AMPP ICS flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- CO2 corrosion mechanism
- Dissolved CO2 forms carbonic acid, which cathodically reduces at the steel surface, driving iron dissolution; rate depends on pH, temperature, pCO2, and protective FeCO3 scale.
- H2S partial pressure threshold
- A partial pressure above 0.05 psi generally defines sour service under NACE MR0175/ISO 15156, requiring materials qualified for sulfide stress cracking resistance.
- Galvanic corrosion condition
- Two dissimilar metals in electrolytic contact create a potential difference; the more active metal becomes the anode and corrodes faster, especially with a large cathode-to-anode area ratio.
- Erosion-corrosion definition
- Mechanical removal of protective films or metal by flowing fluid, sand, or droplets accelerates corrosion; severity depends on velocity, flow regime, and solids content.
- MIC mechanism
- Sulfate-reducing and acid-producing bacteria in biofilms generate H2S or organic acids, creating localized pitting under deposits; sessile populations are the key indicator.
- Underdeposit corrosion
- Differential aeration under scale, sand, or debris creates an occluded anode; the small anodic area relative to the external cathode drives deep, compact pits.
- Temperature effect on corrosion
- Corrosion rate typically rises with temperature to a maximum near 60-80 C for CO2 systems, then falls as protective FeCO3 scale becomes stable.
- pCO2 screening threshold
- A CO2 partial pressure above about 7 psi is commonly used as a screening trigger for sweet corrosion evaluation in carbon steel systems.
- Wall shear stress effect
- High shear removes protective films and increases mass transfer, raising corrosion rate; low-velocity stratified flow promotes water dropout and underdeposit attack.
- Chloride effect on scale
- Chloride ions reduce FeCO3 stability and promote pitting; higher chloride content generally increases corrosion risk in CO2 systems.
- H2S IDLH value
- The immediately dangerous to life or health concentration for H2S is 100 ppm; odor fatigue occurs above this level, so monitors and escape sets are required.
- Confined space entry
- Entry into pits, sumps, and tanks requires atmospheric testing for O2, H2S, and flammables before and during entry, plus standby personnel and rescue plans.
- Sour service material requirement
- Materials in H2S service must comply with NACE MR0175/ISO 15156 to resist sulfide stress cracking and hydrogen-induced cracking.
- Fitness-for-service assessment
- Methods such as ASME B31G and API 579 evaluate remaining strength of corroded pipe to set safe operating limits before continued service.
- Coupon weight loss
- Retrievable coupons exposed for a known period give average general corrosion rate by mass loss; pit depth and density must be measured separately for localized attack.
- ER probe principle
- Electrical resistance probes measure metal loss in real time from resistance change; they track general trends but are less sensitive to localized pitting than coupons.
- LPR measurement
- Linear polarization resistance measures instantaneous corrosion rate from the slope of current versus potential; it requires a conductive aqueous electrolyte and is affected by films.
- Iron count interpretation
- Iron concentration in produced water correlates with corrosion rate; spikes indicate increased corrosion or solids carryover and should be trended with production data.
- Pit morphology clues
- Deep compact pits suggest MIC or underdeposit corrosion; elongated pits aligned with flow suggest erosion-corrosion; uniform thinning suggests general corrosion.
- Inhibitor partitioning
- Film-forming inhibitors must partition into the water phase to reach the steel surface; performance depends on water cut, shear, and persistence.
- Water injection treatment
- Deaeration, oxygen scavengers, and biocide programs control oxygen corrosion and MIC in injection systems; SRB control may use nitrate or nitrite treatments.
- CRA selection factors
- Corrosion-resistant alloys such as 13Cr, duplex, and nickel alloys reduce mitigation burden but must be qualified for chloride SCC and sour service conditions.
- Internal coating function
- Coatings and linings isolate steel from electrolyte; holiday and defect inspection is essential because failures localize attack at coating breaks.
- pH stabilization
- Raising pH promotes protective FeCO3 scale and reduces CO2 corrosion rate; requires water chemistry control and monitoring to avoid scaling or cracking risks.
- Non-intrusive ultrasonic monitoring
- Permanently or temporarily mounted ultrasonic sensors track wall thickness without hot work or shutdown, supporting periodic or continuous corrosion monitoring.
- Smart pig inspection
- Instrumented inline inspection pigs map metal loss along the pipeline; they require piggable geometry and provide high-resolution wall-thickness data.
- Risk-based inspection
- RBI allocates inspection resources by likelihood and consequence of failure, aligning monitoring and inspection frequency with risk ranking.
- Failure analysis sequence
- Collect background, inspect the failure site, characterize morphology, analyze deposits and fluids, then test hypotheses to distinguish mechanism from contributing factors.
- Deposit analysis methods
- XRD, SEM, and EDS identify corrosion products such as FeCO3, FeS, and Fe3O4, indicating scale protectiveness and corrosion mechanism.
- Program KPI examples
- Key performance indicators include corrosion rate targets, inhibitor availability, inspection coverage, and corrective action closure rates for program effectiveness.
- Management of change
- MOC ensures process, material, or chemical changes trigger re-evaluation of corrosion risk, mitigation, and inspection plans before implementation.
- Record retention requirement
- Corrosion control records must be retained per regulatory requirements and long enough to support audits and failure investigations; retention periods vary by jurisdiction.