A Novel Approach to Subsea Multiphase Solid Transport

2011 ◽  
Vol 367 ◽  
pp. 413-420
Author(s):  
Kelani Bello ◽  
Babs Mufutau Oyeneyin ◽  
Gbenga Folorunso Oluyemi
Keyword(s):  
Multiphase Flow ◽  
Flow Patterns ◽  
Sand Transport ◽  
Operational Parameters ◽  
Flow Loop ◽  
Transport Models ◽  
Horizontal Pipe ◽  
Main Challenge ◽  
Three Phase ◽  
Solid Transport

Transportation of multiphase reservoir fluid through subsea tiebacks has gained considerable attention in recent years especially in the deep offshore and ultra deep offshore environments where there is increasing pressure on the operators to reduce development costs without compromising oil production. However, the main challenge associated with this means of transporting unprocessed reservoir fluids is the need to guarantee flow assurance and optimise production. Solids entrained in the fluid may drop off and settle at the bottom of horizontal pipe thereby reducing the space available to flow and causing erosion and corrosion of the pipeline. The problem has been largely attributed to insufficient flow velocity among other parameters required to keep the solids in suspension and prevent them from depositing in the pipe. The continuous changing flow patterns have introduced additional complexities dependent on gas and liquid flow rates. Acquisition of experimental data for model development and validation in multiphase flow has been largely focused on single and two phase flow. This has impeded our understanding of the behaviour and associated problems of three phase or four phase (oil, water, gas and solid) in pipes. The result is inappropriate solid transport models for three phase and four phase. In order to bridge this gap, the Well Engineering Research group at Robert Gordon University has initiated a project on integrated multiphase flow management system underpinned by comprehensive experimental investigation of multiphase solids transport. The project is aimed at developing precise/accurate sand transport models and an appropriate design and process optimisation simulator for subsea tiebacks. In this paper, the physics of the multiphase transport models being developed is presented. The models will allow for the prediction of key design and operational parameters such as flow patterns, phase velocity, pressure gradient, critical transport velocity, drag & lift forces, flow rate requirements and tiebacks sizing for transient multiphase flow. A new multiphase flow loop is being developed which will be used to generate experimental database for building and validating the theoretical models for use in a proposed integrated simulator for deepwater applications.

Sand Erosion in Multiphase Flow for Low-Liquid Loading and Annular Conditions

2012 ◽  
Author(s):  
R. E. Vieira ◽  
N. R. Kesana ◽  
B. S. McLaury ◽  
S. A. Shirazi
Keyword(s):  
Multiphase Flow ◽  
Multiphase Flows ◽  
Large Scale ◽  
Flow Patterns ◽  
Production Equipment ◽  
Flow Loop ◽  
Liquid Loading ◽  
Vertical Orientation ◽  
Horizontal Orientation ◽  
Sand Erosion

Low-liquid loading (LLL) and annular gas-liquid flow patterns are commonly encountered in gas transportation pipelines. They may also occur in other off-shore production facilities such as gas/condensate production systems. Experience gained from production of hydrocarbons has shown that severe degradation of production equipment will occur due to sand entrained in gas-dominant multiphase flows. Sand erosion in multiphase flows is a complex phenomenon since several factors influence the particle impact velocity with the wall. In order to give a more comprehensive understanding of the particle erosion process in this particular scenario and to improve the current semi-mechanistic models, erosion and sand distribution measurements were conducted on 76.2 mm (3 inch) and 101.6 mm (4 inch) diameter pipes in a large scale multiphase flow loop with varying gas (air) and liquid (water) velocities generating low-liquid loading and annular conditions. Particle sizes used in the experiments were 150 and 300 microns with the latter being sharper than the former. Erosion measurements were made at sixteen different locations on a 76.2 mm (3 inch) standard elbow using ultrasonic technology, whereas Electrical Resistance (ER) probes were used for the measurements in a 101.6 mm (4 inch) diameter pipe. The experiments were primarily performed in the upward vertical orientation but a few measurements were performed in the horizontal orientation. Results suggest that the erosion is an order of magnitude higher when the pipe is oriented vertically compared to horizontal orientation. Also, the location of maximum erosion is identified for these flow patterns and it is not dependent on the pipe inclination.

scholarly journals Experimental Study on the Flow Regimes and Pressure Gradients of Air-Oil-Water Three-Phase Flow in Horizontal Pipes

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Luai M. Al-Hadhrami ◽  
S. M. Shaahid ◽  
Lukman O. Tunde ◽  
A. Al-Sarkhi
Keyword(s):  
Tap Water ◽  
Strong Dependence ◽  
Flow Regimes ◽  
Flow Patterns ◽  
Pressure Gradients ◽  
Horizontal Pipe ◽  
Three Phase ◽  
Wide Range ◽  
Oil Water ◽  
Water Cut

An experimental investigation has been carried out to study the flow regimes and pressure gradients of air-oil-water three-phase flows in 2.25 ID horizontal pipe at different flow conditions. The effects of water cuts, liquid and gas velocities on flow patterns and pressure gradients have been studied. The experiments have been conducted at 20°C using low viscosity Safrasol D80 oil, tap water and air. Superficial water and oil velocities were varied from 0.3 m/s to 3 m/s and air velocity varied from 0.29 m/s to 52.5 m/s to cover wide range of flow patterns. The experiments were performed for 10% to 90% water cuts. The flow patterns were observed and recorded using high speed video camera while the pressure drops were measured using pressure transducers and U-tube manometers. The flow patterns show strong dependence on water fraction, gas velocities, and liquid velocities. The observed flow patterns are stratified (smooth and wavy), elongated bubble, slug, dispersed bubble, and annular flow patterns. The pressure gradients have been found to increase with the increase in gas flow rates. Also, for a given superficial gas velocity, the pressure gradients increased with the increase in the superficial liquid velocity. The pressure gradient first increases and then decreases with increasing water cut. In general, phase inversion was observed with increase in the water cut. The experimental results have been compared with the existing unified Model and a good agreement has been noticed.

scholarly journals Downward Annular Flow of Air–Oil–Water Mixture in a Vertical Pipe

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 30
Author(s):  
Agata Brandt ◽  
Krystian Czernek ◽  
Małgorzata Płaczek ◽  
Stanisław Witczak
Keyword(s):  
Multiphase Flow ◽  
Void Fraction ◽  
Flow Patterns ◽  
Phase Flow ◽  
Water Mixture ◽  
Vertical Pipe ◽  
Two Phase ◽  
Liquid Concentration ◽  
Three Phase ◽  
Oil Water

The paper presents the results of a study concerned with the hydrodynamics of an annular downward multiphase flow of gas and two mutually non-mixing liquids through a vertical pipe with a diameter of 12.5 mm. The air, oil and water were used as working media in this study with changes in superficial velocities in the ranges of jg = 0.34–52.5 m/s for air, jo = 0.000165–0.75 m/s for oil, and jw = 0.02–2.5 m/s for water, respectively. The oil density and viscosity were varied within the ranges of ρo = 859–881 kg/m3 and ηo = 29–2190 mPas, respectively. The research involved the identification of multiphase flow patterns and determination of the void fraction of the individual phases. New flow patterns have been identified and described for the gravitational flow conditions of a two-phase water–oil liquid and a three-phase air–water–oil flow. New flow regime maps and equations for the calculation of air, oil and water void fractions have been developed. A good conformity between the calculated and measured values of void fraction were obtained. The map for the oil–water–air three-phase flow is valid for the following conditions: j3P = 0.35–53.4 m/s (velocity of three-phase mixture) and oil in liquid concentration βo* = 0.48–94% (oil in liquid concentration). In the case of a downward annular oil–water two-phase flow, this map is valid for liquid mixture velocity jl = 0.052–2.14 m/s and βo* = 0.48–94%.

Influence of Gas-Liquid Two-Phase Intermittent Flow on Hydraulic Sand Dune Migration in Horizontal Pipelines

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Afshin Goharzadeh ◽  
Peter Rodgers ◽  
Chokri Touati
Keyword(s):  
High Speed ◽  
Sand Dune ◽  
Front Velocity ◽  
Intermittent Flow ◽  
Sand Particle ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Particle Mobility ◽  
Three Phase ◽  
Gas Ratio

This paper presents an experimental study of three-phase flows (air-water-sand) inside a horizontal pipe. The results obtained aim to enhance the fundamental understanding of sand transportation due to saltation in the presence of a gas-liquid two-phase intermittent flow. Sand dune pitch, length, height, and front velocity were measured using high-speed video photography. Four flow compositions with differing gas ratios, including hydraulic conveying, were assessed for sand transportation, having the same mixture velocity. For the test conditions under analysis, it was found that the gas ratio did not affect the average dune front velocity. However, for intermittent flows, the sand bed was transported further downstream relative to hydraulic conveying. It was also observed that the slug body significantly influences sand particle mobility. The physical mechanism of sand transportation was found to be discontinuous with intermittent flows. The sand dune local velocity (within the slug body) was measured to be three times higher than the averaged dune velocities, due to turbulent enhancement within the slug body.

Particle Transport Coefficient (PTC) and Phase-Efficiency Diagram: A New Perspective to Evaluate Three-Phase Particle-Laden Flow

2020 ◽  
Author(s):  
Zhifeng Zhang ◽  
Antoine Jean-Claude Jacques Pruvot ◽  
Pablo Cisternas ◽  
James McAndrew
Keyword(s):  
Particle Transport ◽  
Transport Coefficient ◽  
Vertical Direction ◽  
Environmental Cost ◽  
Mathematical Form ◽  
Horizontal Pipe ◽  
Carrier Fluid ◽  
Transport Efficiency ◽  
Three Phase ◽  
New Perspective

Abstract Many technologies have been developed to improve the ability of fluids to transport particles. However, the evaluation of particle transport efficiency remains challenging, especially in complex flow such as three-phase flow. In the present research, theoretical and experimental work is conducted to develop a new perspective of evaluating particle transport technologies, particle transport coefficient (PTC) as the particle transport distance per unit volume of water consumption considering the transport efficiency and environmental cost. The mathematical form of the PTC for the steady-state transport case is derived, followed by three special transport cases: (a) PTC = 0 when particle settled or stuck, (b) PTC = infinity in the vertical direction, considering gravity or buoyant with carrier fluid stationary, while PTC = 0 in a horizontal pipe due to particle settlement; and (c) PTC = 2 for an infinitely small particle at the center of a fully-developed laminar flow in a pipe. Furthermore, the fluid property and surface property influence on PTC are experimentally demonstrated. We believe the proposed approach can promote the development of particle transport technologies.

Multiphase Flow in Circular and Triangular Pipes: Examining Flow Characteristics, Sand Erosion and Heat Transfer Via CFD and Experimental Work

2021 ◽  
Author(s):  
Ronald E. Vieira ◽  
Thiana A. Sedrez ◽  
Siamack A. Shirazi ◽  
Gabriel Silva
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Experimental Work ◽  
Heat Exchangers ◽  
Flow Patterns ◽  
Cfd Simulations ◽  
Liquid Distribution ◽  
Circular Pipes ◽  
Sand Erosion ◽  
Sand Flow

Abstract Air-water two-phase flow in circular pipes has been studied by many investigators. However, investigations of multiphase flow in non-circular pipes are still very rare. Triangular pipes have found a number of applications, such as multiphase flow conditioning, erosion mitigation in elbows, compact heat exchanges, solar heat collectors, and electronic cooling systems. This work presents a survey of air-water and air-water-sand flow through circular and triangular pipes. The main objective of this investigation is to study the potential effects of triangular pipe geometry on flow patterns, slug frequency, sand erosion in elbows, and heat transfer in multiphase flow. Firstly, twenty-three experiments were performed for horizontal air-water flow. Detailed videos and slug frequency measurements were collected through circular and triangular clear pipes to identify flow patterns and create a database for these pipe configurations. The effect of corners of the triangular pipe on the liquid distribution was investigated using two different orientations of triangular pipe: apex upward and downward and results of triangular pipes were compared to round tubes. Secondly, ultrasonic wall thickness erosion measurements, paint removal studies, and CFD simulations were carried out to investigate the erosion patterns and magnitudes for liquid-sand and liquid-gas-sand flows in circular and triangular elbows with the same radius of curvature and cross-sectional area. Thirdly, heat transfer rates for liquid flows were also simulated for both circular and triangular pipe cross-sections. Although similar flow patterns are observed in circular and triangular pipe configurations, the orientation of the triangular pipes seems to have an effect on the liquid distribution and slug frequency. For higher liquid rates, slug frequencies are consistently lower in the triangular pipe as compared to the circular pipe. Similarly, the triangular elbow offers better flow behavior as compared to circular elbows when investigated numerically with similar flow rates for erosion patterns for both liquid-sand flow and liquid-gas-sand flows. Experimental and CFD results show that erosion in the circular elbow is about three times larger than in the triangular elbow. Paint studies results validated erosion patterns and their relations with particle impacts. Finally, heat transfer to/from triangular pipes is shown to be more efficient than in circular pipes, making them attractive for compact heat exchangers and heat collectors. This paper represents a novel experimental work and CFD simulations to examine the effects of pipe geometries on multiphase flow in pipes with several practical applications. The present results will help to determine the efficiency of utilizing triangular pipes as compared to circular pipes for several important applications and field operations such as reducing slug frequencies of multiphase flow in pipes, and reducing solid particle erosion of elbows, and also increasing the efficiency of heat exchangers.

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