OPS ECDA Workshop

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OPS ECDA Workshop

• David Berger Alan Eastman
• KeySpan Corporation
• Pacific Gas Electric
• Houston, TX
• November 4, 2003

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KeySpan Gas TransmissionSystem Summary
Distance (miles)
SMYS

• Less than 20
• 20 to 30
• Greater than
• Totals

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PGE Gas TransmissionSystem Summary
Distance (miles)

• Class 1
• Class 2
• Class 3
• Class 4

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IMP Tools

• Pressure Test
• In Line Inspection (a.k.a. Pigging)
• Direct Assessment (a.k.a. DA)
• Other

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ECDA Process
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ECDA Steps

• Step 1 - Pre Assessment - Dave Berger
• Step 2 - Indirect Examination - D. Berger
• Step3 - Direct Examination - Alan Eastman
• Step 4 - Post Assessment - A. Eastman

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ECDA Step 1 - Pre Assessment

• Determine what you know about the main in
  Question
• Determine what threats are being encountered

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ECDA Step 1 - Pre Assessment

• Determine the Relative Risk of this Segment
• Run Risk Model if Available

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Step 1 Pre-Assessment
Is the ECDA process technically, practically and
economically feasible ?
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IIT Selection Tool Form
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Region Assignment Form
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ECDA Step 2 - Indirect Examination

• Tool Selection based on Pipe and Threats
• Integrate Pre-Assessment information into
  Indirect Exam Process
• Pipe Region
• Tool Types
• Expected Results
• Data Collection

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Step 2 Indirect Examinations

• Other Logistical Issues
• Home owner notification
• CIS through asphalt
• City permits

Dear Landowner, Recently we sent you a letter
notifying you that we would be performing some
testing of the natural gas pipeline on your
property. As a reminder, the testing will not
cause an interruption of your gas service. We
are planning to be testing the pipeline in your
area next week. If we need to gain access to
your backyard, we will contact you in person at
the time of the testing. In the event that
nobody is home, we will plan to come back and
test your property at some future date, most
probably on a Saturday. However, please contact
our testing Contractor, Mears, at 925-820-7630 if
it is acceptable for us to enter your backyard
and perform the testing in your absence. The
testing will only take approximately 5 minutes
per residence. Thanks for your cooperation.
PGE
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25 Interval
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5 Interval
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ECDA Step 2

• Tool Selection based on Pipe and Threats
• Major Threats to LDCs are Corrosion and Third
  Party Damage
• External Corrosion
• Internal Corrosion (Dependent on gas quality)
• SCC Not a Problem
• First and Second party Damage also an issue

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ECDA Step 2

• Integrate Pre-Assessment information into
  Indirect Examination Process
• Check for CP History
• Coating Type and Recent Examinations
• Tool Environment
• Special Situations

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ECDA Step 2

• Pipe Region
• Tool Changes Requires Region Change
• Soil Type and Corrosion History May Change Region
• Coating Type May Change Region
• Pipe Type May Change Region
• Pipe Diameter May Not Change Region
• Threat Change Requires Region Change

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ECDA Step 2

• Tool Types
• CIS DC Electrical
• PCM Near DC but AC
• DCVG DC Gradient
• ACVG Near DC but AC
• Soil Resistivity Corrosion Rates
• Bacterial MIC Presence
• C scan AC Electrical

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ECDA Step 2

• Expected Results
• Based On Threats, What do You Expect to Find
• For Corrosion
• Coating Damage, Disbondment, Shielding
• In Areas with Poor CP, External Corrosion
• With Wet Gas, Internal Corrosion
• Near Dumps, MIC
• Third Party Damage
• Coating Damage (Maybe Pipe Damage)

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ECDA Step 2

• Data Collection
• Manual or Automatic
• Data Storage
• Data Retrieval
• Data Displays

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GM 33
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GM 33
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GM 33

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GM 33

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GM 33

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Part 2

• Now Alan will take you through the next two steps

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Indirect Inspection Classification(example)

• CIS SevereAll of the following must exist
•   Less than 600 mv off
•   200 mv depression over baseline
•   Convergence of on/off potential
•   Other condition that the PE wants to document
•   lt500 off (any case)
•  
• CIS Moderate...All of the following must exist
•   Less than 600 mv off
•   200 mv depression over baseline
•   Other condition that the PE wants to document
•  
• CIS MinorAny of the following can exist
•   Between 600 to 850 mv off
•   Other conditions that the PE wants to document

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Prioritization Criteria
I Immediate S Scheduled M Monitored NI No
Indication
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CGT Scope

• 2192 miles to assess 1673 miles of covered
  transmission lines
• 1,273 miles of ECDA
• (35,177,000)
• 394 miles assessed during 913 miles of ILI
• (98,500,000)
• 6.5 miles of Pipeline Replacement
• (6,500,000)

2004 Scope

• ECDA 117 miles (5.8 million)
• ILI 79 miles (12 million)
• CIS (400,000)
• Pipe Replacement (2,000,000)

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All pipeline companies will allocate the
appropriate resources to ensure the integrity
pipelines with the highest consequences of failure
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Step 3 Direct Examination

• Number of excavations per RP0502
• All immediate indications must be excavated (may
  be re-prioritized after a portion is excavated)
• At least 1 scheduled dig per region
• Effectiveness digs
• First ECDA digs

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Direct Examination

• Inspections
• Remaining Strength Assessment
• Root Cause Analysis
• Reprioritization

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Recategorization
Work In Progress
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Post Assessment

• Remaining Life Calculations
• Re-Assessment Intervals
• ECDA Effectiveness Validation
• Documentation

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Lessons Learned

• Establishment of ECDA procedure has been a corner
  stone of program
• Permit Applications time consuming and
  challenging
• Landowner Notifications time consuming
• Establishing GIS procedure is critical
• IIT methods work
• IIT results has aligned well and is rational
• ECDA process appears to be working well
• We are sure there are more lessons to be learned!!

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Example of an ECDA Line 132 Through Silicon
Valley

• Selection Criteria
• Identified by Risk Management Program
• Primary Threat EC
• Not piggable
• 8 OD changes
• 10 plug valves

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L-132 Near Major Theme Park

• 20 mile section in study area
• 24-34 inch, 400 MAOP, 20 to 40 SMYS, 1944 HAA,
  1974 Tape
• 13 Integrity Management Areas (IMAs)
• 6300 under streets,
• 6000 under concrete,
• 4950 under soil,
• 2300 in paved parking,
• 2150 in backyards

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Results of Classification

• Good alignment between techniques
• CP was protecting poorly coated section of pipe
• Results appear rational

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Results of Prioritization
Total of 10 Excavations
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Example of Line 132 Excavation Data

• Data Element Dig 1 Dig 2
• ECDA Region 132-1 132-2
• Coating Type Wrap HAA
• Pipe-to-Soil (-mV) 1051 971
• Soil Resistivity 684 684
• Coating Condition Partially Disbonded
  Partially Disbonded
• Liquid underneath coating Yes Yes
• Soil pH 5.5 6.0
• Pipe pH 7.4 8.0
• Corrosion No Yes
• Pit Depth (inches) 0.015 to 0.031

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Final Outcome

• 500 feet of recoating
• 1650 feet of pipe replacement
• Remaining indications reprioritized
• Re-assessment interval being determined

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Site Three

• Poor Condition

Excavate 10 ft.
Excavated, removed coating, sandblasted
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ECDA

• The
• End
• (I Thought They would Never Finish)