iii sinha iocl

Structure of Presentation

Pipelines division: an overviewPipeline health monitoringPipeline protections measures.Pipeline coating.Cathodic protectionPipeline surveysPipeline repair Station/Mainline facilitiesMaintenance philosophy.Case studies

Pipeline network having total length of 10330 km, comprising pipelines of sizes ranging from 8” to 48” dia and 72 MMTPA (1.44 Million bpd) capacity

72 installations across India

3 Single Point Mooring systems

63 bulk crude storage tanks (approx. total capacity 25 Million bbl)

Dedicated Telecom (with over 6,500 km OFC), SCADA system

Pipelines Division of IndianOil : Assets

Growth of Pipeline Length

435

2014

39805423

6364

7730

10330

0

2000

4000

6000

8000

10000

12000

1964 1975 1985 1996 2000 2004 2009

Length ( KM)

KM

YEAR

Age Profile of IndianOil’s Existing Pipelines

2200 km(25-40 Years)

1800 km(> 40 Years)

3800 km(<10 Years)

2500 km(10-25 Years)

IOCL PIPELINES•• IOCL pipelines, those commissioned in 60IOCL pipelines, those commissioned in 60’’s have s have

already served for more than 40 years and still being already served for more than 40 years and still being operated at Max. allowable operated pressure & operated at Max. allowable operated pressure & achieving the yearly throughput target.achieving the yearly throughput target.

•• Implementation of effective corrosion prevention Implementation of effective corrosion prevention programme has helped in achieving the safe, programme has helped in achieving the safe, economical & reliable operations of pipelines.economical & reliable operations of pipelines.

Why do pipelines fail?Why do pipelines fail?

• Causes of pipelines failures– Third party damage– Corrosion (Internal/External)– Construction/Material defect– Natural Calamities/Ground movement– Other causes (operational error)

Failures in Failures in IOCLIOCL’’ss Operating Pipelines Operating Pipelines

0

10

20

30

40

50

Mech/Materialfailures

Corrosion failures

Thirdparty/Pilferages

failures

Others

P/L FAILURES%

Integrity Management of Pipelines Spillage of oil

& Fire hazard

Interruption in petroleum

supply

Environmentaldamage

near leak spot

Legal Issues,Financial Loss

Pipeline Failure:

Consequences

Identification of possible causes of Pipeline corrosionIdentification of possible causes of Pipeline corrosion.

Major Causes of Pipeline External Corrosion :Major Causes of Pipeline External Corrosion :--Poor/defective Coatings.Poor/defective Coatings.Inadequate Cathodic Protection (CP).Inadequate Cathodic Protection (CP).Coating defects combination with inadequate CP.Coating defects combination with inadequate CP.Interference due to external agencies. Interference due to external agencies. Stress & Bacterial corrosion.Stress & Bacterial corrosion.

Major Causes of Internal Corrosion :Major Causes of Internal Corrosion :--Corrosive nature of fluid transported through Corrosive nature of fluid transported through pipeline.pipeline.Erosion Erosion –– Corrosion.Corrosion.Localized Chemical attack/bacterial corrosion. Localized Chemical attack/bacterial corrosion.

Prevention Against Corrosion : ApproachPrevention Against Corrosion : ApproachIdentification of possible causes of corrosionIdentification of possible causes of corrosionEvaluating approaches / methods to deal with Evaluating approaches / methods to deal with corrosioncorrosionSelecting Corrosion Monitoring & Mitigation Selecting Corrosion Monitoring & Mitigation methods comprising CP and diverse coating methods comprising CP and diverse coating solutionssolutionsDealing with challenges in achieving effective Dealing with challenges in achieving effective corrosion mitigation measurescorrosion mitigation measuresInstituting an effective corrosion mitigation Instituting an effective corrosion mitigation programme and experience sharingprogramme and experience sharing

Integrity Management Practices in Indian OilIntegrity Management Practices in Indian Oil

Integrity Management Practices in Indian OilIntegrity Management Practices in Indian Oil

Thrust Thrust AreasAreas

MonitoringPipeline Integrity

MonitoringCathodic

Protection Monitoring

Coating

Selecting Corrosion Mitigation methods.Selecting Corrosion Mitigation methods.

Mitigation Of External Corrosion in Pipelines:i) Protective Coating•• Effective coating/painting on metal structures is the Effective coating/painting on metal structures is the

best and most economical way of corrosion control.best and most economical way of corrosion control.

•• For crossFor cross--country pipeline, the primary protection is country pipeline, the primary protection is coating .coating .

•• Coating isolates the metal surface from contact with Coating isolates the metal surface from contact with the surrounding & avoid corrosion.the surrounding & avoid corrosion.

Plant CoatingPlant Coating–– Coal Tar Enamel CoatingCoal Tar Enamel Coating–– 3 Layer Polyethylene Coating3 Layer Polyethylene Coating–– Fusion Bonded EpoxyFusion Bonded Epoxy–– DualDual Fusion Bonded EpoxyFusion Bonded Epoxy

Field Coating/Refurbishment CoatingField Coating/Refurbishment Coating–– Coal Tar Enamel CoatingCoal Tar Enamel Coating–– Hot Applied Coal Tar Enamel TapeHot Applied Coal Tar Enamel Tape–– Cold Applied TapeCold Applied Tape–– Polyurethanes coatingPolyurethanes coating–– Epoxy CoatingsEpoxy Coatings

Pipeline CoatingsPipeline Coatings


Mitigation Of External Corrosion in PipelinesMitigation Of External Corrosion in Pipelines::ii)ii) Cathodic Protection (CP)Cathodic Protection (CP)

•• CP is a viable tool for Corrosion prevention. CP is a viable tool for Corrosion prevention. •• Corrosion is an electrochemical phenomenon, Corrosion is an electrochemical phenomenon,

therefore effectively mitigated by altering the therefore effectively mitigated by altering the electrochemical condition.electrochemical condition.

•• CP achieved by reversing natural corrosion current CP achieved by reversing natural corrosion current with the supply of current from external source.with the supply of current from external source.

•• The external current supply in CP system is The external current supply in CP system is generated either by sacrificial anode or impressed generated either by sacrificial anode or impressed current system. current system.

Cathodic Protection Station

PSP profile

0.550.650.750.850.951.051.151.251.351.451.551.651.751.851.952.05

0 .25 0

2 .01 5

4 .92 6

1 1. 3 3

31 1

. 6 34

1 1. 8 1

81 6

. 6 37

1 9. 6 3

72 6

. 2 50

2 9. 4 9

13 2

. 5 00

3 3. 1 1

83 6

. 1 00

3 7. 9 0

04 3

. 8 00

4 5. 8 0

04 7

. 7 60

5 0. 3 9

05 2

. 6 46

5 4. 3 9

05 7

. 4 40

5 9. 0 1

66 5

. 1 56

CHAINAGE (KM)

PSP

VO

LT (-

)

Qtr:2nd (April.-June 2006)OFF PONTIALDATUMPPMAX


Coating And Cathodic ProtectionCoating And Cathodic Protection

•• Ideally, perfect coated pipe should not take Ideally, perfect coated pipe should not take any current.any current.

•• However, even newly coated pipe requires current However, even newly coated pipe requires current for making it above protection. for making it above protection.

•• The modern pipeline corrosion control workThe modern pipeline corrosion control workComprises the use of good coatings in combination Comprises the use of good coatings in combination with suitable CP system as the main lines of defense.with suitable CP system as the main lines of defense.

•• Supplementary defense, such as use of insulatedSupplementary defense, such as use of insulatedcoupling, interference mitigation device, local coupling, interference mitigation device, local environmental control etc. reinforce the main defenseenvironmental control etc. reinforce the main defense..

Selecting Corrosion Mitigation methods.Mitigation Of Internal Corrosion in PipelinesMitigation Of Internal Corrosion in Pipelines::Main Contributing factorsMain Contributing factors•• Corrosive nature of the transported product.Corrosive nature of the transported product.•• Moisture/Traces of water, Moisture/Traces of water, COCO22, oxygen, H, oxygen, H22ss, bacteria etc. , bacteria etc. •• Erosion Erosion -- Corrosion.Corrosion.

Mitigation MeasuresMitigation Measures•• By regular and periodic pigging of pipeline for internal By regular and periodic pigging of pipeline for internal

cleaning.cleaning.•• Introduction of corrosion inhibitor in pipelineIntroduction of corrosion inhibitor in pipeline•• Ensuring transported product free from moisture & Ensuring transported product free from moisture &

corrosive compound.corrosive compound.

I.I. Over the ditch coating :Over the ditch coating :-- Old pipelines such as GSPL, Old pipelines such as GSPL, BKPL, HMRB, KAPL, SMPL, MJPL are having over the ditch BKPL, HMRB, KAPL, SMPL, MJPL are having over the ditch CTE coating.CTE coating.

II.II. Plant Coating :Plant Coating :-- Since the mid 90Since the mid 90’’s, plant / yard coating is s, plant / yard coating is being adopted for new Pipelines. being adopted for new Pipelines.

In KBPL, for the first time, 3LPE coating was appliedIn KBPL, for the first time, 3LPE coating was appliedSonipatSonipat –– Meerut branch line was coated with FBEMeerut branch line was coated with FBEKoyaliKoyali –– RatlamRatlam line was coated with DFBEline was coated with DFBE

III.III. Experience of yard / plant coatingExperience of yard / plant coatingControlled condition for applicationControlled condition for applicationGood surface cleaning due to shot blastingGood surface cleaning due to shot blastingBetter inspection and testingBetter inspection and testingLess current requirement for CPLess current requirement for CP

Pipeline Coatings Pipeline Coatings –– Types employed in IOCLTypes employed in IOCL

Performance of Coatings employed in Performance of Coatings employed in IOCLIOCL’’ssPipelinesPipelines

I.I. Over the ditch coatingOver the ditch coating :: Coating condition of certain old Coating condition of certain old pipelines having over the ditch CTE coating are not pipelines having over the ditch CTE coating are not satisfactory at many locations/stretches (current density >500 satisfactory at many locations/stretches (current density >500 μΑμΑ/m/m22).).

Few leaks due to soil/external corrosion were also Few leaks due to soil/external corrosion were also experienced. experienced.

To achieve complete line protection of these pipelines & avoid To achieve complete line protection of these pipelines & avoid soil corrosion/leak, large scale refurbishment of existing soil corrosion/leak, large scale refurbishment of existing coating is being carried out.coating is being carried out.

II.II. Plant Coating :Plant Coating : Since construction of KBPL (1995), plant Since construction of KBPL (1995), plant coating is being adopted for all new Pipelines. coating is being adopted for all new Pipelines.

Performance of all the plant coated pipeline is quite Performance of all the plant coated pipeline is quite satisfactory. All these pipelines are satisfactory. All these pipelines are cathodicallycathodically protected protected and current density of pipelines are quite satisfactory (<100 and current density of pipelines are quite satisfactory (<100 μΑμΑ/m/m22).).

DIADIA(inch)(inch)

LENGTHLENGTH(km)(km)

TYPE OF TYPE OF COATINGCOATING

YEARS IN YEARS IN SERVICESERVICE

(year)(year)

AVG. CURRENT AVG. CURRENT DENSITYDENSITY((μμA/mA/m22))

LINE 1 12 800 Over the Ditch CTE

42 400-500

LINE 2 24 800 Over the Ditch CTE

30 400-800

LINE 3 18 950 CTE(Plant Coated)

10 8-10

LINE 4 22 950 3LPE 13 13-15

LINE 5 10 110 3LPE 13 5-7

LINE 7 10 170 FBE+CTE 6 10-15

LINE 6 10 70 FBE 9 40-50

Current Densities of different coatings in IOCL Current Densities of different coatings in IOCL Pipelines Pipelines

Dealing with challenges in rehabilitation Dealing with challenges in rehabilitation of old operating pipelines.of old operating pipelines.

ChallengesChallenges•• Mostly CTE (over the ditch) coatedMostly CTE (over the ditch) coated•• High current density i.e poor coating.High current density i.e poor coating.•• Conventional CP system.Conventional CP system.•• Inconsistent SEB Power availability/Theft of Solar Inconsistent SEB Power availability/Theft of Solar

panels. panels. •• Highly corrosive soil.Highly corrosive soil.•• Low frequency ERW mainline pipes.Low frequency ERW mainline pipes.

Requirement of Coating SurveysRequirement of Coating Surveys

•• Coating deteriorates with passage of time & the load Coating deteriorates with passage of time & the load on CP system increases day by day.on CP system increases day by day.

•• It slowly reaches a limiting condition where any It slowly reaches a limiting condition where any amount of additional CP protection does not improve amount of additional CP protection does not improve the situation. the situation.

•• Therefore, identification of coating defects with Therefore, identification of coating defects with highest accuracy becomes very important, so that highest accuracy becomes very important, so that coating repairs & subsequent Line Protection is coating repairs & subsequent Line Protection is achieved in shortest possible time.achieved in shortest possible time.

Selecting suitable SurveysSelecting suitable SurveysCURRENT ATTENUATION TECHNIQUE (CAT)CURRENT ATTENUATION TECHNIQUE (CAT)

Over all assessment/classification of coating quality for different stretches.

Most Suitable coating surveys for priority fixing for coating refurbishment.

DC VOLTAGE GRADIENT SURVEY(DCVG)DC VOLTAGE GRADIENT SURVEY(DCVG)

DCVG for pin pointing the coating defects.

APPROACH

Combination of CAT & DCVG for coating assessment & Combination of CAT & DCVG for coating assessment & finalizing locations for refurbishment.finalizing locations for refurbishment.

CIPS Survey CIPS Survey

Reflects the actual status of line protection for entire section.Indicates interference problems, if any.Detects deficiencies in CP system that go undetected during routine monitoring.

Selecting suitable SurveysSelecting suitable Surveys

DC VOLTAGE GRADIENT SURVEY(DCVG)

CURRENT ATTENUATION TECHNIQUE (CAT) SURVEY

Coating SurveysCoating Surveys

BASED ON DB LOSS OBSERVED FOR PIPELINE, COATING DEFECTS CAN BE CLASSIFIED AS UNDER :

SL. NO.

DB/KM LOSS CLASSIFICATION

1.0 < 10 DB/KM GOOD COATING

2.0 10 – 25 DB/KM FAIR COATING

3.0 25 – 70 DB/KM BAD COATING

4.0 ABOVE 70 DB/KM MASSIVE DEFECT

CAT SURVEY

Experience of IOCL

•• CAT is excellent in prioritizing the coating rehabilitation of oCAT is excellent in prioritizing the coating rehabilitation of old ld pipelines (poor coating).pipelines (poor coating).

•• DCVG is very effective for detection of all the coating defects DCVG is very effective for detection of all the coating defects of of newly coated pipelines or well coated pipelines.newly coated pipelines or well coated pipelines.

•• Combination of CAT, DCVG & CIPS is very effective & Combination of CAT, DCVG & CIPS is very effective & beneficial i.e. identifying coating defect, line protection, beneficial i.e. identifying coating defect, line protection, interference study etc.interference study etc.

Experience of IOCL

•• Pipeline metal loss features identified by IPS were plotted Pipeline metal loss features identified by IPS were plotted with the results of CAT/DCVG/CIPS & based on result, with the results of CAT/DCVG/CIPS & based on result, priority made for coating refurbishment & job executed.priority made for coating refurbishment & job executed.

•• Other parameters such as Other parameters such as current densitycurrent density, , soil resistivitysoil resistivity, , age & type coatingage & type coating, , leak/corrosion historyleak/corrosion history etc were also etc were also plotted along with CAT/DCVG/IPS data. plotted along with CAT/DCVG/IPS data.

•• Results found to be very encouraging, Defective coatings Results found to be very encouraging, Defective coatings were identified with high degree of accuracy & repaired.were identified with high degree of accuracy & repaired.

Pipeline Rehab. Coatings Pipeline Rehab. Coatings -- IOCL Experience IOCL Experience

COALTAR ENAMEL COATING (CTE)COALTAR ENAMEL COATING (CTE)

•• Earlier, Coal tar enamel coating was used for inEarlier, Coal tar enamel coating was used for in--situ situ refurbishment of pipeline coating.refurbishment of pipeline coating.

•• However, major limitations are:However, major limitations are:Difficult to maintain the application temperature.Uneven flow of molten CTE resulting in uneven Uneven flow of molten CTE resulting in uneven /inadequate coating thickness particularly at 4/inadequate coating thickness particularly at 4--88’’O clock positionO clock position, Toxic fumes affect the quality of supervision.Health hazard to applicators

Pipeline Rehab. Coatings Pipeline Rehab. Coatings -- IOCL ExperienceIOCL Experience

COALTAR BASED TAPE (CTT):COALTAR BASED TAPE (CTT):

•• Coal Tar Enamel in pliable form & consist of coal tar Coal Tar Enamel in pliable form & consist of coal tar embedded in a fabric reinforcement of fiberglass with a embedded in a fabric reinforcement of fiberglass with a uniform thickness. uniform thickness.

•• Application of CTT is done manually over the primed surface Application of CTT is done manually over the primed surface by slight heating of the inner side of the tape. by slight heating of the inner side of the tape.

•• CTT eliminates few application problems encountered in CTE CTT eliminates few application problems encountered in CTE coating such as coating such as Toxic fumes, Health hazard to applicators etc,

•• Results obtained from the dig sites were not encouraging Results obtained from the dig sites were not encouraging showing defects such as lumping & thinning, holidays, showing defects such as lumping & thinning, holidays, wrinkling etc. wrinkling etc.

Pipeline Rehab. Coatings Pipeline Rehab. Coatings -- COALTAR BASED TAPE COALTAR BASED TAPE


COLD APPLIED TAPE (CAT)COLD APPLIED TAPE (CAT)

CAT is a factory produced Tape having a backing of CAT is a factory produced Tape having a backing of Polyethylene and a Butyl Rubber adhesive layer.Polyethylene and a Butyl Rubber adhesive layer.

No requirement of heating during the applicationNo requirement of heating during the application..

Application using a wrapping machine makes it possible to Application using a wrapping machine makes it possible to achieve correct movement as well as uniform tension.achieve correct movement as well as uniform tension.

Good mechanical properties & uniform coating thickness. Good mechanical properties & uniform coating thickness.

Productivity is highProductivity is high

Least Dependence on human skills Least Dependence on human skills

Environment friendly.Environment friendly.


COLD APPLIED TAPE (CAT) COATING SYSTEM COLD APPLIED TAPE (CAT) COATING SYSTEM ADOPTED IN IOCLADOPTED IN IOCL

Conforming DINConforming DIN--ENEN--12068:199912068:1999Primer Primer –– Liquid Adhesive.Liquid Adhesive.Inner Layer (3ply type)Inner Layer (3ply type)Outer Layer (2ply type)Outer Layer (2ply type)Overlap Overlap –– 50%50%Total Coating Thickness Total Coating Thickness –– 2.5 to 3.0mm2.5 to 3.0mm

Pipeline Rehab. Coatings Pipeline Rehab. Coatings –– Polymer based Polymer based COLD APPLIED TAPECOLD APPLIED TAPE

Pipeline Rehab. Coatings Pipeline Rehab. Coatings -- IOCL ExperienceIOCL ExperiencePolyurethane (PU) coating Polyurethane (PU) coating

Polyurethane coating systems are generally two component airlessPolyurethane coating systems are generally two component airless hot spray applied hot spray applied coatings.coatings.

Nominal thickness of PU maintained between 1000Nominal thickness of PU maintained between 1000--1250microns. 1250microns.

Good mechanical properties & adhesion to the substrate. Good mechanical properties & adhesion to the substrate.

Productivity is high.Productivity is high.

Observations during field application:

Specialized procedure for application and requires trained appliSpecialized procedure for application and requires trained applicators.cators.Close monitoring required to ensure requisite uniform thickness.Close monitoring required to ensure requisite uniform thickness.Proper PPE required during application / inspection due to toxicProper PPE required during application / inspection due to toxic fumes.fumes.Transportation of sophisticated equipment to site.Transportation of sophisticated equipment to site.Surface preparation requirement is high. Coating is less surfaceSurface preparation requirement is high. Coating is less surfaceimperfection tolerant. imperfection tolerant. Insect and dust control till curing is achievedInsect and dust control till curing is achieved..

Pipeline Rehab. Coatings Pipeline Rehab. Coatings –– PU CoatingPU Coating

Pipeline Rehab. Coatings Pipeline Rehab. Coatings -- IOCL ExperienceIOCL ExperienceEpoxy Coating Epoxy Coating

Epoxy coating is pretty much similar to Polyurethane and also inEpoxy coating is pretty much similar to Polyurethane and also involves volves spray application. spray application.

Two pack (Base & Hardener) 100% solid solvent free epoxy was useTwo pack (Base & Hardener) 100% solid solvent free epoxy was used d for trial application.for trial application.

Observations during trial field application:Slow Curing / Dry time, thus resulting in poor productivity rateSlow Curing / Dry time, thus resulting in poor productivity rates.s.Insect and dust control till curing is achieved.Insect and dust control till curing is achieved.Achieving targeted thickness may need multiple coats.Achieving targeted thickness may need multiple coats.Close monitoring required to ensure requisite uniform thickness.Close monitoring required to ensure requisite uniform thickness.Proper PPE required during application / inspection due to toxicProper PPE required during application / inspection due to toxic fumes.fumes.Transportation of sophisticated equipment to site.Transportation of sophisticated equipment to site.Surface preparation requirement is high. Coating is less surfaceSurface preparation requirement is high. Coating is less surfaceimperfection tolerant. imperfection tolerant.

EPOXY COATING

Introduction of Intelligent Pig Survey (IPS)Introduction of Intelligent Pig Survey (IPS)

IPS is a well proven and latest technique for health IPS is a well proven and latest technique for health monitoring of a pipeline and it can scan the complete monitoring of a pipeline and it can scan the complete pipeline.pipeline.

Generally following two types of IPS tool are used :-

1) Ultrasonic Type1) Ultrasonic Type

2) 2) Magnetic Flux Leakage (MFL)Magnetic Flux Leakage (MFL)

a) Longitudinala) Longitudinalb) Transverseb) Transverse

Ultrasonic type:Ultrasonic type:•• This type of survey requires the introduction This type of survey requires the introduction

of a liquid into the pipeline to couple the of a liquid into the pipeline to couple the sensor signal to the pipe wall. sensor signal to the pipe wall.

Magnetic Flux leakage (MFL) type: Magnetic Flux leakage (MFL) type: •• MFL method involves introduction of a MFL method involves introduction of a

magnetic field on the pipe wall and sensing magnetic field on the pipe wall and sensing the leakage of field. Presently MFL technique the leakage of field. Presently MFL technique is the most commonly used technique for is the most commonly used technique for Inline Inspection surveys.Inline Inspection surveys.

Intelligent Pig Survey (IPS)Intelligent Pig Survey (IPS)

•• External and internal corrosion detection and External and internal corrosion detection and subsequent growth monitoring.subsequent growth monitoring.

•• Inspection of pipeline locations which are not Inspection of pipeline locations which are not approachable like river crossing, submerged approachable like river crossing, submerged crossings, bridge crossings etccrossings, bridge crossings etc..

•• To identify corroded section, require replacement or To identify corroded section, require replacement or repair.repair.

•• Setting operational parameters based on pipeline Setting operational parameters based on pipeline health condition.health condition.

•• Assessment of corrosion rate in pipeline by Assessment of corrosion rate in pipeline by comparing data of previous survey.comparing data of previous survey.

•• Planning for operation and maintenance activities.Planning for operation and maintenance activities.

REQUIREMENT OF INTELLIGENT PIG SURVEYREQUIREMENT OF INTELLIGENT PIG SURVEY

•• MFL tool is housed with Permanent magnets with MFL tool is housed with Permanent magnets with sensors & secondary sensors.sensors & secondary sensors.

•• Magnetically Saturate Magnetically Saturate PipewallPipewall ,One Small part at a ,One Small part at a time. time.

•• Magnetic flux tends to travel through steel and Magnetic flux tends to travel through steel and magnetic saturation occurs. magnetic saturation occurs.

•• Once the steel becomes saturated some of the flux Once the steel becomes saturated some of the flux starts to significantly leak out of the material.starts to significantly leak out of the material.

•• Localized decrease in pipe wall thickness (Localized decrease in pipe wall thickness (i.e. i.e. corrosion) causes a localized increase in magnetic corrosion) causes a localized increase in magnetic saturation that in turn causes localized increases in saturation that in turn causes localized increases in flux leakage.flux leakage.

BASIC PRINCIPLE OF MFL TECHNIQUEBASIC PRINCIPLE OF MFL TECHNIQUE

•• Sensors housed in tool measures the flux leakages Sensors housed in tool measures the flux leakages caused by metal loss or by other anomalies.caused by metal loss or by other anomalies.Primary sensorsPrimary sensors measure the flux leakage in the measure the flux leakage in the internal or external pipe surface.internal or external pipe surface.Secondary sensorsSecondary sensors will measure the flux leakage will measure the flux leakage caused by metal loss in the internal surface.caused by metal loss in the internal surface.

•• Flux leakages are measured and interpolated in Flux leakages are measured and interpolated in order to measure and characterize the defect.order to measure and characterize the defect.

•• Sensors detect the flux leakage and various Sensors detect the flux leakage and various techniques are used to analyses the signals. techniques are used to analyses the signals.

•• The defects are characterized on the basis of type, The defects are characterized on the basis of type, size, shape, orientation and locationsize, shape, orientation and location

BASIC PRINCIPLE OF MFL TECHNIQUEBASIC PRINCIPLE OF MFL TECHNIQUE

•• CLEANING PIGSCLEANING PIGS:: PIG is launched to clean the PIG is launched to clean the pipeline from muck/debris, which may be pipeline from muck/debris, which may be present in the pipeline.present in the pipeline.

•• GAUGING PIGGAUGING PIG:: Gauging PIG equipped with Al Gauging PIG equipped with Al plates is launched to check the internal plates is launched to check the internal geometry of the pipeline. Results are analyzed geometry of the pipeline. Results are analyzed based on physical condition of Al. plates. If based on physical condition of Al. plates. If deformations is large (more than 10%), deformations is large (more than 10%), rectification/rerectification/re--run may be planned. run may be planned.

SEQUENCE OF INTELLIGENT PIG SURVEYSEQUENCE OF INTELLIGENT PIG SURVEY

before run after run

14”GAUGE PIG BEFORE AND AFTER RUN

•• MARKER MAGNETSMARKER MAGNETS:: Before the caliper PIG run, Before the caliper PIG run, marker magnets are installed all along the pipelines at marker magnets are installed all along the pipelines at every 1every 1--2 2 kmskms of interval.of interval.

•• CALIPER PIGCALIPER PIG:: to determine bends and their bending to determine bends and their bending direction Electronic Geometric Pig is launched. The direction Electronic Geometric Pig is launched. The EGP results will clearly show if any restrictions are in EGP results will clearly show if any restrictions are in the pipeline that might prevent safe passage of the ILI the pipeline that might prevent safe passage of the ILI tool. tool.

•• The geometry run will also give detailed information The geometry run will also give detailed information on geometrical features, such as bends, on geometrical features, such as bends, ovalitiesovalities. . Dents etc. Rectification of deformation if any which Dents etc. Rectification of deformation if any which may restrict passage of intelligent pigmay restrict passage of intelligent pig


•• PULL THROUGH TEST : PULL THROUGH TEST : Before the launch of ILI tool in Before the launch of ILI tool in the pipeline the tool undergoes pull through test, the pipeline the tool undergoes pull through test, wherein the tool is passed through a section of pipeline wherein the tool is passed through a section of pipeline with known defects at contractor works. with known defects at contractor works.

•• WET LOOP TEST: WET LOOP TEST: Generally, during initial development Generally, during initial development stage, ILI tool is also tested in wet loop. stage, ILI tool is also tested in wet loop. The purpose of this test is to ascertain the accuracy of The purpose of this test is to ascertain the accuracy of the tool in terms of detection of defects.the tool in terms of detection of defects.

•• IP SURVEY:IP SURVEY: Once the IP tool successfully passes pull Once the IP tool successfully passes pull through test, the tool is introduced in the pipeline and through test, the tool is introduced in the pipeline and data is collected.data is collected.


GENERAL VIEW AND FUNCTIONINGGENERAL VIEW AND FUNCTIONING

MFL INTELLIGENT PIG – SENSOR.

ONLINE DATA PROCESSINGONLINE DATA PROCESSING

Detect following with size and Detect following with size and chainagechainage of pipeline.of pipeline.

Internal corrosion. Internal corrosion.

External corrosion.External corrosion.

All fitting in pipeline like valves, All fitting in pipeline like valves, sleevessleeves, leak clamps etc. , leak clamps etc. And girth weldAnd girth weld

Length of each pipes with thickness details.Length of each pipes with thickness details.

Longitudinal and circumferential grooving.Longitudinal and circumferential grooving.

Type of defectType of defect

Associated with software to prioritize the defects for Associated with software to prioritize the defects for repair and to assess the overall health condition of the repair and to assess the overall health condition of the pipelinepipeline..

MINIMUM REQUIREMENT OF INTELLIGENT PIG MINIMUM REQUIREMENT OF INTELLIGENT PIG

CLASSIFICATION OF DEFECTSCLASSIFICATION OF DEFECTS

RELEVANCE OF IPS WITH OPERATIONRELEVANCE OF IPS WITH OPERATION

•• IPS REPORT IS BASE FOR THE ASSESSMENT OF LINE IPS REPORT IS BASE FOR THE ASSESSMENT OF LINE CONDITION AND MAOP FOR THE LINE IS SET CONDITION AND MAOP FOR THE LINE IS SET ACCORDINGLY.ACCORDINGLY.

•• BEFORE START OF SURVEY DETAILS OF LINE WITH EXISTING BEFORE START OF SURVEY DETAILS OF LINE WITH EXISTING MAOP ARE GIVEN TO THE SURVEYOR.MAOP ARE GIVEN TO THE SURVEYOR.

•• LINE DETAILS ARE REQUIRED TO FIX TOOL PARAMETERS LINE DETAILS ARE REQUIRED TO FIX TOOL PARAMETERS AND EVALUATION OF IPS RESULTS.AND EVALUATION OF IPS RESULTS.

•• EXISTING MAOP IS REQUIRED TO EVALUATE SEVERITY OF EXISTING MAOP IS REQUIRED TO EVALUATE SEVERITY OF FEATURES AND CALCULATION OF ERF VALUE.FEATURES AND CALCULATION OF ERF VALUE.

DETERMINATION OF ESTIMATED REPAIR DETERMINATION OF ESTIMATED REPAIR FACTOR (ERF)FACTOR (ERF)

•• ERF is calculated to classify the defects on the basis of ERF is calculated to classify the defects on the basis of severity. ERF is the ratio of true MAOP of the pipeline to severity. ERF is the ratio of true MAOP of the pipeline to the calculated MAOP in corroded area of the defect.the calculated MAOP in corroded area of the defect.

ERF = MAOP/MAOP in corroded area (pERF = MAOP/MAOP in corroded area (p’’))

LIMITATION OF IPS– No direct assessment of pipe Strength (only

metal loss detected).– Difficult to idenfify the Weld defect/material

defect.(Hydrotest would be required for finalization of safe operating pressure of pipeline).

– MFL is indirect measurement of wall loss, any error in data interpretation would lead to error in final data.

– More depended on data interpreter

TYPICAL PLOT – RESULTS OF IPS (FEATURE DENSITY)

TYPICAL PLOT - RESULTS OF CAT SURVEY

0

10

20

30

40

50

60

70

80

90

0 2 4 6 8 10 12 14 16 18 20Pipeline Chainage

dB L

oss / K

M

IPS RESULT Vs COATING SURVEY

MAINLINE MAINTENANCE

Strainer

HSD

SK

ATF

MS

SRBFrom Panipat

Pump Station layout

MP-3 MP-2 MP-1

To Jalandhar

SLB

EH

TM

TM

EH

S/F

TM TM

14” 14”MOV

14”MOV

8” 3”

12”

12” MOV

12”

12”12” 6”

6” 6”

6”

6” 6”

6” 6”

14” MOV

10”

10”

10”

10”

14” 14”

14”

14”

10” 10”

14”

12” 12” MOV

12”

12” MOV12” MOV

8” 8” 8”

8”

12” 12”

12”MOV8”

2”

12”MOV 12”IC

IFD 12”

IC

INSPECTION OF R.O.W.• To observe surface condition

Wash outsLeaksEncroachments

• To inspect the Markers & accessoriesMarkersTLPsBlock ValvesCP / RCP stations

• To inspect Crossings & vulnerable locations and special attention to suspended crossings, exposed area etc.

MAINLINE FACILITIES

• Boundary Pillar (BP)

• Turning Post (TP)

• Kilo Meter Post (KMP)

• Vent Pipe (VP)

• Test Lead Post (TLP)

• Caution Board

• Block Valve (BV)

• CP Station

•Repeater Station

•Repeater cum CP Station (RCP)

MAINLINE LAYOUTPosition of M/L markers

IOCLKBPL

IOCL

KBPL

IOCL

KBPL

IOCL

KBPL

154RO

AD

VP

BP

KMPTP

TLPVP

Casing PipeCaution Board

MAINLINE PATROLLING

• Daily Patrolling by Line Patrol Man (LPM)

• Surprise check by officers

• Mainline Patrolling by officers

• Daily Patrolling Report

• Monthly Patrolling Report

• Surprise Check Report

• Report on M/L Inspection by officers

ROW MAINTENANCE

• Providing missing M/L markers

• Painting of existing M/L markers

• Updation of Caution Boards

• Removal of bushes, trees etc from ROW

• Attending washouts

• Removal of encroachments

• Attending shorted cased crossing

• Refurbishing of Coat & Wrap

MAINLINE EMERGENCIES

• Leak

• Burst

• Pilferage

• Welding of Leak Clamp

• Welding of Sleeve (Full/Half)

CORROSION INHIBITOR

••AN INHIBITOR IS A SUBSTANCE, WHEN ADDED IN AN INHIBITOR IS A SUBSTANCE, WHEN ADDED IN SMALL CONCENTRATION TO AN ENVIRONMENT SMALL CONCENTRATION TO AN ENVIRONMENT DECREASES THE CORROSION RATE.DECREASES THE CORROSION RATE.

••MOST INHIBITORS HAVE BEEN DEVELOPED BY MOST INHIBITORS HAVE BEEN DEVELOPED BY EMPIRICAL EXPERIMENTATION.EMPIRICAL EXPERIMENTATION.

••MANY INHIBITORS ARE PROPERIETARY IN NATURE MANY INHIBITORS ARE PROPERIETARY IN NATURE AND THEIR COMPOSITION IS NOT DISCLOSED.AND THEIR COMPOSITION IS NOT DISCLOSED.

CORROSION INHIBITOR

• IN CROSS-COUNTRY PRODUCT PIPELINE, WE ARE USING CORROSION INHIBITOR TO MITIGATE THE INTERNAL CORROSION OF PIPELINE.

•PRESENTLY UNICOR-J @ 6PPM IS BEING USED.

•CORROSION INHIBITOR FORMS A LAYER INSIDE THE PIPE AND MAKE IT PASSIVE.

•IN CRUDE PIPELINE, NO C.I. IS INJECTED IN IOCL PIPELINE•BH CRUDE FORMS A LAYER OF WAX.

CORROSION PROBES & COUPONS

INTERNAL CORROSION RATE OF PIPELINE IS BEING MONITORED BY :-

1) CORROSION COUPON :- INSTALLED AT NRVs/AT SUITABLE LOCATIONS.

2) CORROSION PROBES:- INSTALLED IN MAINLINE & WORKING ON RESISTANCE MEASUREMENT.

INTERNAL CORROSION RATE

Category Average corrosion rate ( MPY)

Low < 1.0

Moderate 1.0 – 4.9

High 5 – 10.0

Severe > 10.0

As per NACE RP-0775-91 corrosion rate is categorized as

ER PROBE:

No. Description Material

1 Protective Cover Carbon Steel

2 Extension Adopter 316SS

3 ‘O’ Ring for Cover Viton

4 Hollow Plug Assy 316 SS

5 Primary Packing Teflon

6 screw Lock 316SS

8 Flush ER Probe 316 SS

INTERNAL CLEANING OF PIPE

• Pigging operationTypes of Pig: Cleaning Pig, Batching Pig,

Caliper Pig,Foam Pig, Instrument Pig

• Purpose of pigging:1. To clean the new pipe debris. 2. To know the inside pipe dia profile. 3. For inspection and measurement of any

corrosion or metal loss.4. For generating initial pipe line data.

• Mandrel pigs, which have a central body tube, or mandrel, and various components which can be assembled onto the mandrel to configure a pig for a specific duty;

PIGGING AND ITS IMPORTANCE

• Scrapper pigs, which have a central body tube, or mandrel, and various components like PU cups and spring steel brushes which can be assembled onto the mandrel to configure a pig for a specific duty.


• BI-DI or Batching pigs, which have a central body tube and disc components can be assembled onto the body to configure a pig for a specific duty;


Experience of IOCL

Case Study

• Product Pipeline in operation since 1966

(API 5L X-46 ERW)

• Few corrosion failures occurred.

• Pipeline was de-rated to 80% of the MAOP

• In line inspection of the pipeline was

carried out.

Experience of IOCL Case Study (cont..)Case Study (cont..)

•• Critical defects in the pipeline were Critical defects in the pipeline were rectified.rectified.

•• To check the seam integrity, hydroTo check the seam integrity, hydro--test test was conducted.was conducted.

•• Result of Result of hyrotesthyrotest was quite encouraging.was quite encouraging.

•• 7 significant defects were eliminated. 7 significant defects were eliminated.

Experience of IOCL Case Study Case Study ––2 (cont..)2 (cont..)

•• CAT, DCVG & CPL Survey conducted to check the CAT, DCVG & CPL Survey conducted to check the performance of existing CP & coating.performance of existing CP & coating.

•• Pipeline metal loss features identified by IPS were Pipeline metal loss features identified by IPS were plotted with the results of CAT/DCVG/CPL & plotted with the results of CAT/DCVG/CPL & based on result, priority made for coating based on result, priority made for coating refurbishment & job executed.refurbishment & job executed.

Experience of IOCL Case Study (cont..)Case Study (cont..)

•• Results found to be very encouraging, Defective Results found to be very encouraging, Defective coatings were identified high degree of accuracy & coatings were identified high degree of accuracy & repairedrepaired

•• CP system was upgraded by providing solar CP system was upgraded by providing solar battery bank/battery bank & renovation of ground battery bank/battery bank & renovation of ground bedsbeds

•• Appreciable improvement in line protection Appreciable improvement in line protection achieved. Current density reduced up to 50%.achieved. Current density reduced up to 50%.

•• No corrosion failure in last 5 years.No corrosion failure in last 5 years.

•• Pipeline was rePipeline was re--rated to new MAOPrated to new MAOP

HYDROSTATIC TESTING OF

P-M & M-A SECTIONS OF BKPL

DETAILS OF LINE FAILURES OCCURRED FURING HYDROTESTING

BK/HYDRO

STAGES OF PRESSURE TESTING

NO. OF FAILURE

FAILURE NOS.

SEAM FAILURE LENGTH/ WIDTH

FAILURE PRESSURE

(EX-ALD) IN KG/CM2

IST STAGE 1 IST 1.4 MTR/ 8MM

49.5

2ND STAGE 4 2ND 2.1 MTR./11 MM

63.0

35D 0.11 MTR/4MM

61.5

4TH 0.1 MTR/1 MM

75.0

5TH 1.0 MTR/10 MM

75.0

3RD STAGE 2 6TH 2.1 MTR/22 MM

82.0

7TH 0.04 MTR 85.0

iii sinha iocl

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