Flow-Induced Vibrations of Subsea Jumpers due to Internal Multi-Phase Flow

2011 ◽  
Author(s):  
Juan P. Pontaza ◽  
Raghu G. Menon
Keyword(s):  
Structural Response ◽  
Phase Flow ◽  
Flow Conditions ◽  
Flow Induced Vibration ◽  
Flow Induced Vibrations ◽  
Weld Fatigue ◽  
Multi Phase Flow ◽  
Temperature And Pressure ◽  
Multi Phase ◽  
Dominant Frequencies

Subsea jumpers are steel pipe sections that connect hardware components on the seafloor (e.g. trees, manifolds, and sleds) and typically operate in multi-phase flow. They are designed with bends to accommodate limited expansion due to variations in temperature and pressure. Under certain conditions significant fluctuating forces can be induced in flow-turning elements like bends and tees. These fluctuating forces may cause severe piping vibrations and weld fatigue damage. This paper presents a flow-induced vibration screening procedure based on the 3-D numerical simulation of unsteady internal multi-phase flow in subsea well jumpers, the prediction of associated flow-induced forces in flow-turning elements, and the prediction of structural response, including fatigue life estimates. We consider a 6 inch (nominal) diameter well jumper with six turning elements (i.e. six blind Tees), having 70 feet of suspended span, and perform simulations for two different flow conditions representative of early- and mid-life production. We find that the dominant frequencies of flow-induced vibration are those associated with modes 1 through 4 and that stresses are highest in mid-life flow conditions when the gas volumetric void fraction is 55%.

Four-Phase Flow of Oil, Gas, Water, and Sand Mixtures in Subsea Pipelines

2020 ◽  
Author(s):  
Mohamed Odan ◽  
Faraj Ben Rajeb ◽  
Mohammad Azizur Rahman ◽  
Amer Aborig ◽  
Syed Imtiaz ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Fluid Velocity ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Multi Phase Flow ◽  
Flow Variables ◽  
Multi Phase ◽  
Subsea Pipelines ◽  
The Impact ◽  
Oil Gas

Abstract This paper investigates issues around four-phase (Oil/CO2/water/sand) flows occurring within subsea pipelines. Multi-phase flows are the norm, as production fluid from reservoirs typically include sand with water. However, these multi-phase flow mixtures, whether three- or four-phase, are at risk of forming slug flows. The inclusion of sand in this mixture is concerning, as it not only leads to increased levels of pipeline erosion but it also has the potential, to accumulate sand at the bottom of the pipe, blocking the pipe or at the very least hindering the flow. This latter impact can prove problematic, as a minimum fluid velocity must be maintained to ensure the safe and regulated flow of particles along a pipeline. The presence of low amounts of sand particles in oil/gas/water flow mixtures can serve to reduce the pressure exerted on bends. The sand volume fraction must in this case, be relatively low such that the particles’ resistance causes only a moderate loss in pressure. Therefore, the study aims to gauge the impact of oil/gas/water/sand mixtures on various pipeline structures as well as to further investigate the phenomenon of flow-induced vibration to determine the optimal flow variables which can be applied predicting the structural responses of subsea pipelines.

Towards Understanding Two-Phase Flow Induced Vibration of Piping Structure With a U-Bend

2019 ◽  
Author(s):  
Olufemi E. Bamidele ◽  
Wael H. Ahmed ◽  
Marwan Hassan
Keyword(s):  
Void Fraction ◽  
Vibration Amplitude ◽  
Two Phase Flow ◽  
Bubbly Flow ◽  
Phase Flow ◽  
Flow Conditions ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Void Fractions ◽  
Flow Induced Vibrations

Abstract The current work investigates two-phase flow induced vibrations in 90° U-bend. The two-phase induced vibration of the structure was investigated in the vertical, horizontal and axial directions for various flow patterns from bubbly flow to wavy and annular-dispersed flow. The void fractions at various locations along the piping including the fully developed void fraction and the void fraction at the entrance of the U-bend were fully investigated and correlated with the vibration amplitude. The results show that the excitation forces of the two-phase flow in a piping structure are highly dependent on the flow pattern and the flow conditions upstream of the bend. The fully developed void fraction and slip between phases are important in modelling of forces in U-bends and elbows.

A Fourier Collocation Approach for Transit-Time Ultrasonic Flowmeter Under Multi-Phase Flow Conditions

2017 ◽  
Vol 25 (04) ◽  
pp. 1750005 ◽  
Author(s):  
Matej Simurda ◽  
Benny Lassen ◽  
Lars Duggen ◽  
Nils T. Basse
Keyword(s):  
Transit Time ◽  
Ultrasonic Flowmeter ◽  
Flow Profile ◽  
Phase Flow ◽  
Flow Conditions ◽  
Perfectly Matched Layers ◽  
Acoustic Media ◽  
Multi Phase Flow ◽  
Multi Phase ◽  
Fourier Collocation

A numerical model for a clamp-on transit-time ultrasonic flowmeter (TTUF) under multi-phase flow conditions is presented. The method solves equations of linear elasticity for isotropic heterogeneous materials with background flow where acoustic media are modeled by setting shear modulus to zero. Spatial derivatives are calculated by a Fourier collocation method allowing the use of the fast Fourier transform (FFT) and time derivatives are approximated by a finite difference (FD) scheme. This approach is sometimes referred to as a pseudospectral time-domain method. Perfectly matched layers (PML) are used to avoid wave-wrapping and staggered grids are implemented to improve stability and efficiency. The method is verified against exact analytical solutions and the effect of the time-staggering and associated lowest number of points per minimum wavelengths value is discussed. The method is then employed to model a complete TTUF measurement setup to simulate the effect of a flow profile on the flowmeter accuracy and a study of an impact of inclusions in flowing media on received signals is carried out.

Assessment of Computational Fluid Dynamics for Predicting Possible Cavitation and Choked Flow Inside Excess Flow Valves

2020 ◽  
Author(s):  
Nafiseh Banazadeh-Neishabouri ◽  
Siamack A. Shirazi ◽  
Jud Smalley ◽  
Mike Lybarger
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Critical Conditions ◽  
Vapor Flow ◽  
Phase Flow ◽  
Flow Conditions ◽  
Choked Flow ◽  
Multi Phase Flow ◽  
Multi Phase

Abstract Cavitation and choked flow conditions can occur when high-pressure drops are encounters in various types of valves, which prevent them to work properly and may cause severe erosion damage inside the valves that decrease their lifetime. Prediction of these critical conditions leads to the prevention of cavitation and helps to improve the design of the valve geometries to delay and prevent these critical flow conditions. Computational Fluid Dynamics (CFD) is a powerful tool that can be used to simulate flow conditions and to predict the incipient of cavitation and consequently choked flow in the valve through solving the Time Averaged Navier-Stokes equations under multi-phase flow conditions. Therefore, CFD simulations have been conducted for two types of excess flow valves. The mixture multi-phase flow solution method along with the k-ε realizable turbulence model has been utilized to solve the behavior of vapor flow inside the valve and simulate the cavitation phenomenon. It was observed that CFD could capture the inception of cavitation and choked flow inside the valve successfully. Simulated CFD results also indicated a good agreement with experimental data that were obtained under lower pressure drop conditions. The effects of various inlet pressures on the cavitation intensity have been also studied, and it was concluded that at higher inlet pressure with constant pressure outlet the cavitation strength is greater than lower inlet pressures.

Four-Phase Flow of Oil, Gas, Water, and Sand Mixtures in Pipelines

2020 ◽  
Author(s):  
Mohamed Odan ◽  
Faraj Ben Rajeb ◽  
Mohammad Azizur Rahman ◽  
Amer Aborig ◽  
Syed Imtiaz ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Fluid Velocity ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Structural Responses ◽  
Multi Phase Flow ◽  
Flow Variables ◽  
Multi Phase ◽  
The Impact ◽  
Oil Gas

Abstract This paper investigates issues around four-phase (Oil/CO2/water/sand) flows occurring within pipelines. Multiphase flows are the norm, as production fluid from reservoirs typically include sand with water. However, these multi-phase flow mixtures, whether three- or four-phase, are at risk of forming slug flows. The inclusion of sand in this mixture is concerning, as it not only leads to increased levels of pipeline erosion but it also has the potential, to accumulate sand at the bottom of the pipe, blocking the pipe or at the very least hindering the flow. This latter impact can prove problematic, as a minimum fluid velocity must be maintained to ensure the safe and regulated flow of particles along a pipeline. The presence of low amounts of sand particles in oil/gas/water flow mixtures can serve to reduce the pressure exerted on bends. The sand volume fraction must in this case, be relatively low such that the particles’ resistance causes only a moderate loss in pressure. Therefore, the study aims to gauge the impact of oil/gas/water/sand mixtures on various pipeline structures as well as to further investigate the phenomenon of flow-induced vibration to determine the optimal flow variables which can be applied predicting the structural responses of pipelines.

Evaluation of the impact of multi-phase flow on reservoir signatures in the Wolfcamp shale

2020 ◽  
Vol 76 ◽  
pp. 103187
Author(s):  
C.R. Clarkson ◽  
B. Yuan ◽  
Z. Zhang ◽  
F. Tabasinejad ◽  
H. Behmanesh ◽  
...  
Keyword(s):  
Phase Flow ◽  
Multi Phase Flow ◽  
Multi Phase ◽  
The Impact
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