Experimental Investigation of Three-Phase Gas-Oil-Water Slug Flow Evolution in Hilly-Terrain Pipelines (original) (raw)

Experiments in a combined up stream downstream slug flow

EPJ Web of Conferences, 2013

Slug flow induced by the combination of a downstream and an upstream two phase flow is very common in the oil industry, mainly when the pipelines are installed on hilly terrains. This phenomenon can be dangerous for the equipment operation because it induces vibrations due to the slugs intermittent movement into the separators. A loop, where it is possible to change the flow conditions and the loop geometrical parameters as the length and inclination angle of the pipe sections was built. Instruments for slug detection and for measuring their characteristic parameters as hold up, frequency, length, and velocity were installed. Three conductive probes were used for the holdup measurement in different points; all of them were designed, constructed, tested and calibrated. Experimental runs for a set of four alternated sections upstream downstream W shaped pipe have been undertaken. The gas and liquid flow rates were selected in order to obtain stratified flow at the inlet, which is the condition to induce the severe slugging. The main conclusions of the experimental results analysis are presented in this paper. The Barnea's criterion has been compared against our experimental results, three slugging regions have been found. This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2 0 , which. permits unrestricted use, distributi and reproduction in any medium, provided the original work is properly cited.

Investigation of slug flow characteristics in inclined pipelines

Computational Methods in Multiphase Flow IV, 2007

In the present work a numerical analysis of the slug flow in inclined pipelines is performed with an aim to improve the understanding of slug flow characteristics over hilly-terrain section. The solution is obtained with the two-fluid model on its one-dimensional form. It consists of two sets of conservation equations of mass and linear momentum for the liquid and gas phases. The slug capturing methodology involves the numerical solution of the equations using a finite volume formulation, which is capable of naturally predicting the onset of slugging from a stratified flow regime, as well as the growth and collapse of the slugs. Flows of an oil-gas mixture in slightly inclined pipe configurations are investigated. Three types of pipelines were considered: horizontal, descending and a V-section pipeline. The influence of the gravity effect in average slug parameters, such as frequency, velocity and length is addressed. Qualitative comparisons with experimental observations in the literature show that the methodology seems to be able to correctly predict the effect of pipe inclination on the occurrence (or not) of the slug regime, as well as different overall slugging behaviour in V-section pipes if different inlet gas and liquid superficial velocities are imposed.

Study of Slug Flow in Horizontal, Inclined, and Vertical Pipes

Environmental Science and Engineering, 2012

A way to predict two-phase liquid-gas flow patterns is presented for horizontal, vertical and inclined pipes. A set of experimental data (7702 points, distributed among 22 authors) and a set of synthetic data generated using OLGA Multiphase Toolkit v.7.3.3 (59 674 points) were gathered. A filtering process based on the experimental void fraction was proposed. Moreover, a classification of the pattern flows based on a supervised classification and a probabilistic flow pattern map is proposed based on a Bayesian approach using four pattern flows: Segregated Flow, Annular Flow, Intermittent Flow, and Bubble Flow. A new visualization technique for flow pattern maps is proposed to understand the transition zones among flow patterns and provide further information than the flow pattern map boundaries reported in the literature. Following the methodology proposed in this approach, probabilistic flow pattern maps are obtained for oil-water pipes. These maps were determined using an experimental dataset of 11 071 records distributed among 53 authors and a numerical filter with the water cut reported by OLGA Multiphase Toolkit v7.3.3.

A Study Of Normal Slug Flow In An Offshore Production Facility With a Large Diameter Flowline

SPE Production & Operations, 2009

Summary Normal (hydrodynamic) slug flow in a pipeline/riser system was studied theoretically and experimentally in this paper. Experimental data were obtained for slug flow in which the length of liquid slugs was larger than the riser height. A transient mechanistic model of this phenomenon was also developed. A good agreement between the model predictions and experimental data was achieved. Simulations of slug flow in an offshore production system with a large-diameter pipeline were performed by use of the developed model. The simulation revealed that long hydrodynamic slugs can accelerate in the riser to a velocity five times greater than the average slug velocity in the pipeline. This fact should be accounted for in the development of operating strategies for such production systems.

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

Journal of Petroleum Science and Engineering, 2017

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 GO -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 GO -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 TM 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 TM predictions of average total liquid

Experimental Investigation of Hydrodynamic Slug Flow in Pipeline-Riser Systems

2016

Activities in oil and gas industry have shifted deep offshore. There is therefore the need to envisage and accurately provide for flow assurance challenges that might be encountered throughout the life of a field. Slug flow is one of the flow assurance concerns confronting the industry. The objective of the study was to gain insight into the behaviour of hydrodynamic slug flow in pipeline-riser system. This understanding is needed for the development of appropriate slug control strategy. Experimental studi es were conducted in a 2” pipeline-riser system and a 2” horizontal two -phase flow facility. Slug envelopes were developed for the pipeline-riser system, the vertical and the horizontal pipes. The results revealed three distinct slug flow behaviours. The first type of slug was formed in the horizontal pipeline and transported through the riser pipe nearly unchanged, the second type of slugs were formed in the horizontal pipe but also experience growth in the riser pipe while the ...

Experimental investigation of slug pattern in a horizontal two-phase flow

Gas-liquid two-phase flow occurs in a wide range of engineering applications in various industrial fields. For example, without being exhaustive, in the chemical and process industry, a two-phase flow is encountered in boilers, condensers, evaporators and reactors. In the petroleum industry, a two-phase flow is observed during the production and transportation of oil and gas. Among flow patterns encountered in field operations, the slug flow appears to be dominant in horizontal and near horizontal pipelines, and is, unfortunately, the most complicated one. It is characterized by an alternate flow of liquid slugs and gas pockets, resulting in inherently unsteady hydrodynamic behavior. All the important design variables, such as gas and liquid velocity profiles, liquid holdup distribution and pressure drop vary axially and radially and exhibit fluctuations, even when the inlet liquid and gas flow rates are constant. This makes prediction of slug flow characteristics complex and challenging. This paper is therefore devoted to slug flow in horizontal pipelines and attempts to address the above-cited points. Specifically, the study aims to develop a map of flow regimes then acquire pertinent slug flow data. For that purpose, an experimental test rig was built-up to examine the process of slug initiation in a 40 mm i.d and a 14 m length horizontal pipeline. Two-phase co-current air-water pressure gradients were measured. Most of the data recorded correspond to the slug flow region, noting then rapid fluctuations in pressure. Data on slug initiation, pressure variation as well as slug frequency and length are investigated and reported hereafter.

Effects of High Oil Viscosity on Slug Liquid Holdup in Horizontal Pipes

Canadian Unconventional Resources Conference, 2011

The translational velocity, velocity of slug units, is one of the key closure relationships in two-phase flow mechanistic modeling. It is described as the summation of the maximum mixture velocity in the slug body and the drift velocity. The existing equation for the drift velocity is developed by using potential flow theory. Surface tension and viscosity are neglected. However, the drift velocity is expected to be affected with high oil viscosity. In this study, the effects of high oil viscosity on drift velocity for horizontal and upward inclined pipes are experimentally observed. The experiments are performed on a flow loop with a test section 50.8 mm ID for inclination angles of 0° to 90°. Water and viscous oil are used as test fluids. Liquid viscosities vary from 0.001 to 1.237 Pa·s.

Slug Flow in Large Diameter Pipeline-Riser Systems: Prediction and Mitigation

2018

Slug flow could pose serious threat to oil and gas production facility. The objective of the study was to gain better insight into the behaviour of slug flow in large pipe diameter pipeline-riser system. The influence of geometry configuration on the slug characteristics was also investigated. The understanding of these are very important in the development of effective slug control strategy. Numerical simulations were carried out on a 3.7 km long horizontal pipeline leading to a 0.13 km vertical riser using an industrial software package. The pipeline and riser are both of 17” internal diameter. Slug envelopes were developed for the pipeline-riser system and its constituents’ pipes. A total number of 572 data points were investigated, covering superficial velocities ranging from 0.01 to 44.28 m/s for gas and 0.02 and 8.25 m/s for liquid. The results showed three distinct slug flow regions: region due to horizontal pipeline slugging (H) where slugs formed in the horizontal pipeline ...