Erosion and Corrosion for Oil & Gas Equipment - DNV GL Parsi_Erosion and... · Erosion and...

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Mazdak Parsi

OIL & GAS

Erosion and Corrosion for Oil & Gas Equipment

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(Application of CFD)

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Outline

Erosion in Oil and Gas Equipment

Erosion Equation Development

Erosion in Choke valves

CFD-based Erosion Modeling for Multiphase Flow

RCA Multiphase Flow Modeling

Conclusions

2

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Erosion in Oil and Gas Equipment

“For the majority of oil & gas fields, sand

from the reservoir formation is an

inevitable by-product”.

Erosion: a complex mechanical process in

which material is removed from the

pipeline due to repeated sand particle

impacts.

“Sand may cause damage to well

components such as sand screens,

tubing, down-hole safety valves,

electrical submersed pumps (ESPs)”.

Consequences: pipe failures, financial

losses, environmental issues…

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Examples of Erosion

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CFD-Based Erosion Modeling

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Figure 3: CFD unstructured mesh with 770k elements and inflation layers around the specimen.

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(a) 30º (b) 45º (c) 60º (d) 75º

(e) 90º (f) flow streamlines for θ = 90º

Figure 6: Contours of velocity magnitude for different impact angles (Vg = 102 m/s).

Velocity Contours

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(a)

(b)

(c)

Figure 11: Erosion ratios for gas velocities of a) 54 m/s, b) 79 m/s, c) 102 m/s.

(a)

(b)

(c)

Figure 11: Erosion ratios for gas velocities of a) 54 m/s, b) 79 m/s, c) 102 m/s.

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Examples – Erosion in Choke Valves

Problem: Particle impact at the small

area with high velocity causing

excessive erosion

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Flow Inlet

Particle trajectories colored by velocity and associated erosion

area for two chokes

Area of high erosion

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Examples – Erosion in Choke Valves (Cont’d)

Results

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Brick stopper

Choke gallery Downstream piping

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CFD-Based Erosion Modeling for Multiphase Flow

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Early Life Late Life

Gas condensate wells

liquid production increases

pressure decreases

gas flow rate decreases

Annular flow Slug flow Churn flow transition

Introduction and Background

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Wire-Mesh Sensor (Validation of CFD Results)

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CFD simulations require experimental data for validation.

Wire-Mesh Sensor provides void fraction distribution over the pipe cross-

section.

Data Analysis: phase distributions, void fraction time series, periodic structure

velocities, etc.

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Phase Distributions (different liquid structures)

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Void Fraction

Liquid

Gas

Slug Pseudo Slug Huge Wave

Violent Agitation

Gas Trough

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CFD Simulation of Multiphase Flow

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gas liquid

Typical Mesh

Typical Inlet Conditions

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CFD vs WMS Data (Void Fraction Time Series)

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CFD vs WMS (Radial Void Fraction Profile)

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VSG = 10.3 m/s VSL= 0.30 m/s

VSG = 18.1 m/s VSL= 0.30 m/s

VSG = 27.3 m/s VSL= 0.30 m/s

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• Unsteady flow simulation and particle tracking are simultaneously

performed.

• The value of mass removal of wall per unit area was recorded during the simulation run-time. When the rate of mass removal reached a steady-state condition, the rate was used for erosion computation.

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VSG = 10.3 m/s VSL= 0.30 m/s

Steady-state

Particles start to impact


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VSG = 27.3 m/s VSL= 0.30 m/s


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Comparison of CFD Erosion Results to Experimental Data

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VSG

(m/s)

VSL

(m/s)

Particle Size

(micron)

Erosion

Rate (mpy)

VSG

(m/s)

VSL

(m/s)

Particle Size

(micron)

Erosion

Rate (mpy)

1 9.8 0.58 300 587 10.3 0.3 300 1258

2 17.7 0.36 300 3154 18.1 0.3 300 3145

3 27.2 0.32 300 7421 27.3 0.3 300 7863

4 27.2 0.32 150 3681 27.3 0.3 150 3128

Case

No.

Experiment CFD

Experimental UT Data Acquisition

CFD vs Experiments (Parsi et al.; 2015)

Experiments: ultrasonic technique was

employed to measure erosion rates for a

variety of flow conditions.

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Erosion in Horizontal Multiphase Flow

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Passage of a pseudo slug (flow direction from left to right)

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Void Fraction Time Series

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X= 1m

X= 5m

X= 9m

Distance from inlet

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Iso-void Fraction

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Erosion in Horizontal Multiphase Flow

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Liquid film covering a large region of the elbow (flow direction from left to right).

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time-step air-water phase distributions particle concetration

t = 39.0 s

t = 40.0 s

t = 44.0 s

t = 46.0 s

t = 50.5 s

t = 52.0 s

Figure 10: Phase distribution and particle concentration contours at different time-step.

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RCA Multiphase Flow Modeling

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Figure 1. Model of RC and computational grid.

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Acknowledgement

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• Dr. Mustafa Kara (DNV GL) • Dr. Jose Vera (DNV GL) • Mr. Madhu Agrawal (BP) • Dr. Anchal Jatale (ANSYS)

Erosion and Corrosion for Oil & Gas Equipment - DNV GL Parsi_Erosion and... · Erosion and...

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