Corrosion Monitoring Techniques Flashcards
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Read the first 7 Corrosion Monitoring Techniques flashcards as text
Electrochemical Noise (EN) monitoring detects corrosion by measuring:
Answer: Spontaneous fluctuations in potential and current that reveal corrosion mechanisms
EN monitoring captures natural, low-level fluctuations in electrochemical potential and current that serve as fingerprints for corrosion mechanisms including pitting and stress corrosion cracking.
A Zero Resistance Ammeter (ZRA) is used in corrosion monitoring to measure:
Answer: Galvanic current flowing between two dissimilar metals coupled together
A ZRA measures the galvanic current between two coupled metal electrodes while maintaining zero resistance in the coupling circuit, accurately simulating real galvanic couple behavior.
The Field Signature Method (FSM) monitors corrosion by:
Answer: Mapping wall thickness changes using an array of pin electrodes that measure resistance patterns across a pipe section
FSM uses an array of pins welded to the pipe and measures electrical resistance patterns between them, creating a 'signature' that reveals localized wall thickness changes and corrosion distribution.
What is the main advantage of online corrosion monitoring over offline inspection methods?
Answer: Online monitoring provides continuous data without removing equipment from service
Online monitoring enables continuous, real-time data collection while the system remains in service, allowing early detection of corrosion upsets and trend analysis without production interruption.
When calculating corrosion rate from a corrosion coupon, which piece of data is NOT required for the standard calculation?
Answer: Ambient temperature during the exposure period
The standard coupon corrosion rate formula uses mass loss, surface area, metal density, and exposure time; ambient temperature affects corrosion but is not a variable in the rate calculation equation itself.
What is a key limitation of Linear Polarization Resistance (LPR) probes that restricts their application?
Answer: They require a conductive electrolyte and are unreliable in low-conductivity environments
LPR is an electrochemical technique that requires ionic conductivity in the surrounding medium; in low-conductivity, dry, or predominantly hydrocarbon environments, LPR measurements become inaccurate.
Sand/erosion monitoring probes are deployed in corrosion monitoring programs primarily to detect:
Answer: Mechanical metal loss caused by particle impingement distinct from electrochemical corrosion
Sand/erosion probes detect metal loss caused by mechanical abrasion from entrained sand, proppants, or other solids, which is a distinct failure mechanism from electrochemical corrosion.