New Algorithm to Discriminate Phase Distribution of Gas-Oil-Water Pipe Flow With Dual-Modality Wire-Mesh Sensor

Three-phase gas-oil-water flow is an important type of flow present in petroleum extraction and processing. This paper reports a novel threshold-based method to visualize and estimate the cross-sectional phase fraction of gas-oil-water mixtures. A 16×16 dual-modality wire-mesh sensor (WMS) was employed to simultaneously determine the conductive and capacitive components of the impedance of fluid. Then, both electrical parameters are used to classify readings of WMS into either pure substance (gas, oil or water) or two-phase oil-water mixtures (foam is neglected in this work). Since the wire-mesh sensor interrogates small regions of the flow domain, we assume that the three-phase mixture can be segmented according to the spatial sensor resolution (typically 2–3 mm). Hence, the proposed method simplifies a complex three-phase system in several segments of single or two-phase mixtures. In addition to flow visualization, the novel approach can also be applied to estimate quantitative volume fractions of flowing gas-oil-water mixtures. The proposed method was tested in a horizontal air-oil-water flow loop in different flow conditions. Experimental results suggest that the threshold-based method is able to capture transient three-phase flows with high temporal and spatial resolution even in the presence of water-oil dispersion regardless of the continuous phase

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

Experimental and Numerical Development of a Two-Phase Venturi Flow Meter

An algebraic model is developed access the gas and the liquid flow rates of a tw

Bridging the Gap in Hydrates and Multiphase Flow

Poster session : Flow AssuranceInternational audienceGas hydrates is a significant part in the portfolio of topics covered in the flow assurance of oil and gas production. Major advances have been made in understanding hydrates formation in multiphase system, which has enabled a gradual shift in practice to hydrate management from avoidance. In hydrate management, the challenges for hydrates also shift from formation to transportability, which is significantly a much more complex problem due to the hydrodynamic of flow and dispersion of the phases. As such, understanding the interplay of hydrates and multiphase flow is critically important, especially in quan tifying how hydrate formation is determined by the flow characteristics and how the flow regime is altered by the presence and distribution of hydrates. This contribution explores the limited knowledge in this area and expands on the experimental and modeling areas which must be studied to develop the knowledge and tools for effective hydrate management. Some of the key areas to be discussed include hydrate distribution in flowlines and among phases, hydrate deposition, hydrate non-equilibrium kinetics, hydrate accumulation, flow regime, and phases dispersion

Modeling Gas Hydrate Growth Kinetics in Water-in-Oil Emulsion for Offshore Petroleum Production Applications

Carlos Lange Bassani a remporté le prix du meilleur poster lors de la journée scientifique du CODEGEPRA 2017International audienceThe high pressure and low temperature conditions commonly found in offshore oil & gas production scenarios favor the formation of gas hydrates, which may block the production pipeline causing several revenue losses. Gas hydrates are crystals formed by the imprisonment of gas molecules (e.g., lighthydrocarbons) in a cage of hydrogen-bonded water molecules. The multiphase flow inside the pipelines (composed by oil, gas, sand and water with salt) determines the interfacial surfaces between the phases (e.g., oil & gas, oil & water), which by their turn are essential to predict the order ofmagnitude of each competing phenomena on the hydrate growth kinetics. The present study couples gas absorption by the bulk, gas diffusion and water permeability through the hydrate shell with the phenomena of particle core pressurization and crystal integration processes either in the inner and outer particle surface for predicting gas hydrate growth in water-in-oil emulsions. The model results in three ODE’s for the inner and outer growth radius and for the bulk gas concentration. The initial size of the hydrate particles come from the radius of the water droplets, estimated via the turbulence vs. surface energy criterion of Hinze. Preliminary implementations show that the model captures the mass transfer limitation due to the hydrate shell growth, which is represented by the asymptotic trend of the amount of gas consumed over time. Future work shall be done in order to couple the present model with pressure and temperature predictions over the production pipeline (from multiphase flow calculations), to measure the necessary closure parameters of the model (e.g., constant of proportionality of the crystal integration process, gas diffusion and absorption coefficients, etc.) and to validate the model against experimental data

Numerical simulation of gas-liquid flows in a centrifugal rotor

Two-phase flows generally represent an adverse condition for centrifugal pumps. Research about this topic tends to be focused on performance evaluation through experimental approaches, while numerical works are quite scarce. In this paper, the numerical investigation of the gas-liquid flow in a centrifugal rotor is carried out. An Euler-Euler, polydispersed approach is adopted, together with several gas-liquid equations to model the relevant interphase interactions. The rotor geometry is a flat radial rotor, for which previously obtained experimental data to be used as input and for validation is available. Numerical results agree well with experimental ones for a range of operating conditions. They are further explored to investigate the effect of different interphase interactions on the results. Outcomes from this work can help with the understanding of the complex mechanisms associated with gas-liquid flows in centrifugal rotors, and contribute with the progress of numerical models for its solution

Numerical investigation of the flow in a multistage electric submersible pump

This article presents a numerical study on the flow in a multistage, mixed-type Electric Submersible Pump (ESP). Several details about the application of a computational fluid dynamics (CFD) program based on the finite volume method for the numerical solution of the flow inside a multistage pump are presented. At first, the numerical model is used to evaluate the influence of turbulence models and the number of stages on performance. Next, numerical head curves for a three-stage ESP are compared with experimental data from literature for a pump of same model and number of stages, for which a good agreement is found. Then, relevant flow characteristics inside the pump stages are compared for different flow rates, such as the restriction of the net flow area at the interface between diffusers and impellers due to a reverse flow structure. Some transient flow features inside the pump are also discussed. This work can give useful insight on the application of numerical simulations of the flow in multistage, mixed-type ESPs, for which there are few works in literature. It can also contribute to expand the understanding of the flow in this type of pump, guide design optimizations and provide a basis to investigate the flow in more realistic ESP applications, such as in boosting viscous liquids and multiphase flows.The authors acknowledge the fi nancial and technical support from the TE/CENPES/PETROBRAS(Grant No. 0050.0086159.13.9

Defining a Slurry Phase Map for Gas Hydrate Management in Multiphase Flow Systems

International audienceThis study proposes a criterion for safe transportability of gas hydrate slurries in oildominant flowlines. Fluids chemistry plays a role on how the particles agglomerate, which occurs in the time window the particles take to decrease their porosity because of crystallization in the capillary walls or to seal the water within the pores by the action of chemical additives, then completely preventing any water in the outer surface of the particle and avoiding liquid bridge formation (agglomeration). Hydrodynamic aspects come from the lift vs buoyancy/weight forces that tend to suspend/settle the particles, as well as the collision and disruption rates of particles that play a role on the agglomeration process. The criterion is rather simple and shows the importance of the subcooling of crystallization, water cut, mixture velocity, and the oil-water interfacial tension that can be lowered by the use of additives. A simple chart for assuring safe, fully suspended slurry flow (low plugging risk) is proposed, called slurry phase map, and directives of its use for flowline design and management are discussed. Discussion is also given upon how to scale up laboratory measurements into field conditions by the proposal of a new dimensionless group, called Bassani number