Three-phase Flow Patterns Research Articles

Study of the flow pattern and pressure drop law of the air-water-foam three-phase flow

The inaccurate prediction of flow patterns and pressures after adding different types and concentrations of surfactants to wellbores and drainage lines is a common problem in shale gas wells and tubing foam drainage. To clarify the change rule of the air–water-foam three-phase flow pattern and pressure drop after adding different types and concentrations of surfactants, a surface tension test was conducted in this study. In addition, visual air–water-foam three-phase flow indoor simulation experiments were performed with various surfactants such as cocamidopropyl hydroxysulfobetaine (MX-1), dodecyldimethyl betaine (TCJ-1), and sodium α-alkenyl sulfonate (XJHSM), surfactant concentrations (0.3–0.6 %), oil pipe diameters, pipe inclinations, gas–liquid ratios, and oil contents on large-scale experimental equipment. Based on the gas–liquid distribution characteristics, the air–water-foam three-phase flow patterns in the inclined tube were reclassified, and the quantitative conversion boundaries of the various flow patterns were determined. Based on the pressure drop pulse characteristics, characterization parameters such as the scaling factor, foaming capacity, foam density, and gas-holding rate were introduced after considering the effects of various factors on the pressure drop weights, enabling a new pressure drop calculation method for air–water-foam three-phase flows for application to different types and concentrations of surfactants. The errors were verified using data from previous studies and field measurements that were within 15% and 5%, respectively. The results of these studies provide a better understanding of the air–water-foam three-phase flow patterns and pressure drop variations in shale gas wells and gathering lines.

Oil–Gas–Water Three-Phase Flow Pattern Identification Through Parallel Decision Trees With Differential Pressure and Ultrasonic Sensors

Oil–Gas–Water Three-Phase Flow Pattern Identification Through Parallel Decision Trees With Differential Pressure and Ultrasonic Sensors

Dimensionless Analyses of Liquid–Liquid–Liquid Three-Phase Flow Patterns in a Confined Microchannel

Dimensionless Analyses of Liquid–Liquid–Liquid Three-Phase Flow Patterns in a Confined Microchannel

Eulerian–Lagrangian modeling of spray G atomization with focus on vortex evolution and its interaction with cavitation

Internal flow is closely related to energy consumption and emissions because of its dominant role in the atomization process. The intricate three-phase flow patterns in an orifice were studied based on modified cavitation and turbulence models. Interacting vorticities and their interactions with cavitation were analyzed using vorticity identification methods and the vorticity transport equation. The paired vortex was formed before cavitation inception, and the cavitation inception occurred invariably inside the vortex core, indicating that cavitation was triggered by vortex evolution. Cavitation patterns affect the vorticity transport that further affects atomization. The internal flow data were then extracted and coupled to a hybrid break-up model with finer characteristic scales.The spray morphologies of different types of fuel at various operating conditions were obtained using diffused back illumination method to validate the proposed model. The predictions obtained from the coupled model were consistent with experimental results, exhibiting less dependence on the grid at the same time. The results of this study can supplement experimental measurements to explore the correlation between cavitation-modulated vortex transport and spray behavior.

Three-Phase Flow Tomography System in Upward-Vertical High-Viscous-Oil/Water/Gas Flow

A new three-phase flow tomography system is presented in this work. The system was developed to be applied in high-viscous-oil/water/gas flow arranged in different flow patterns, with the three fluids present simultaneously in a crossing point. The primary measurement is based on a simpler and reliable digital in-phase/quadrature (IQ) demodulator and a wire-mesh sensor (WMS), but the system is capable of including different types of primary measurements. Dynamic three-phase flow tests were carried out to verify the system performance and compare its results with the ones obtained by quick-closing valves (QCVs) and a high-speed video camera. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In situ</i> volumetric fractions and flow patterns were compared. The experiments were conducted in a vertical glass pipe of 50-mm i.d. and 12-m height. The observed three-phase flow patterns were water-continuous churn flow with dispersed bubbles and oil drops (WChBoDo), water-continuous slug flow with Taylor bubbles, spherical bubbles, and oil drops (WPiBoDo), and oil-continuous slug flow with Taylor bubbles, spherical bubbles, and water drops (OPiBoDi). Compared with the measurements using QCVs, the average relative errors of the measured volumetric phase fractions were 12% for water, 13% for air, and 22% for oil. The experimental results, including the details of the flow inside the pipe, the phase distributions, and the objective characterization of flow patterns, suggest that the proposed system is a promising option for three-phase flow-related studies and developments. The proposed technique can reach 8930 frames/s with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$16\times16$ </tex-math></inline-formula> WMS.

Flow rate measurement of oil-gas-water wavy flow through a combined electrical and ultrasonic sensor

Water-based dispersed wavy flow, whereby the water with dispersed oil droplets moves along the bottom of the pipe and the gas concurrently on the top, is a frequently encountered horizontal oil-gas-water three-phase flow pattern in petroleum production and transportation. Accurate flow metering of each individual phase is significant to academic research and industrial flow assurance. Therefore, we present a combined electrical and ultrasonic sensor to simultaneously and non-intrusively acquire online flowing information. This information includes: the water fraction estimated by the normalized voltage from a conductance sensor, the gas fraction calculated by locating the gas-liquid interface through a pulse-wave ultrasonic sensor consisting of three transducers, and the coupled velocity of oil droplets and gas-liquid interface from Doppler shift signal acquired by a continuous wave ultrasonic Doppler sensor. Based on the limited flowing information obtained by multimodality sensors, a novel theoretical model is established based on the analysis of the momentum balance between different phases to solve phase fractions and phase actual velocities for calculating phase flow rates. To make the model closed and solvable, the interfacial velocity and oil velocity are respectively extracted by decoupling the Doppler shift signal through amplitude-aware permutation entropy and noise assisted multivariate empirical mode decomposition methods. Finally, the phase flow rates are calculated by the solutions of the established model. Dynamic experiments are performed to verify the effectiveness and accuracy of the proposed method and theoretical model. This study could provide a potential solution for non-intrusive phase flow metering of industrial three phase flow.

Flow pattern identification and measurement techniques in gas-liquid-liquid three-phase flow: A review

The simultaneous flow of gas, oil, and water forms various flow patterns due to the complex interfacial relationships. Three-phase flow patterns are classified as the gas-liquid and liquid-liquid flow patterns. Pressure drop, void fraction, liquid holdup, and phase distribution are important characteristics of the three-phase flow. These characteristics are generally associated with the three-phase flow patterns. Hence, the knowledge about flow patterns can help to predict the overall behavior of the three-phase flow. Studies have been conducted to identify three-phase flow pattern and their characteristics at various superficial velocities of gas, oil, and water. The major purpose of the studies is to gather information about the three-phase co-current flow and use it for improvement of the efficiency of the flow systems. Therefore, the accuracy of the measurement technique is critical. Several types of flow pattern identification and measurement techniques have been developed to improve accuracy and provide high-quality results. In this article, classical and advanced techniques used for the three-phase flow identification and measurement have been reviewed. The survey will help the researchers working in the area of multiphase flow to choose the right technique based on the objectives of the studies.

Experimental study on gas-liquid-liquid three-phase flow patterns and the resultant pressure drop in a horizontal pipe upstream of the 90° bend

The use of 90˚ bend for diversion of flow in different orientations is widespread. The current study is focused on the effect of 90˚ bend on gas-oil–water three-phase flow in an upstream horizontal pipe. The diameter of the test section is 0.1524 m, and (R/d) ratio of the bend is 1. The ranges of superficial velocities of gas, oil, and water were 0.5–5, 0.08–0.36, and 0.08–0.36 m/s, respectively. The observed gas–liquid flow patterns are slug, pseudo-slug, stratified wavy, stratified roll wave, and stratified flow. The oil and water were observed to be flowing as a separate, partially mixed, and fully mixed liquid. Flow regime maps have been plotted to analyze the transition of flow patterns. The variation in pressure drop with the flow patterns has been studied. The experimental data has been used to develop pressure drop prediction correlation and the comparison with experimental results showed good agreement.

Review on gas–liquid–liquid three–phase flow patterns, pressure drop, and liquid holdup in pipelines

Gas–liquid–liquid three–phase co-current flow commonly occurs in the oil & gas production pipelines. The dynamics of three-phase flow are more complex than single and two-phase flow. High pressure drop and liquid holdup are common flow assurance problems in the upstream oil and gas production pipelines. These problems increase the energy consumption of the flow system, especially in the process of enhanced oil recovery (EOR). Three-phase flow behavior is highly dependent on the flow patterns. For an economical and energy-efficient production process, the flow pattern with less pressure drop and liquid holdup needs to be identified. In this article, three-phase flow patterns’ classification and structures are critically reviewed and discussed in detail. Flow regime transition with the change in volumetric fractions and superficial velocities of phases are also elaborated. The prediction models for flow regime transition and stability, pressure drop, liquid holdup, and three-phase flow characteristics are presented.

A new method of measuring the oil–air–water three-phase flow rate

Oil–air–water three-phase flow patterns in small-diameter vertical measurement channels are complex, making it difficult to establish techniques for interpretation of logging information. In this study, dynamic experiments involving oil–air–water three-phase flows were performed using a novel production logging tool that combined a petal-type turbine flowmeter, a conductance sensor, and an optical fiber sensor in a simulation well. Sensor response characteristics were researched, and a new method of measuring the oil–air–water three-phase flow rate was proposed. The measurement range and resolution of the gas flow rate were 3–20 and 1 m3/d, respectively, and the relative error range of gas flow rate interpretation was 5–10%. The measurement range and relative interpretation error range of the total liquid flow rate were 10–60 m3/d and 5–10%, respectively. The measurement range and resolution of the water cut were 50–100% and 2%, respectively. The absolute error range of interpretation of the water cut ranged from 3.2% to 5%. Currently, the technique is valid for laboratory use under ideal conditions.

CFD simulations of gas-liquid-liquid three-phase co-current flow in horizontal pipe by tracking volume fractions using VOF model

The gas-liquid-liquid three-phase co-current flow is frequently observed in upstream petroleum pipelines. The identification of three-phase flow patterns is important to characterize three-phase flow dynamics. The three-phase flow patterns change with the pipe diameter, superficial velocities and physical properties of the fluids. Computational fluid dynamics (CFD) analysis of three-phase flow through 0.1524 m diameter and 3.5 m long horizontal pipe has been conducted. The superficial velocity ranges of gas-oil-water were 0.5-4, 0.08-0.32 and 0.08-0.32 m/s respectively. The volume of fluid (VOF) model was used to simulate the three-phase interfacial structures. According to the results, the three-phase flow patterns have been successfully simulated. Three-phase flow regime map has been constructed to analyze the flow pattern transition with the superficial velocities. The three-phase flow pressure drop increased with the superficial velocities of oil and water. However, the drop in pressure first increased and then decreased with the increase in superficial velocity of the gas.

CFD Simulation of flow pattern in a bubble column reactor for forming aerobic granules and its development

ABSTRACTThe flow pattern is considered to play an important role in the formation of aerobic granular sludge in a bubble column reactor; therefore, it is necessary to understand the behavior of the flow in the reactor. A three-dimensional computational fluid dynamics (CFD) simulation for bubble column reactor was established to visualize the flow patterns of two-phase air–liquid flow and three-phase air–liquid-sludge flow under different ratios of height to diameter (H/D ratio) and superficial gas upflow velocities (SGVs). Moreover, a simulation of the three-phase flow pattern at the same SGV and different characteristics of the sludge was performed in this study. The results show that not only SGV but also properties of sludge involve the transformation of flow behaviors and relative velocity between liquid and sludge. For the original activated sludge floc to cultivate aerobic granules, the flow pattern has nothing to do with sludge, but is influenced by SGV, and the vortices is occurred and the relative velocity is increased with an increase in SGV; the two-phase flow can simplify the three-phase flow that predicts the flow pattern development in bubble column reactor (BCR) for aerobic granulation. For the aerobic granules, the liquid flow behavior developed from the symmetrical circular flow to numbers and small-size vortices with an increase in the sludge diameter, the relative velocity is amount up to ur = 5.0, it is 29.4 times of original floc sludge.

Analysis of vertical upward oil-gas-water three-phase flow based on multi-scale time irreversibility

Based on the measurement signals obtained from oil-gas-water three-phase flow experiments, multi-scale time irreversibility is investigated to characterize the dynamic behavior of different flow patterns. Firstly, the conductance fluctuation signals of oil-gas-water three-phase flow in the vertical upward pipe are collected. Subsequently, three typical flow patterns, i.e., oil in water-type bubble flow, oil in water-type transition flow and oil in water-type slug flow, are defined and analyzed. Using multi-scale time irreversibility index and the surrogate data approach, multi-scale time irreversibility can be detected from the collected signals with different flow patterns. Furthermore, in order to quantitatively characterize the time irreversibility of oil-gas-water three-phase flow, a novel criterion, i.e., Average value of Asymmetric Distance (AAD), is proposed in this paper. The proposed criterion is validated by the experiments. The experiment results show that the conductance signals acquired from different typical flow patterns of oil-gas-water three-phase flow have different time irreversibility. The AAD value obtained for the oil in water-type slug flow is larger than the AAD value obtained for the oil in water-type transition flow, and the AAD value obtained for the oil in water-type transition flow is larger than the AAD value obtained for the oil in water-type bubble flow. In addition, the mechanism leading to the formation of time irreversibility is further explored in terms of adaptive optimal kernel time-frequency representation. It is proved that AAD can be used to reveal the characteristics of asymmetry in the evolution of oil-gas-water three-phase flow pattern. The utilization of AAD will provide an important reference for characterization and analysis of the non-linear dynamic characteristics of oil-gas-water three-phase flow regime evolution in real applications.

Three-phase gas-oil-water flow in undulating pipeline

Three-phase gas-oil-water (G-O-W) is common in wells and pipelines producing from mature reservoirs, imposing serious flow assurance problems. Therefore, prediction of flow behavior and characteristics is critical for optimal and sustainable production. In this study, experimental three-phase G-O-W slug flow in undulating pipelines were acquired and analyzed with respect to average liquid holdup, phase distributions and slug characteristics. The slug characteristics considered in this study include, translational velocity, slug length and frequency along the system. The objective of this study is to experimentally investigate the slug flow characteristics to improve the current understanding of G-O-W flow behavior in undulating pipelines and the effect of water cut on slug flow characteristics. Further objective is to modify and validate an in-house two-phase flow simulator and commercial transient multiphase flow simulator OLGA™ with the experimental data. This study contributes to the improvement of the existing slug tracking models and the development of new models for the proper design and safe operation of three-phase flow in pipeline systems.Several results have been found in this study, for example, seven three-phase slug flow patterns were identified based on oil-water mixture in the upstream horizontal section of the undulating pipe section. These flow patterns were analyzed and compared with slug dissipation in the downhill section of the undulating pipe section. When these flow patterns were compared with two-phase slug dissipation behavior, no water cut effect was observed. For moderate and high flow rates, slugs with different oil-water mixing status had differences in slug frequencies and lengths. However, the evolution of liquid slug length distributions for 20% and 80% water cuts in the upstream horizontal section and upward inclined section did not show any significant dependence on water cut.Furthermore, the modified in-house two-phase model predicted the slug flow evolution along the undulated pipeline with a reasonable accuracy. OLGA™ predictions of average total liquid and water holdups, slug frequency and length data showed a fair match especially with the high flow-rate conditions. The models validation study shows that the effect of water cut on slug flow evolution in undulating pipelines was limited to the effect on dispersion characteristics.

Experimental investigation of air‐water‐oil three‐phase flow patterns in inclined pipes

Experiments of air-water-oil three-phase flow pattern is investigated in a 20mm diameter inclined pipe with a length of 6m using a high speed digital camera. The superficial velocities are in the range of 0.25–3m/s, 0.25–2.3m/s, and 0.08–13m/s for water, low viscosity oil and air, respectively. For describing flow patterns in three-phase flow, two parameters are considered: Interaction of gas and liquids mixture, and interaction of water and oil phases. The flow patterns for different pipe angles are discussed. Observed flow patterns are stratified-oil/water (or water/oil), wavy-stratified-o/w, bubbly-o/w, slug-o/w, plug-o/w, plug-stratified and annular-o/w. Major flow patterns for upward and downward pipe are slug-o/w and wavy-stratified-o/w, respectively. Also the effects of inclination angle varying from −45° to +45° and different oil cuts on flow patterns have been studied. The results show that by increasing the oil cut for different inclination angles, bubbly region extends and plug region becomes smaller.

Nonlinear multi-scale dynamic stability of oil–gas–water three-phase flow in vertical upward pipe

Characterizing stability and nonlinearity underlying oil–water–gas three-phase flow is a challenging problem of significant importance. We carry out experiments and measure the fluctuation signals from a rotating electric field conductance sensor with eight electrodes. We use recurrence plot and adaptive optimal kernel time–frequency representation to recognize different oil–water–gas three-phase flow patterns from experimental measurements. Then we employ multi-scale weighted complexity entropy causality plane (MS-WCECP) to explore the nonlinear characteristics for five typical oil–water–gas three-phase flow structures. The results suggest that our method enables to indicate flow pattern transitions. In particular, with the increase of scales, more information will be lost. Slug flow ends up in chaotic region, representing high complexity; Churn flow falls down from the chaotic to the random noise area, indicating the decreasing stability; while the drop degree of bubble flow is the biggest, suggesting that bubble flow has the most randomness. These findings demonstrate that multi-scale weighted complexity entropy causality plane can effectively depict the transitions of three-phase flow structures and serve as a useful tool for probing the nonlinear dynamics of the three-phase flows.

Multi-Scale Long-Range Magnitude and Sign Correlations in Vertical Upward Oil–Gas–Water Three-Phase Flow

Abstract In this article we apply an approach to identify the oil–gas–water three-phase flow patterns in vertical upwards 20 mm inner-diameter pipe based on the conductance fluctuating signals. We use the approach to analyse the signals with long-range correlations by decomposing the signal increment series into magnitude and sign series and extracting their scaling properties. We find that the magnitude series relates to nonlinear properties of the original time series, whereas the sign series relates to the linear properties. The research shows that the oil–gas–water three-phase flows (slug flow, churn flow, bubble flow) can be classified by a combination of scaling exponents of magnitude and sign series. This study provides a new way of characterising linear and nonlinear properties embedded in oil–gas–water three-phase flows.

Gas–liquid–liquid three-phase flow pattern and pressure drop in a microfluidic chip: similarities with gas–liquid/liquid–liquid flows

We report a three-phase slug flow and a parallel-slug flow as two major flow patterns found under the nitrogen-decane-water flow through a glass microfluidic chip which features a long microchannel with a hydraulic diameter of 98 μm connected to a cross-flow mixer. The three-phase slug flow pattern is characterized by a flow of decane droplets containing single elongated nitrogen bubbles, which are separated by water slugs. This flow pattern was observed at a superficial velocity of decane (in the range of about 0.6 to 10 mm s(-1)) typically lower than that of water for a given superficial gas velocity in the range of 30 to 91 mm s(-1). The parallel-slug flow pattern is characterized by a continuous water flow in one part of the channel cross section and a parallel flow of decane with dispersed nitrogen bubbles in the adjacent part of the channel cross section, which was observed at a superficial velocity of decane (in the range of about 2.5 to 40 mm s(-1)) typically higher than that of water for each given superficial gas velocity. The three-phase slug flow can be seen as a superimposition of both decane-water and nitrogen-decane slug flows observed in the chip when the flow of the third phase (viz. nitrogen or water, respectively) was set at zero. The parallel-slug flow can be seen as a superimposition of the decane-water parallel flow and the nitrogen-decane slug flow observed in the chip under the corresponding two-phase flow conditions. In case of small capillary numbers (Ca ≪ 0.1) and Weber numbers (We ≪ 1), the developed two-phase pressure drop model under a slug flow has been extended to obtain a three-phase slug flow model in which the 'nitrogen-in-decane' droplet is assumed as a pseudo-homogeneous droplet with an effective viscosity. The parallel flow and slug flow pressure drop models have been combined to obtain a parallel-slug flow model. The obtained models describe the experimental pressure drop with standard deviations of 8% and 12% for the three-phase slug flow and parallel-slug flow, respectively. An example is given to illustrate the model uses in designing bifurcated microchannels that split the three-phase slug flow for high-throughput processing.

VISIBILITY GRAPHS FROM EXPERIMENTAL THREE-PHASE FLOW FOR CHARACTERIZING DYNAMIC FLOW BEHAVIOR

We systematically carried out oil–gas–water three-phase flow experiments for measuring the time series of flow signals. We first investigate flow pattern behaviors from the energy and frequency point of view and find that different flow patterns exhibit different flow behaviors. In order to quantitatively characterize dynamic behaviors underlying different oil–gas–water three-phase flow patterns, we infer and analyze visibility graphs (complex networks) from signals measured under different flow conditions. The results indicate that the combination parameters of network degree are sensitive to the transition among different flow patterns, which can be used to distinguish different flow patterns and quantitatively characterize nonlinear dynamics of the three-phase flow. In this regard, visibility graph can be a useful tool for characterizing the nonlinear dynamic behaviors underlying different oil–gas–water three-phase flow patterns.

Nonlinear dynamical analysis of large diameter vertical upward oil–gas–water three-phase flow pattern characteristics

Based on two kinds of signals measured from mini-conductance probe array and vertical multi-electrode array (VMEA) conductance sensor, we study oil–gas–water three-phase flow in a vertical upward 125 mm ID pipe. Using the ratio of oil flowrate to total liquid flowrate ( f o ) and the superficial gas velocity ( U sg ), we draw the six different flow pattern maps under four total mixture liquid flowrates. In addition, we indicate that: (a) the increase of f o makes oil in water type slug flow occur at lower U sg ; (b) for large diameter pipe and low flow velocity, the phase inversion of liquids occurs at about f o =0.9 and the increase of U sg makes the phase inversion of liquids move to low f o . Furthermore, we investigate the nonlinear dynamical characteristics of five water continuous phase flow patterns in terms of chaotic attractor morphological description and complexity measures (Lempel–Ziv complexity and approximate entropy), and find that: (a) the chaotic attractor morphological characteristics can identify three-phase flow patterns; (b) the combination of Lempel–Ziv complexity and approximate entropy can serve as a unique classification criterion of three-phase flow patterns. In this regard, the nonlinear analysis of conductance fluctuating signals can give an effective indicator to understand and identify the oil–gas–water three-phase flow pattern characteristics.