chapter 2 pipeline mechanical integrity assesment methodoligies Flashcards
Gas pipeline incident data classified into ___ ______ causes
22 root
one of the 22 root causes is _______
unknown
three time dependent corrosion threats are
external
internal
stress
stable threats due to manufacturing-related threats
defective pipe seams
defective pipes
stable threats due to welding or fabrication related
defective pipe girth weld
defective fabrication weld
wrinkle bend or buckle
stripped threads/broken pipe/ coupling failure
manufacturing-related threats, and welding/fabrication related are _______ threats
stable
Third party/mechanical damage
incorrect operational procedures
weather related and outside force
are all _____ ______ threats
Time-independent
damage inflicted by first, second or third parties
previously damaged pipe
vandalism
are all ______ _______ / ________ threats
third party/mechanical
listed under time independent
incorrect operational procedures
listed under time-independent
cold weather
lightning
heavy rains or floods
earth movements
weather related and outside force
listed under time-independent
identify threat gather integrate data risk assessment integrity assessment mitigation/inspection intervals updated, integrate, and review data reassess risk
seven step conducted to complete the integrity management process.
three generally accepted methods for assessing the integrity of pipelines
In-Line inspections
Hydrostatic pressure tests
Direct assessment
for validating the mechanical integrity of pipelines, used as a strength test and as a leak test
pressure test or
hydrostatic test
a limitation of pressure testing that occurs when a defect survives a higher hydrostatic test pressure but fails at a lower pressure.
pressure reversal
used for liquid lines
MOP
used for gas lines
MAOP
pressure testing can be used on new or
previous installations
the strength test requirements for steel pipeline to operate at a hoop stress of ___% or more of SMYS (specified minimum yield strength)
30
changes that happed slowly over a period of time
creep
line must be reasonably free of air or other entrapped gases.
Line fill
volume and pressure variation ratio (DV/DP)[delta variation/delta pressure]
pre-test calculation
several factors that affect accuracy of test results.
fluid temperature
entrained air
coefficient of thermal expansion
instrument with one psi increments and a calibrated pressure chart recorder
dead weight tester
pressure test advantages
cost effective
eliminates defects
pressure test disadvantages
bacteria stop service safety concerns' root cause not provided no info on remaining defects
an expensive and a non destructive testing tool
ILI InLine Inspection
corrosion detection crack detection geometry self-propelled fluid-propelled cable pulled crawler
types of ILI tools
three primary tools used for specific measurement of pipeline thickness due to corrosion
standard resolution MFL
high resolution MFL
ultrasonic compression wave tool
magnetize the pipe wall. introduces a strong magnetic field into the component wall
standard resolution MFL
more sensors and can discriminate by ID/OD anomalies
high-resolution MFL
distinction between internal and external defects
direct measurement and high accuracy of wall thickness and depth
approximate remaining wall thickness
direct description of anomaly
ultrasonic compression wave tool
ultrasonic crack detection
transverse MFL
elastic wave tools
electromagnetic acoustic transducer (EMAT)
crack detection tools detect longitudinal cracks
send ultrasound in two directions along pipeline to locate and size longitudinal -oriented cracks. ultrasound sent in clockwise and counter clockwise.
elastic wave tools
detection of cracks in dry gas pipelines. oscillates
Electromagnetic acoustic transducer (EMAT)
caliper tools
pipe geometry tools
mapping tools
geometry tools
use a set of mechanical finger/arms detects dents and deformations
caliper tools
like caliper but uses gyroscope to provide o’clock position
pipe geometry tools
used with other tools provide geographical coordinates using GPS. Does XYZ mapping
mapping tools
bends and radius needs to be ____ of the diameter of the pipe
3X
miter bends need ______ or less
12*(12degrees)
valves and other internal obstruction need ______ pieces for diameter change . Have minimum slope of 1:5
transition
ovality needs to be restricted to ____ or less
3%
once an ILI is established can rerun at appropriate intervals to monitor new or changes in _____ amomalies
existing
ILI tools are normally _____ and ______ than normal utility pigs
longer and heavier
a portable or permanently installed device placed on the surface above a pipeline that both detects and records passage on an ILI tool
above ground market (AGM)
a computer system capable of assembling, storing, manipulating, and displaying geographically-referenced information.
Geographical information system (GIS)
_____ ____ provided at tees and wyes when a branch connection is greater than or equal to 50% of the mainline diameter
Guide bars
