Papers by Keyword: Multiphase Flow

Abstract: Corrosion has severe consequences for the integrity of pipelines used in the petroleum industry. Modelling and optimising the parameters of a circulating fluid are two of the numerous methods for combating corrosion. The objective of this study was to develop a multiphase flow simulation model for estimating the corrosion rate of oil and gas pipelines, considering the erosional effect. In addition to carbon dioxide (CO₂) and hydrogen sulphide (H₂S) corrosion, the present model also takes into account the impacts of chloride concentrations. The current model evaluates and reflects a comprehensive understanding of corrosion in a saline environment, making it readily applicable for estimating corrosion rates for industrial applications. The model's results indicate a prediction accuracy of about 85%. Field data gathered under a broad range of environmental conditions confirms the model's prediction accuracy. The predictions from the present model are in good agreement with the field data. In addition, the present model was found to be more effective than the model created by Dewaard and Milliam. This research is likely to have widespread applications in the oil and gas industry for predicting more accurate corrosion rates.

Abstract: The growing concern with the environment has driven the development of new technologies for the treatment of produced water. In this context, the filtering hydrocyclone appears as an interesting alternative for the treatment of these waters contaminated with oil from the petroleum industry. This research addresses the flow of fluids inside a hydrocyclone equipped with a porous wall (membrane) containing two tangential inlets and two concentric outlets, with the aim of study the impact of the formation of the polarization layer by concentration on the oily water separation process using CFD. Concentration fields and transmembrane pressure, concentration, and permeate flux profiles are presented and analyzed. The results show that the proposed filtering cyclonic separator concentrates the oil in the central region of the equipment, however, for high oil concentrations; the core expands and approaches the porous wall. Furthermore, the increase in the oil volume fraction causes a decline in the permeate flux, and an increase in feed velocity causes a decrease in the polarization layer.

Abstract: There is a significant effect for the performance of proton exchange membrane fuel cell with the liquid water generated in cathode channel during the operation process In this paper, based on the numerical simulation of three-dimensional and VOF model of multiphase flow, according to the different flow channel design and the change of different inlet temperature, the transport phenomena of multiphase flow in PEMFC is discussed at temperature effect. In U-shaped cathode channel with bump scale (h/H=1/4), a long water film is assumed to cover the surface of the gas diffusion layer at the entrance. Under the simulated oxygen flow conditions of inlet 200 Reynolds number, 4.4 Weber number and inlet temperature 333K, the water film heated is not obviously affected by oxygen flow from inlet channel to bend channel. Subsequently, the shape of water film is elongated and broken from outflow of bend channel to outlet channel. The computational results are obtained that the residual broken water film can be existed in the outlet channel. The flow field temperature can affect the residual flow rate of water film in the channel. The residual rate of water film in the hot flow field is lower than that in the cold flow field.

Abstract: Pressure drop in a vertical or deviated borehole has been found to be due to hydrostatic changes and friction as a result of the produced fluids flowing to the surface. When oil flows upwards, the flowing pressure along the tubing string drops, and this makes gas to start liberating. Thus, multiphase flow forms in the tubing string. Hence, adequate modelling of vertical lift performance is required to predict the pressure drop and subsequently the wellbore pressure because many factors are involved [1]. In this work, sensitivity analysis of multiphase flow in a well has been carried out with the aid of PROSPER in which the most accurate correlation was chosen from twelve selected built-in correlations present in the program to predict the pressure drop via gradient matching. A sensitivity analysis of the well was further performed to investigate the parameters such as tubing diameter, gas-oil ratio and wellhead pressure that were affecting the vertical lift performance of a high water cut well. The results obtained from the correlation matching showed that Dun and Ros [2] original correlation was the best fit correlation for the well. The results of the sensitivity analysis revealed that reduction of wellhead pressure from 600 psi to 400 psi could increase liquid rate by 41%. An adjustment of wellhead pressure was found to give the most significant impact on the production rate of the well as compared to other two parameters studied.

Abstract: The inlet’s geometry is always the core factor that directly affects hydrodynamics and separation efficiency of the cyclone separation types. The Gas-Liquid Cylindrical Cyclone (GLCC) separators have been developed in recent years to separate into single phases of multiphase mixtures in the oil and gas industry. It is used to substitute for the traditional separator that is used over 100 years. However, the action of phases in the instrument is very fast, complicated and unsteady which may cause the difficulty to enhance the performance of the separation phases. Besides, the effect of inlet’s structures over its hydrodynamics and performance is not fully understood. The target of this study is to use experimental modeling for two phases flow (gas-water) to evaluate the effect of inlet geometrical modifications in the reduction of liquid carry-over (LCO). Four different inlet configurations are constructed, namely: One circular inlet, two symmetric circular inlets, one square inlet and two symmetric square inlets with the gradually reduced nozzle. From the results presented in this work, we propose the use of two symmetric inlets to enhance the separator efficiency because of their effects.

Abstract: Hydrocyclones are equipment that offer various advantages and have been the subject of studying for many researches related to separation processes of gas-solid, solid-liquid, and liquid-liquid mixtures. The purpose of this work is to study the oil-water separation process in a hydrocyclone by Computational Fluid Dynamics (CFD). Results of the pressure, velocity and volume fraction fields inside the device are presented and analyzed. It was possible to conclude that the proposed mathematical model was able to predict separation performance and the three-dimensional behavior of the phases flow analyzed (water/oil) in the hydrocyclone.

Abstract: Oil-water-sand multiphase flow is widely used in oil production industry. The effect of real-time measurement of the solid phase in oil-water-sand multiphase flow parameters is significant in the monitoring of sand production. In order to improve the existing limitations in solid particle detection of a liquid-solid system, an acoustic emission signals amplify device for liquid-solid flow has been developed and its evaluation test is conducted indoor. Computational fluid dynamic (CFD) analysis method is applied based on the theory of multiphase flow macroscopic continuum. Research is conducted on the distribution of solid phase in oil-water-sand multiphase flows in impact parts. The characteristics of the acoustic emission signals of sand with different sizes and concentrations are also extracted under laboratory conditions. A primary measuring instrument based on acoustic emission is proposed and designed to amplify vibration caused by sand impact. Therefore, the acoustic emisson sensor is much easier to receive solid signal. CFD analysis results show that the impact parts amplified the solid signal caused by the acoustic emission in multiphase flows. The indoor experiment results showed that the sand particle size and concentration have a good correlation with the relative power spectrum amplitude of the signal. The device system can effectively detect sand with the content of more than 0.3 wt.‰ and with the size of fewer than 325 meshes. Accordingly, this method would be helpful to apply the acoustic emission technology in enhancing the solid detection for the multiphase system.

Abstract: Erosion is a serious problem faced in many industries that includes the transport of sand and water slurry in slurry pipe line. This paper emphasizes on the investigation of erosion on a mild steel straight pipe at different parameters including fluid velocity, particle size and concentration. The fluid velocity is selected in the range of 2.5-10 m/s using computational fluid dynamics code ANSYS-CFX. Sand particle within the size range of 100-400 µm size and concentration 5%-15% are used in this study. An Euler-Lagrange approach is used to solve the multiphase flow phenomenon. A horizontal pipe of diameter 100 mm and length 1 m (10 times of diameter) is considered for the study. The stochastic model of Sommerfeld will be used to account the wall roughness of pipe. It is also observed that the erosion wear in the pipeline strongly depends on fluid velocity, particle size and concentration.

Abstract: The growing demand for oil brings the need for discovery of deeper reservoirs, especially of ultra-deepwater reservoirs. Thus, production in marine systems using components such as risers (flexible or rigid pipes) has been the focus of many studies in different areas. These ducts are used in the transportation of multiphase fluids (oil, water and gas) produced from the oil well located on the seabed to the platform surface. Due to the extreme conditions present in the offshore fields of production, the equipments that transport produced fluids operate close to their limits. So eventually, the flexible pipes may have structural integrity faults like leaks, which can cause production losses, accidents with victims and environmental disasters. The leak depends of a number of properties or parameters measured at the site of the leak, for example, integrity of the pipe material, release of fluids and noise emission characteristics or manifestation of some other type of signal behavior, variation of pressure drops close to the leak, among others. There are a variety of techniques available for detecting leaks, among which there is the mathematical modeling approach using computational techniques. In this context, this paper aims to study the fluid dynamics of a transient multiphase flow in a catenary riser in the presence of leakage. Herein a 3D Eulerian-Eulerian model was applied, including the turbulent model (RNG k-ε), using the commercial package ANSYS CFX^® 15 to perform all simulations. The numerical results of velocity, volume fraction and pressure of the involved phases are presented and discussed.

Abstract: The onshore and offshore production of oil and natural gas is characterized by the multiphase flow in ducts and pipes, which are interconnected by various equipments such as wellhead, pumps, compressors, processing platforms, among others. The transport of oil and oil products is essential to the viability of the sector, but is susceptible to failures, that can cause great environmental damage. Considering this necessity of the transportation sector of oil and derivatives, leakage in pipelines with curved connections, are the object of study for various researchers. In this sense, this work contributes to the study of three-phase flow (oil-water-gas) in a curved pipe (90°) using Computational Fluid Dynamics. The physical domain is constituted by two tubes of 4 meters trenched by a 90° curve, with the poring whole in the curvated accessory. The mathematical model is based on a particle model, where the oil is considered as a continuous phase and the water and gas as a particulate phase. The SST (Shear Stress Transport) turbulence model was adopted. All simulations were carried out using the Ansys CFX^® 12.1 commercial code. Results of the pressure, velocity and volumetric fraction of the phases are presented and discussed.