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NEL Slide 1 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Erosion Effects in
Flowmeters
John Peters, NEL
Tariq Boussouara, NEL
Subsea EXPO 2015 Conference, Aberdeen 11-12th February 2015
Presentation Contents
• Project Objective
• Flowmeter Details, Test Programme
• Overview of Erosion Facility
• Factors Which Affect Erosion
• Results and Conclusions
• Recommendations
• CFD Erosion Modelling
• Summary
NEL Slide 2 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Energy, Oil & Gas Low Carbon Technologies Environment
• Holds UK National Standards for fluid flow & density measurement
• A global centre of excellence in flow measurement, flow systems and fluid
dynamics
• World class research, development, modelling, calibration, consultancy,
measurement and testing
NEL Slide 3 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
NEL
Sand Particle Erosion, - Damage, Wear
• A major issue world-wide in oil & gas
exploration & production piping systems
• Causes major wear, damage to piping,
equipment, components
• Potentially significant errors in flow
metering systems
NEL Slide 4 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
• National Measurement System
• Supported the project:
• ‘To assess the effects of erosion on flowmeters using
performance and diagnostic data’.
• Undertaken by NEL
• This presentation outlines the results, findings, conclusions
NEL Slide 5 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
NMS Flow Programme Project
• 3 different meter types supplied for operation in erosive flow conditions
Test Group 1:
• Turbine meter- 50 DN, nitrite coating
• Venturi meter- 50 DN Βeta ratio 0.75, st/steel
Test Group 2:
• Two 80 DN Coriolis meters ( A & B)
– Bent measuring tubes (different internal designs)
– One meter (A) had Diagnostic parameters through advanced signal
condition monitoring.
NEL Slide 6 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Flowmeters
• Determine flow meter performance using clean water with calibrated
reference meters.
• Install in water/ sand erosive flow facility. Run the meters under
controlled accelerated erosive flow conditions
– sand concentration ~6% by weight
– Graded semi-rounded sand, D50 particle size ~275 microns
– Particles range from <125 microns up to 550 microns
• Clean meters, repeat calibration on clean water.
• Process then repeated
• Review, assess meter performance, Report findings
NEL Slide 7 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Test Programme
NEL Slide 8 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
NEL Erosive Flow Facility
Mixing Tank
Clean water tank
Control Valve
Sample Point
Meter B
Electromagnetic ref meter
Meter A
Pump 1 Pump 2
NEL Slide 9 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Factors Which Affect Erosion
NEL Slide 10 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Erosion Basics – Particle Velocity
• Erosion highly dependent upon particle impact velocity ...
E = K.f V2.6
• Particle velocity; wear = f (velocity)2.6
• Particle size
• Materials of construction
• Particle Impact Angle
• Quantity (mass) of sand, sand concentration, duration
• Sand shape, sharpness, hardness
• Fluid flow regime - liquid, gas, multiphase
• Piping configuration, flow path profile, shape, complexity
• Equipment, component design
NEL Slide 11 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Factors Affecting Erosion Levels
NEL Slide 12 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Results
Venturi Meter- Erosion results
NEL Slide 13 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Test 1 Test 2 Test 3
90 hrs 55 hrs 52 hrs
1136 l/min 1050 l/min (rev) 1214 l/min
-0.55% -0.55% -1.1%
Discharge Coefficient (Cd) drift
• Pressure-tappings eroded internally
(edge not sharp); -ve shift in Cd
• Throat diameter 0.1mm increase
• Divergent section 0.4mm increase
• Slight evidence of ripple erosion
marks on parts of wall.
• Pressure tapping erosion most
significant factor.
0.980
0.985
0.990
0.995
1.000
0 500 1000 1500
Dis
ch
arg
e C
oeff
icie
nt
Flowrate (l/min)
Before test 1 After test 1
After test 2 After test 3
Turbine Meter- Erosion results
NEL Slide 14 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Clean water End Test 1
Meter factor 14.3 pulses/l 13.8 pulses/l
Shift in K factor - -3.5%
Test 1: 44hrs @ 1050 l/min, 6% sand
Blades eroded badly
Bearing support badly eroded
13.6
13.7
13.8
13.9
14.0
14.1
14.2
14.3
14.4
0 250 500 750 1000 1250 1500
Tu
rbin
e k
fa
cto
r (p
/l)
Flowrate (l/min)
Before erosion
After Erosion
Coriolis Meters- Erosion results overall-Volumetric Error
NEL Slide 15 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
-10
0
10
20
30
40
50
60
0 50 100 150 200
Vo
lum
etr
ic E
rro
r (%
)
Erosion Hours
Coriolis Meter ACoriolis Meter B
Test 1 Test 2 (reverse)
Test 3
Test 1 Test 2 Test 3
90 hrs 55 hrs 52 hrs
1330 l/min 1050 l/min (rev) 1214 l/min
Test 1: Meter A, Tube velocity 13.2 m/s
Meter B, Tube velocity 8.7 m/s
• Meter B drifts much less than A
• Rate of Drift proportional to velocity
• Meter A stopped working in Test 3-
later found severe erosion damage
of measuring tubes.
Coriolis Meters- Mass Flow Error Drift
Mass Flow Error Drift - Meter A
• Clean, within 0.1%
• Test 1, +16% drift
• Test 2, +18% drift
• Test 3, meter fails- eroded through
Mass Flow Error Drift – Meter B
NEL Slide 16 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
• Clean, within 0.1%
• Test 1, +2.7% drift
• Test 2, +3.0% drift
• Test 3, +3.6% drift
0
2
4
6
8
10
12
14
16
18
20
0 5 10 15 20 25 30
Ma
ss f
low
Err
or
(%)
Flowrate (kg/s)
after test 2
After test 1
Specification
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 5 10 15 20 25 30
Mass F
low
Err
or
(%)
Flowrate (kg/s)
After test 3
after test 2
After test 1
Specification
Coriolis Meters- Density Error
Density Error Drift - Meter A
• Clean, within 0.05%
• Test 1, -15% drift
• Test 2, -17% drift
• Test 3, meter fails- eroded through
Density Error Drift – Meter B
NEL Slide 17 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
0 5 10 15 20 25 30
Density E
rror
(%)
Flowrate (kg/s)
Specification
After test 1
After test 2
• Clean, within 1.3%
• Test 1, +3.1% drift
• Test 2, +3.5% drift
• Test 3, +4.3% drift
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 5 10 15 20 25 30
Den
sity E
rro
r (%
)
Flowrate (kg/s)
After test 3
After test 2
After test 1
Specification
Coriolis Meters- Volume Error Drift
Volume Error Drift - Meter A
• Clean, within 0.08%
• Test 1, +35% drift
• Test 2, +43% drift
• Test 3, meter fails- eroded through
Volume Error Drift – Meter B
NEL Slide 18 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
• Clean, within 0.02%
• Test 1, -0.55% drift
• Test 2, -0.53% drift
• Test 3, -0.65% drift
0
5
10
15
20
25
30
35
40
45
50
0 500 1000 1500 2000
Vo
lum
etr
ic F
low
Err
or
(%)
Volume Flowrate (l/min)
After test 2
After test 1
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
0 500 1000 1500
Volu
metr
ic F
low
Err
or
(%)
Volume Flowrate (l/min)
After test 3
After test 2
After test 1
Diagnostic Data- Coriolis Meter A
SCP-S Stiffness Diagnostic Parameter
SCP-S Sensitive to erosion wear rate within
meter
• Clean, 0% deviation
• During Test 1, -7% deviation
• During Test 2, -1% change,-8% deviation total
SCP- A Asymmetry Diagnostic Parameter
NEL Slide 19 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
SCP-A Sensitive to Difference in amplitude
between inlet and outlet sensor
• Clean, 0% Deviation
• During Test 1, -4.5% deviation
• During Test 2, +0.5% change,
-8
-7
-6
-5
-4
-3
-2
-1
0
1
% D
evia
tio
n (S
CP
-S)
Erosion Test 1Calibration Erosion Test 2
Diagnostic Data -Coriolis Meter A
PCP-M Multiphase Condition Parameter
PCP-M Multiphase Condition Parameter
• Clean, 0 reading
• 5-6% sand concentration, 800-1000 reading
NEL Slide 20 SUBSEA UK CONFERENCE ABERDEEN 15-02-18
0
200
400
600
800
1000
1200
0 2 4 6
PC
P-M
Readin
g
Sand Concentration (%)
Coriolis Meter A- Inspection end of Tests
NEL Slide 21 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Erosion grooves along inside
wall of measuring tube Inlet tube Outlet tube
Severe wear on outer radius of tube.
Erosion scars on outlet bend
of inner measuring tubes
Coriolis meters- Conclusions
• Mass Flow = f.(Stiffness)
• Erosion reduces stiffness, increases twist in
tubes, +ve drift in mass flow
• Density = f(stiffness/mass)
• Density drift highly dependent upon meter
design, where erosion occurs
• Both meters drifted in opposite directions
• Erosion = f (velocity )^2.6
• Velocity in Meter A tubes (13.2 m/s)
approx 1.5 times higher than Meter B
• This equates to ~ 3 x rate of erosion of
Meter B
NEL Slide 22 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Before
Erosion
After
Erosion
↓
Thickness
↓
Mass
↓
Stiffness
Coriolis meters: Conclusions- Diagnostic Data -Meter A
• Three Diagnostic parameters monitored : – Flow tube stiffness,
– Flow asymmetry
– Multiphase (multicomponent condition) of the fluid
• All sensitive to erosive conditions, wear rate and sand content in the meter
• Potentially use diagnostics to determine when wear has reached a critical
level before risk of rupture
• Diagnostics can potentially detect the presence of sand in the flowstream.
NEL Slide 23 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Accelerated Test v Field Conditions
NEL Slide 24 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Equivalent Field Erosion Conditions
Duration (hrs) Sand conc. by
weight (%)
Accelerated NEL
Erosion Test (1)
90 6
Potential Field
Condition (1)
540 1
Potential Field
Condition (2)
5400 0.1
Recommendations- for flowmeters in erosive flows
• Consider a meter’s maximum operating velocity
• Operate meters at lower velocities to reduce wear rate
• Increase meter size to locally lower velocities through meter
• Use erosion resistant materials to minimise wear
• Perform bench-mark erosion tests on other meter types, designs, – e.g. ‘straight’ Coriolis designs
– Venturi with lower Beta value
• Consider using diagnostics in meters (where possible)
NEL Slide 25 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
• Erosion testing of equipment, components is very beneficial. A good
performance on test is a good omen for a good performance in the field.
• Testing is essential to test seals, bearings and all moving parts
• Accelerated field conditions are simulated under controlled conditions
• Testing quickly identifies any design weak points
• Testing identifies any local erosion hot-spots
• Testing may show surprises, not evident from CFD modelling
NEL Slide 26 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Benefits of Erosive Flow Testing
CFD Erosion Modelling
NEL Slide 27 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
e.g. DNV RPO501- Bend erosion equation
n
pipet
lsand UKG
A
CFmerosion ...
.
).sin().(.
bend geometry
particle size effect
material properties
Particle velocity
mass of sand
n.~ 2.6
NEL Slide 28 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Example Erosion Equation
Test
CFD
NEL Slide 29 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
CFD View: Cone Flowmeter – Water/Sand Erosion
Summary
NEL Slide 30 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
• Flowmeters may wear significantly in erosive flow conditions – Potentially significant shifts in error
– Potential for significant wear of meter internals, loss of meter integrity.
• Wear greatly influenced by meter design, local particle velocities and operating
conditions.
• Erosive flow testing is often essential to understand the wear characteristics of
components and validate equipment performance
• CFD can optimise designs for erosion; predict the wear life of components in
field conditions
• Part of the tool-box for equipment and pipeline integrity, risk and maintenance
management
NEL Slide 31 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Summing Up
Thank You for Listening
Any Questions?
NEL Slide 32 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
NEL Contacts
NEL Slide 33 SUBSEA UK CONFERENCE, ABERDEEN 15-02-18
Audit & Allocation Alick MacGillivray [email protected]
CFD Neil Bowman [email protected]
Densitometers Norman Glen [email protected]
Erosion John Peters [email protected]
Flow Consortium Phil Mark [email protected]
Heavy Oil Chris Mills [email protected]
Measurement Consultancy Craig Marshall
Chris Mills
Measurement Uncertainty Alick MacGillivray [email protected]
Meter Diagnostics Craig Marshall [email protected]
MeterVue Jess Burke [email protected]
Multiphase Holly Ramsay [email protected]
PPDS Norman Glen [email protected]
Single Phase Metering Sarah Pedley [email protected]
Training John Dods [email protected]
Umbilicals Lisa Aagesen [email protected]
Valve Testing John Dods [email protected]
Wet Gas Emmelyn Graham [email protected]
NEL Contact Tel: + 44 (0) 1355 202222
For general queries contact the sales team on [email protected]
Forthcoming Training Courses
• Principles and Practice of Flow Measurement Training Course
12-14 May, East Kilbride
NEL Slide 34 SUBSEA UK CONFERENCE ABERDEEN 15-02-18