these flow regimes, churn flow is of particular interest as it is not well understood. The paper will report findings of an experimental campaign investigating the development of churn flow. Experiments were carried out in a closed loop flow facility with a 127 mm ID, 11 m long vertical test section. The maximum flow rates achievable in the system were 17 and 1.2 m/s for gas and liquid phases respectively. Compressed air was used as the gas phase while water and water/glycerol mixtures were used as the liquid phase. The mixtures of water and glycerol were used to investigate the influence of the viscosity on the flow regime investigated. The flow was investigated using a Wire Mesh Sensor (WMS), an intrusive measurement device that can map the cross sectional distribution of phases. Void fraction measurements were made at several axial locations for a number of flow rate combinations from onset of churn flow until it turns into annular flow. A region in flow rates where large liquid ligaments (wisps) suspended in the gas core was found and the breakup mechanism has been observed. Furthermore, huge waves were observed in this region. Analysis of results shows that the frequency of both huge waves and the wisps entrained in the gas core increase along the axial distance. The changes to the flow behaviour with the increase of viscosity and other findings will be presented in detail in the paper.

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