- 1. Pipeline Integrity Assessment
2. ? GNP 4% (1999) 1/3 3. Summary of Incident CausesASME Causes
of Gas Transmission IncidentsThird Party Damage External
CorrosionInternal Corrosion Natural Forces MiscIncorrect OperationI
tO tiUnknown Other FailuresNon-Pipe Constr/Instal PipeMfr Prev.
Damgd PipeMalfunctionStress Corrosion Cracking Vandalism 0.0 2.0
4.06.08.0 10.0 12.0 14.0Avg Annl Incidents, 85-01 4. COST OF
CORROSION $5.0 bil. $5 0 bil Department of Transportation (DOT),
USA, 2001 ($276 bil.)4 5. Cost Estimate Example Offshore PNG
PipelineCost (US $ Million)CMilli )Category 7.4 MPa8.4 MPa 10 MPa12
MPaBare Pipe Materials 374.1314.4296.5 228.8External Coating 44.1
44.1 44.142.0Internal Coating 21.2 21.3 21.221.2Weight Coating 67.2
67 2 63.763 7 57.8 57 854.0 54 0Cathodic Protection20.7 20.5
20.520.2Pipe Laying80.7 78.1 80.880.8Dredging& Backfill 17.7
17.1 16.816.1Mobil. & Demobil.8.48.4 8.48.4Total 634.1634
1567.6 567 6546.1546 1 471.5471 5 10 15% of total direct
construction cost for corrosion protection (coating + CP) (Cited
from Feasibility Study Report for Irkutsk PNG pipeline) 6. 7. CASE
HISTORIES ON UNDERGROUND CORROSION Corrosion on the pipeline
Corrosion on the bottom plates of aboveground storage tank 8.
CORROSION IN ANAEROBIC SOIL 9. Chemical/microbiological corrosion /
Electrical corrosion 10 10. (corrosivity) , , 11. vs. 3 3
3P/SDisbonded areaSulfate 2 2 2P0P0P0 1 1 1 0 0 0 -2.0 20-1.818-1.6
16 -1.4 14-1.212 -1.010 0 20 406080 100 120100110 210 310 410P/S
(V/CSE) Disbonded Area (cm ) 2 2- [SO4 ] (mg/g of soil) 3pH
SRBResistivity 2 2 2P0P0P0 1 1 1 0 0 4 567 89 103 4 5 67 89010 10
101010 1010 101 10 23 10 410 pHSRB (cells/g of soil) Resistivity
(Ohm.cm) 12. Soil Resistivity Wenner 4-Pin Resistivity Measurement
I E S S S . = RA/L (cm) () 13. 4-pin method Soil box 14. SOIL
RESISTIVITY SURVEY: EQUIPMENTS 15. Soil pin . . a/2 . 16. 5 000 ohm
cm5,000 ohm.cm 17. ()1.E+061.E+051 E+05 Soil Resistivit (.cm)
ty1.E+04 S1.E+03 corrosive1.E+02 010 20 30 40 50 607080 90 100 110
120 130 Distance (km) 18. ABA,A B ?19 19. SOIL RESISTIVITY SURVEY:
DEPENDENCY ON SOIL DEPTHA. .B. . .C. .D. 20 20. SOIL RESISTIVITY
SURVEY: BARNES METHOD Th1 1h2 2h3 3Sh4 4h5 51 1 1 1 S R R1 R 2Rn 21
21. SOIL RESISTIVITY SURVEY: BARNES METHOD 4m1 1 1 R 4 R 2 R 2 4 R2
R41. 2m, 4m R 2 4 (R2, R4) R2 R42. R2-4 R2 R42 4 400 3. 2-4 R2 R4
22 22. SOIL RESISTIVITY SURVEY: BARNES METHOD Pin 2m R2 = 6.3 Pin
4m R4 = 1.3 2m 2= 22006.3=7,917 cm 2m 4= 22006.3=3,267 cm 2-4 =
400(R2R4)/(R2-R4)= 400(1.36.3)/(6.3-1.3)00 ( 3 6 3)/(6 3 3)= 2,061
Test dataBarnes Analysis a (cm) R (Ohms) Avg. 1/R(1/R)Layer R Layer
2006.37,9170.16 - 6.3 7,9174001.33,2670.770.611.64 2,061 23 23.
SOIL RESISTIVITY SURVEY: BARNES METHOD Test data Barnes Analysis a
(cm)R (Ohms)1/R(1/R) Layer RLayer 150 1.10.91 - 1.11,040 300
0.891.10.19 5.34,995 450 0.462.21.10.91858 600 0.14 0 147.1 71
4.949 0.20 0 20190 7500.083 124.90.20190 9000.076 131.01.094Ref.)
T.H. Lewis, Jr., Deep Anode Systems, NACE (2000) p.7-1124 24.
(sulfate (sulfate- reducing bacteria; SRB) 25. CORROSION IN
ANAEROBIC SOIL 26. SULFATE-REDUCING BACTERIA (SRB) SO42-SO42 + ATP
2- APS + PPiPiEnters cell 2e-SO32- + AMP H+S2O52- Metabisulfite 2e-
Outside cellS2O42- DithioniteS2- S2O32-S3O62- Trithionate
2e-2e-Thiosulfate Anaerobic bacteria Neutral environments Reducing
sulfate to corrosive sulfides27 27. SRB Population vs. Soil Key
Parametersp y99 910 10 10108 Resistivity10 8 810 Redox potential 7
7710 1010 6 6ells/g of soil) 10 10cells/g-soil) cells/g-soil)610 5
5 10 10510 4 4 10 10 SRB (cSRB (ceSRB (c410 3 3 10 10310 2 2 10
10210 10 1 110101 10 0 Clay content010234 5 6 10 10 1010100 1020 30
405060-0.20.0 0.2 0.4 0.6 0.8 ( cm)Clay Content (%)Eh (V/NHE)9910
10810 8 10Anaerobic,710 7 10106Neutral, /g-soil)/g-soil)10510 6High
clayey,Low resistivity,L i ti it SRB (cells/APB (cells/410 5High
water content 10310 4 10210 3110100Water content APB 210 10 234 5 6
7 890 102030405010 10 10 10 10101010 Water Content (%) SRB
(cells/g-soil) 28. Corrosion vs. E C i Exposure TiTime A-0.4
0425mSRB -activeBiocide addedC 2A -active PB V/SCE)-0.6Counts (Arb.
Unit) U Ecorr (mV 1 OFe P-0.820m S FeFe CAlSi 0 0 2 46 810 Energy
(keV) -1.0 10 0.4orrosion Rat (mm/y)0.36m /y m0.3B D te0.2
2m0.12.020m Co2.0 1.5 S0.0OCounts (Arb. Unit)1.5 0 50100150 200 Fe
1.0Tim (Day) eCoun (Arb. Unit)Fe Fe1.0O S 0.5 C P ntsSi Fe0.5 Fe Si
0.0 P 0 2 46 810 CAl FeEnergy (keV)0.0 0 2 46 810 Energy (keV) 29.
MIC in Aerobic Condition2.01.5 Arb. Unit)1.0 FeOS Counts (A0.5FeSi
PCAl Fe0.00002 4 68 10 Energy (keV) SRB 30. CP CP SRB-active soil
Ref.) K. Kasahara, et al.,Corrosion, 55(1) (1999) 742H 2O 2e H 2 2
OH The change of local chemistry at metalsurface, inducing an
increase of pH. Effective tool for prevention of SRB-induced MIC in
soil. 31 31. CP vs. MIC vs 32 P010-2.0 -1.8-1.6-1.4 -1.2 -1.0 P/S
(V/CSE) Despite of coating and CP, MIC occurred. All corrosion
occurred the region under the disbonded coating. 32. Pt &
Reference~15cm depth 15cmRef1Pipe Ref2 Pt 1. Ref 1 vs. Pipe 2. Ref
2 vs. Pipe 3. Ref 2 vs. Pt 33 33. PotentialmV vs. Cu/CuSO4 P/S-1430
(-1200) In Crevice I C i-610 ( 500) 610 (-500) Pt Electrode -480
480 Redox-160 (vs. NHE)*1*1. At pH 7 34 34. ANSI/AWWA < 700 700
- 1000 108 1000 - 12005(polyethylene 1200 - 1500 1500 - 200021
encasement) > 2000 0 pH 0-25 10 2-43 4 - 6.50 6.5 - 7.5 0** 7.5
- 8.50 > 8.53 (mV) > 1000 50 - 1003.5 0 - 50 4 DIN 50929
20,000S*M*M*NI* 2: 1 1 + CIPSI*S*M*NI CIPS SevereI S S MModerateI S
M MMinor I S M NINIS M M NI* I: Immediate ( ) S: Scheduled ( ) M:
Monitoring ( ) ), ), 133. (2 poor coating) (minor) (moderate)
(severe) CIPS -0.75V < off < -0.65V Off > -0.65V >
10,000 cm 5,000 10,000 cm< 5,000 cm CIPS I II III IV V 134. / pH
p () 135. () ( monitoring )(monitoring) Coating defect found No
disbonding Defect was protected perfectly by CP. 136. ()
(scheduled) Disbonded areaMechanical Damage Coating disbondmentNo
corrosion at crevice openingCrevice opening: pH>11Corrosion
occurred inside creviceInside crevice: pH 6-7Depth of disbondment:
about 15 cm. 137. () ( immediate )(immediate) pHSTN (mV) (cm)
:10,362cm2 17 -604 6046,5136 513:56cm2: 12 :25 ~ 70 2 25 70cm 2
7~9-7352,098: 12, 7 :10,362cm2 38 -5622,538:1,602cm2 :5.4 ~ 6.1cm2,
4 8~9-7011,360 , :7.6cm2~47cm2 138. Is corrosion is active or
passive? CASE 1: Active corrosion CASE 2: Passive corrosion Types
Potential (mV/CSE) Pipe-to-Soil Potential-1430 to -1200 Potential
inside crevice-610 to -550OFF 139. pH 2H 2O 2e H 2 2OH pH 1) , OH-
pH 2) pH ( ) 3) pH pHpH pH>10~11 , . vs. pH p .pH< 8 , pH .
140. 4 4. ECDA 141. Maximum pit depth/burial time 0.4 mm/y*1 0.30 3
mm/y at l/ least 40mV CP 0 CLPR measurement (ASTM G59) + pitting
indexCorrosion coupon*1. Upper 80% confidence level of maximum
pitting rates for long term (up to 17y) underground corrosion tests
ofbare pipe coupons without CP in a variety of soils including
native and non-native backfill. 142. RL 0.85SM tPFAIL PMAOPGR SM
FOR:PYIELD PYIELDSM (safety margin) = 0.6GR () = 10 mil/yr. () /y 0
.330T () = 0.330RL 0 .85 (. 6 ) 16 .8 yr .010 1/2 ECDA !!! 143.
144. ECDA DCVG . DCVG , ECDA . . DCVG ECDA . ECDA , , feedback 145.
Availability of ECDA Tools (cf NACE RP0502) (cf.CIPS DCVG Pearson
EM AC AttenuationCoating holidays 2 1,22 2 1,2Anodic zone or bare
pipe 23 3 33Near river or water crossing 23 3 22Under frozen
ground33 3 2 1,2Stray currentsS2 1,2 12 2 2 1,212Shielded corrosion
activity (heat-shrink sheet)33 3 33Adjacent metallic structures 2
1,23 2 1,2Near parallel pipelines2 1,23 2 1,2Under HVAC overhead
electric transmission lines2 1,22 33Shorted casing 22 2 22Under
paved roads33 3 2 1,2Uncased crossing 2 1,22 2 1,2Cased piping 33 3
33At deep burial locations 22 2 22Wetlands (li it d)W tl d
(limited) 2 1,2 12 2 2 1,212Rocky terrain/rock ledges/rock
backfill33 3 22*1: - (
