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Best Practice
Corrosion/Erosion Monitoring
and
Critical Process Indicators
Salton Sea KGRA
by Dr. Dan Hoyer, PEVeizades & Associates, Inc.
1
Monitoring
Degradation
of Materials
Outline
VEIZADES & ASSOCIATES, INC.2
Challenges in
High Temperature
Corrosion
Scaling Resources
Materials of
Construction
SPE/GRC Workshop March 21-27, 2017
Process
Indicators
Salton Sea Geothermal Fluids
Hot (>500°F)
High chloride content (>10%)
High total dissolved solids (>25%) with high scaling tendency
Noncondensible gases (ammonia, carbon dioxide, hydrogen sulfide)
Corrosion rates:
– can exceed 300 mils per year for carbon steel
–much higher corrosion rates if aerated or acidified brine
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VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
Process Flow Diagram (PFD)
4VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
Material of construction
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VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
Material Location
Titanium Grade 29 Production Wells
Inconel 625 (58% Ni, 23% Cr), Inconel 825
Vessel
2507 Duplex Stainless Steel(25% Cr, 7% Ni, 4% Mo), 2205
Piping
2507 Duplex Stainless Steel Injection Wells
316L Stainless Steel Condensate/NCG
Cement Lined Injection line
Carbon Steel Non-aeratedbrine tank
Price
Expected
Service Life
Materials of Construction
6VEIZADES & ASSOCIATES, INC.
SPE/GRC Workshop March 21-27, 2017
Monitoring is essential for safe and sustained operation
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General corrosion/erosion Ultrasonic Thickness Testing (UT)
Pitting or “bear claw” corrosion Visual, B scan or C scan UT
Stress Corrosion Cracking (SCC) Visual, Dye Pen, Magnetic Particle Inspection, Shear wave UT
Degradation Mechanism Inspection Technique
VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
Process Indicators
VEIZADES & ASSOCIATES, INC.8
Process Indicator Potential Consequence
Chemical monitoring:-increase in chloride/silica in steam-decrease of pH in condensate
Higher potential for stress corrosion cracking (SCC) and corrosion
Pressure change vs. time Scaling or erosion
Log book of upset conditions Target inspection
SPE/GRC Workshop March 21-27, 2017
Degradation type, knowledge of service and risk of failure drives inspection
VEIZADES & ASSOCIATES, INC.9
SPE/GRC Workshop March 21-27, 2017
Major Overhaul Inspection
– Visual, pictures and thickness measurements at all process changes
– Additional inspection if there is a potential to crack
More Frequent Inspections if:
– New plant; one year after start-up
– Poor understanding of degradation mechanism
– Process parameters outside design
Sustained Inspection
– Baseline prior to start-up
– Same location for each major overhaul inspection
– Evaluate corrosion rate (mils per year) changes over life of project
Corrosion
Accelerated corrosion of weld zones in alloys
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VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
Example of selected inspection
locations and frequency
Turbulence
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increased turbulence/velocitym
ixed
fluid
s
VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
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VEIZADES & ASSOCIATES, INC.
John Featherstone-
Inventor of
Crystallizer/Clarifier and
Dr.Dan’s Mentor
Scale does not
adhere to
alloys. Easy
to remove and
clean.
SPE/GRC Workshop March 21-27, 2017
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Well Casing
Pressure Test
Video Camera
Multiple Finger Caliper
VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
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Massive pitting in
HP steam line
from wash water
impurities
Weld failure on
steam vessel
internals
VEIZADES & ASSOCIATES, INC.SPE/GRC Workshop March 21-27, 2017
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VEIZADES & ASSOCIATES, INC.
UT Inspection Matrix – Carbon Steel
Evidence of changes in physical and
chemical depositional environment
SPE/GRC Workshop March 21-27, 2017
Summary
Materials of construction can mitigate impacts
Monitoring is critical to sustained operation
Anticipated degradation process and risk of failure directs
frequency and inspection technique
VEIZADES & ASSOCIATES, INC.16
Physical
Chemical~
Erosion
Corrosion
SPE/GRC Workshop March 21-27, 2017
