Post on 28-Dec-2015
Development Indigenous instrumented Pig – A Success
Story
Overview of Presentation
Introduction
Development of Instrumented Pig
Development of Testing Infrastructure
Evaluation of IPIG in Wet test loop and pipelines
Lesson Learning and successful development
Inspection of Pipelines
Conclusions
Introduction
Above 40,000 km pipeline network is existing in India to transport
petroleum products, crude oils and natural gas
It is Immensely important to maintain the pipelines in healthy
condition for safe operation over a long period
Pipelines are protected by using good quality coatings to avoid direct
contact with surrounding soil supplemented by CP system to protect
from corrosion
Pipelines are also Inspected using inline inspection tools, popularly
known as instrumented pig (IPIG), to monitor their health
Instrumented Pigs
Widely used for inline inspection of cross country pipelines for
monitoring their health.
IPIG travels through pipeline with the propelling force of the
fluid being transported
After the inspection run, data is downloaded and interpreted
using the closely guarded data analysis software package
Analysis provides information of all pipeline features such as
valves, fittings, weld and metal loss with fairly good level of
defect sizing and within ± 1 to 5 meter of locational accuracy
Indigenous Development
IndianOil-R&D, in association with BARC, developed MFL based
Instrumented Pig Technology for the first time in the country.
Extensive research work carried out in designing, development of
components, modules and integrated tools and evaluation facilities
Exhaustive evaluations of IPIG for negotiability, endurance, wear and tear,
shock, vibration and data acquisition capability
Instrumented Pigs of 12” & 14” size commercialized. Development of
18” & 24” IPIG completed and is under testing and evaluation.
Technology and tools for inspection of other sizes and applications are
planned for development.
12” Instrumented Pig
12” Caliper Pig (CPIG)
14” Instrumented Pig (IPIG)
24” Caliper pig (CPIG)
24” Instrumented pig (IPIG)
P
P
P
N S
Basic Principle of operation of IPIG
Hall Sensor
Pipeline Wall Thickness
External Metal LossMagnetic flux lines
Strong permanent magnets (NdFeB) are used to magnetize the pipe wall
Magnetic flux leaks due to: • Presence of metal loss on the pipe
wall.• Existence of extra ferrous material
near the pipe wall.• Any change in properties of the pipe
wall material Primary sensors and secondary sensors
sense magnetic flux leakage. Secondary sensors detect internal defects
Specification of Indigenous IPIGs
Sr. No Description Remarks
1. Axial sampling (mm) 2.32 mm (changeable w.r.t. flow rate)
2. Continuous recording 350km
3. Primary & Secondary sensors (Nos.) 72 & 56 for 12” and 84 & 72 for 14”
4. Odometers 3 Nos.
5. Location accuracy (meters from nearest marker) 0.1%
6. Minimum detectable defect (Length X Width X %WL) 2t X 2t X 10% TH, t = 6mm
7. Confidence of detection (% of total defects) 90
8. Confidence of characterization (% of detected defects) 90
9. Confidence of differentiating internal and external defects (% of detected defects)
80
10. Minimum detectable defect in thicker pipe 3t X 3t X 20% TH, t = 9, 12 mm
11. Minimum pipe bend (radius) 5D, D = Nom. Dia.
Defect Sizing and Location Accuracy
Types of metal loss Definition
Minimum Sizing
Accuracy
Depth Sizing
Accuracy
Length Sizing
Accuracy
Width Sizing
Accuracy
Pitting Corrosion < 3tx3t +0.15t +0.15t +12mm + 12mm
General Corrosion > 3tx3t +0.1t +0.10t +15mm + 20mm
Axial Grooving +0.20t +0.20t +15mm + 12mm
Circum. Grooving + 0.15t +0.15t ±12mm + 20mm
Locational and Orientation Accuracy
Axial position accuracy from reference marker 1:1000 mts.
Circumferential position accuracy ±150
Evaluation facilities
Need of Evaluation Facilities
Development of inspection technology
To generate design data for components
To carry out functional tests on mechanical and electronic components
Carrying out Pre and Post inspection activities
Functional check
Data check
Data completeness
Data quality etc.
Validation to qualify for inspection
Verification of results obtained from testing based on full scale data bank
Continuous improvement in capabilities of tools
Evaluation Infrastructure
Facilities to generate design data :
Static rig
Rotary rig
Facilities to evaluate functional checks such as negotiability,
endurance & data acquisition capability:
Linear Pull through rig
Hydrostatic testing rig
Wet test loops of various sizes
Static Test Rig
Purpose: Designed to study MFL levels around a
test section made of pipe material of dimension of 320 mm (length) x 125 mm (width).
Details: One sub-assembly of magnetic module
consisting of backing iron, brushes, test section and two NdFeB magnets are fixed on the table.
Hall sensors are used to detect the leakage flux.
The entire area over the test section is scanned and deformity data is captured.
Rotary Test Rig
Purpose: Rotary test rig is used to study the
effect of velocity on metal defect signal in the laboratory.
Dynamic testing of sensors and its repeatability can also be checked.
Details: The 28” drum is rotated on four
wheels. The speed of drum can be changed.
Two sub-assembly of magnetic module having four sensor modules in each, is placed on the drum.
The data is acquired Defects of different sizes are made
to generate databank.
Linear Pull - Through Rig
Purpose: Dry evaluation of mechanical
components and module of prototype IPIG
Generation of database for defect characterization (studying the electronics and data acquisition system)
Details: The rig consists of 25 mtrs. length of
actual field pipelines. A semi cylindrical SS launching/
retrieving trays are connected to a reducer at either end of the rig to retrieve the pig.
A motor drive gearbox assembly winches the pig through the linear pull through rig with the help of a wire rope.
12” Wet Test Loop
Purpose :Proving mechanical negotiability of various types of PIGs, through pipe fittings Mechanical endurance testing on mechanical componentsGenerating signatures of various pipe fittings and metal loss defects under simulated field pipeline conditionDetails:Length -120mFlow rate 0 – 200m3/h5D and 6D bends
When PIG passes PS1Valves V1, V3 & V2 openedValves V4, V6 & V5 closed
When PIG passes PS2Valves V4, V6 & V5 openedValves V1, V3 & V2 closed
12” Wet Test Loop – Flow Scheme
24” Wet Test Loop
Purpose:Proving mechanical negotiability through pipe fittings Endurance testing on mechanical componentsGenerating signatures of various pipe fittings and metal loss defects under simulated field pipeline conditionDetails:Length - 444mFlow rate 0 – 2400m3/h5D bends
Spools for Negotiability
311-275-311
12 mm Protrusion
Pipe Spool with External defects
Defect Creation Machine
Creation of defects on 12”, 14”, 18” and 24” pipes
Defect on external surface of any size and shape
Hydro Test Facility
Purpose For pressure testing
of Data Acquisition system and other modules
Details: Length – 3m Sizes and thickness
of vessel – 24” (OD) x 0.375”(WT)
Max. test pressure – 100kg/cm2
Evaluation in Wet Test Loop and Actual
Pipelines
Gauge Pig Run
Improvements in Compressibility of Magnetic module Development of 12” IPIG
Gauge plate launched in Pipeline section with geometry of 12” pipelines: OD: 324mm ID: 311mm (for 6mm WT) ID: 298 mm (for 12mm WT)
Gauge Plates Size275mm, 280mm, 285mm
Plate received like Saucer shapeProject abandoned and magnetic module was redesigned
Gauge Pig Run in WTL
Gauge Pig Run – Run in HM section
Gauge Pig Run – Run in DP section
Mechanical Negotiability
Mechanical Components Such as:
Poly Urethane Cups
Brushes
Sensor Mounting arms
Odometer wheels
Tow Links
Endurance Testing to Check Wear and tear
Success after Few Failures in Wet test loop
and Pipeline runs
Evaluation of IPIG with Dummy Sensors
Evaluation of IPIG in WTL
Dummy IPIG fitted with PU cups tested
in Wet Test Loop for ascertaining
behavior of cups, sealing and wear &
tear.
Based on testing, performance
specifications of PU cups drawn.
During initial trial runs, wear & tear of
cups was excessive.
Material properties like type of
material, hardness, tear resistance,
abrasion loss etc improved.
Improvements in Mechanical components – PU Cups
Side View of Retrieved IPIG (after wash) showing damage to Cups
PU Cups of IPIG (During evaluation in AB section)
Initially, potted wire brush were
used for directing the magnetic
field to the pip wall.
Performance of Wire brush was
studied in Wet Test Loop and field
pipelines.
Poor negotiability was observed at
weld protrusions, bends and heavy
wall thick pipe regions.
Material properties like type of
material, hardness, tear resistance,
etc improved.
Improvements in Mechanical components – Wire Brush
Brushes after Testing (During Evaluation in MA section)
Brushes and Primary Sensor Arms(During evaluation in MA section)
PIG locator Module(Failure of Tow Link and PU CUP)
IPIG stuck at the Insulating flange (During Evaluation in MA section)
IPIG stuck at the Insulating flange (During Evaluation in MA section)
IPIG stuck at the Insulating flange (During Evaluation in MA section)
IPIG stuck at the Insulating flange (During Evaluation in MA section)
Close up of IPIG front after Close up of IPIG front after dismantling of scrapper Barrel.dismantling of scrapper Barrel.
Retrieval of IPIG Tool with help of Retrieval of IPIG Tool with help of Chain Pulley BlockChain Pulley Block
Retrieval of IPIG (During evaluation in AB section)
Swiveling action at odometer base was
removed
Odometers of large wheel diameter were
employed to reduce slippage Mounting of odometer assembly at the rear of pig
locator module to avoid fouling/ obstruction
Employing double sided support arm for odometer
wheel to have better stability and strength Adopting different method of sensing distance by
employing inductive type proximity switch (better
sensing, less muck deposition so less tendency to
jamming)
Improvements in Mechanical components - Odometers
Uniformity in spacing between sensors
Mounting of sensor assembly on SS
mounting ring between centre of backing
iron assembly employed to achieve full
periphery coverage
Non magnetic high spring steel sensor
mounting plate used to have 100%
contact with pipe wall
Sensor wear plate modified to
withstand high wear
Improvements in Mechanical components –Primary Sensor Assembly
First generation single board computer based DAS –
Pentium based CPU card with 16 channel data acquisition
card, multiplexer & flash disk
Second generation Digital Signal Processing (DSP)
system with 02 nos. DSP processor based 80 channel data
acquisition card for data storage & Flash disk for storage
Third generation Microcontroller based data
acquisition card with on board storage on flash chips(ICs) &
flange mounted cards for cleaner interconnections and to put
DAS and battery in a single module reducing IPIG to 3
modules pigable distance ~400kms
Developments in Electronics
Comparison of Results (Static, LPT Rig & WTL)
Notch Size, mm
Radial F. D. P-P Gauss - SR
Radial F. D. P-P Gauss - LPT
Radial F,. D. P-P Gauss - WTL
Span(mm)
18 x 18 x 2 230 128 67 18/24/18
18 x 18 x 3 235 176 - 18/20/-
18 x 18 x 4 - - 119 16
24 x 24 x 2 235 176 104 24/45/28
24 x 24 x 3 295 224 - 24/45/-
24 x 24 x 4 - 496 173 -/26/22
24 x 24 x 5 - 576 - -/26/-
Summary of Field Trial Runs
Sr. No. Date Summary/modifications carried out after field trial
1. Sept. – Oct’
2000
Switch over to time sampling in case all the odometers fail to work
Tow-links, cups strengthened
2. 1st week
Jun’ 01
No damage to tow – links and PU cups
1.6 GB data acquired
Sensor shorted causing power supply to trip
Irregular odometer pulses
3. 2nd week of
Jun’ 01
3.7 GB data acquired for 47 kms
Sensor shorting due to sensor wear
Stuck at Allahabad pump station on weld protrusion at isolation
flange. Magnetic brushes re-engineered
Fuses provided to sensors to prevent trip of power supply due to
sensor shorting
Sr. No. Date Summary/modifications carried out after field trial
4. Feb –
Mar’ 02
IPIG was launched and retrieved without mechanical
damage. No data acquired.
DAS failed to record due to excessive vibrations.
New Hard Disk mounting designed
5. Sept –
Oct’ 02
No data acquired. No mechanical damage to IPIG.
Hard disk is vulnerable to failure during vibration
Hard disk was replaced by Flash Disk and operating
system was housed in Disk-on-Chip.
6. Jun’ 03 4GB data was acquired in 74.6 kms
IPIG was retrieved without mechanical damage
Odometers improved after inconsistence performance.
Summary of Field Trial Runs
Sr. No. Date Summary/modifications carried out after field trial
7. Jun’ 04 No mechanical damage to IPIG modules
IPIG acquired 8 GB data
8. Dec’ 04 Consistent performance of all the three odometers
observed.
IPIG acquired approximately 8 GB data during the run
of 54.5 hrs and a travel of 140.2 kms approximately.
9. Jun’ 05 IPIG acquired 10GB data.
All odometers rotating freely.
The performance of IPIG run was satisfactory.
03 nos. of defects verified through dig site.
Summary of Field Trial Runs
S. No. Section (km) Date of Inspection
1 Mugalsarai – Allahabad (147) December 2004
2 Patna – Mugalsarai (152) March 2006
3 Barauni – Patna (103) November 2007
4 Asansol – Barauni (100) April 2008
5 Mourigram – Rajbandh (110) 14th February 2009
6 Allahabad – Kanpur (196)8th-11th December
009
TOTAL = 808km
Inspection runs of 12” IPIG
S. No. Section (km) Date of Inspection
1 Patna-Mugalsarai (210) Nov’2006
2 Barauni-Patna (103) Nov’2007
3 Haldia-Mourigram (118) Feb’2009
TOTAL = 431km
Inspection Runs of 12” CPIG (2006-10)
MFL Signatures acquired by IPIG
General Features & Installations
Field Pipeline Wet Test Loop
Markers Markers
Welds Welds
Flanges Flanges
Area Starts Raised section
Area Ends Raised section
Supports Supports
Sleeves --
Clamps --
Taps --
Tees Tees
Attachments Attachments
Valves Valves
Metal Loss Metal Loss
Marker MFL Signature
Weld MFL Signature
Weld
Flange MFL signature
Valve MFL signature
Valve
Area End with weld
Weld
Area Start with weld
Weld
FlangeFlange
Sleeve MFL Signature
Sleeve Start
Sleeve End
Attachment MFL Signature
Area Start MFL Signature
Area Start of Bend
Area End MFL Signature
Area End of Bend
External Metal Loss
External Metal Loss
Results and Discussions
(Digsite Verification of Metal Loss defects)
Dig-site Verification
Tool validation is carried out by carrying out dig-site
verifications
Common method for evaluating in-line inspection results NACE Standard RP0102
API Standard 1163
Results of dig-site verifications confirms the capability of
tool and these results are also used for continuously
refining the data analysis procedures
Emphasis is given on physical dig-site verification and
taking measurements.
Defect Dimension Classification
Source: Specification & requirements for intelligent pig inspection of pipeline, Version 3.2, January 2005
A = Wall thickness or 10 mm (0.39”) whichever is greater
Basic Procedure(Verification Measurements)
1. Length and width of defect measured using Vernier scale of least count 0.02 mm
2. Depth (%WL) of defect measured using pit gauge of least count 0.1mm
3. O’clock position of defect is measured by eye estimation
4. Defect distance from nearest weld is measured using tape.
Conformable Eddy Current ArrayInspection system
Basic Procedure Corrosion depth adjustment
Depth adjustment for defects with background corrosion
Chainage (m)
Reported Actual
Length
(mm)
Width
(mm)
%
WL
Clock Length
(mm)
Width
(mm)
%
WL
Clock
73328.5 18 31 35 5:05 38 36 35 5:00
7334.87 9 20 42 5:25 9 18 40 5:30
130706.2 13 18 45 7:40 14 14 42 7:45
One mismatch in length observed
Digsite Verification (M-A section)
Defects Between Sleeves (Additional verification)
• A severe defect detected between sleeves at 73223.48m from Mughalsarai pump station.
• Defect: Length: 22 mmWidth: 20 mm%WL : 77% O’clock: 6:45
Metal Loss
1st Sleeve End 2nd Sleeve Start
2nd Sleeve End
1st Sleeve Start
Digsite Verification (M-A section)
FEATURE AT:130706.15 m
MM64 at 130178.22 527.93 1475.99 MM65 at 132182.14
10.70 11.42 11.10 2.85 9.16 11.39 11.25 11.36
11.1 2.9 9.14 11.4upstream downstreamLength 13.00 14.00 Width 18.00 14.00 %WL 44.00 41.7
Position 7:40 7:45
Note: Measured quantities are are indicated in colour.1. Figures in blue are pipe lengths measured by tape.2. Figures in green are defect dimensions measured by vernier scale.3. Figure in red is % depth of defect measured by pit gauge.4. Figure in orange is is an eye estimate of the o'clock position of defect.5. Very acurate log distance could not be acertained.
14
14
20 deg2.5
FEATURE AT:73334.33 m
MM36 at 73150.43 183.90 1814.75 MM37 at 75149.08
11.48 10.85 11.22 5.41 5.10 10.71 11.72 10.89
11.25 5.61 4.94 10.45upstream downstream
Length 9.00 9.00 Width 20.00 18.00 %WL 42.00 40.00
Position 5:25 5:30
Note: Measured quantities are indicated in colour.1. Figures in blue are pipe lengths measured by tape.2. Figures in green are defect dimensions measured by vernier scale.3. Figure in yellow is % depth of defect measured by pit gauge.4. Figure in red is is an eye estimate of the o'clock position of defect.5. Very acurate log distance could not be acertained.
80 degree
2.3718.00
9.00
Corroded pipe surface
Digsite Verification (M-A section)
Corroded pipe surface
Chainage (m)
Reported Actual
Length(mm)
Width(mm)
%WL
Clock Length(mm)
Width(mm)
%WL
Clock
120.07(u/s MM 308)
27 43 49 6:00 40 42 34 05:40
121.83(u/s MM 308)
22 35 47 4:05 20 50 32 3:30
202.94(u/s MM 312)
23 42 54 7:30 28 42 47 8:00
203.75(u/s MM 312)
25 39 58 7:30 25 38 42 7:55
Results within the tolerance limits
Dig-site Verification (P-M section)
Type of data Reported Max. value of parameter
Desired Accuracy
Distance from U/S girth weld
5.362 m 5.362 m
Distance from D/S girth weld
3.826 m 3.826 m
External / Internal External External
Length 31 mm 57 mm ±15 mm
Width 51 mm 136 mm ±15 mm
Depth 81% (5.14 mm)
68.3%(4.34 mm)
±10%
O’clock 11:15 10:00 - 12:00 ± 150 (30 min)
Remarks: The data in respect of depth, length and o’clock position are within the accepted limits. However there is variation in width
Defect at Ch. 175604.8m
Dig-site Verification (A-K section)
Type of data Reported Max. value of parameter
Desired Accuracy
Distance from U/S girth weld
5.156 m 5.156 m
Distance from D/S girth weld
4.032 m 4.032 m
External / Internal
External External
Length 31 mm 57 mm ±15 mm
Width 47 mm 47 mm ±15 mm
Depth 57% (3.62 mm)
64.09 %(4.07 mm)
±10%
O’clock 10:30 10:00 ± 150 (30 min)
Remarks: The data in respect of depth, width and o’clock position are within the accepted limits. However there is variation in length.
Defect at Ch. 175604.5m
Dig-site Verification (A-K section)
Type of data Reported Max. value of parameter
Desired Accuracy
Distance from U/S girth weld
4.532 m 4.532 m
Distance from D/S girth weld
4.656 m 4.656 m
External/ Internal
External External
Length 50 mm 50 mm ±15 mm
Width 47 mm 80 mm ±15 mm
Depth 54% (3.43 mm)
44.33%(2.81 mm)
±10%
O’clock 10:52 10:00 - 11:00 ± 150 (30 min)
Remarks: The data in respect of depth, length are within the accepted limits. However, there is variation in width
Defect at Ch. 175603.9m
Dig-site Verification (A-K section)
Dig-site Verification (D-P section)
Critical defect above 80% wall thickness loss reported at ch 5343.441m between major road crossing.
However, the metal loss was not observed during the dig-site verification.
The error in prediction was attributed to the sub surface defect and the pipeline was protected by providing sleeve.
Type of data Reported Max. value of parameter
Desired Accuracy
Distance from U/S girth weld
5.037 m 5.003 m
Distance from D/S girth weld
6.167 m 6.200 m
External / Internal External External
Length 15 mm 16.5 mm ±15 mm
Width 34 mm 32 mm ±15 mm
Depth 32% (2.28 mm)
29 % ±10%
O’clock 10:20 06:50 ± 150 (30 min)
Remarks: The data in respect of depth, width & length are within the accepted limits. However, there is variation in o’clock position
Defect at Ch. 3676.081m
Dig-site Verification (D-P section)
Type of data Reported Max. value of parameter
Desired Accuracy
Distance from U/S girth weld
11.012 m 11.140 m
Distance from D/S girth weld
0.411 m 0.410 m
External / Internal External External
Length 15 mm 22 mm ±15 mm
Width 44 mm 100 mm ±15 mm
Depth 37% (2.642 mm)
21.33 % ±10%
O’clock 04:43 01:00 - 02:00 ± 150 (30 min)
Remarks: The data in respect of depth & length are within the accepted limits. However there is variation in width and o’clock position
Defect at Ch. 6229.40m
Dig-site Verification (D-P section)
Activity completed and major pilferage point at 37.580 km from Bijwasan has been identified & located.
Dig-site Verification (D-P section)Pilferage located by 14” IPIG in 2008
Activity completed and major pilferage point at 16.65 km from Bijwasan has been identified & located.
Dig-site Verification (D-P section)Pilferage located by 14” IPIG in 2009
Dig-site Verification (D-P section)Pilferage located by 14” IPIG in 20.05.2010
A major pilferage point at 94.40km from Bijwasan has been identified
Dig-site Verification (D-P section)
Critical defect above 57% wall thickness loss reported at ch 98623m.
However, mill defect was (44-48%) observed during the dig-site verification.
The error in prediction was attributed to the sub surface defect
Site Verification ResultsChainage Length (mm) Width (mm) Depth (%)
ROSEN(2001)
IPIG A* ROSEN(2001)
IPIG A* ROSEN(2001)
IPIG A*
I (IPIG in 2005) Site verification results of M’ sarai – A’bad PL on the basis of IPIG data
73334.87 10 9 9 13 20 18 42 42 40
73328.5 18 18 38 27 31 36 38 35 35
130706.15 13 13 14 14 18 14 45 45 42
II (IPIG in 2007) Site verification results of Patna – M’sarai PL on the basis of IPIG data
121.83 (MM 308) 15 22 20 61 35 50 21 47 32
120.07 (MM 308) 21 27 40 27 43 42 32 49 34
202.94 (MM 312) 32 23 28 43 42 42 20 54 47
203.75 (MM 312) 22 25 25 36 39 38 22 58 45
III (IPIG in 2007) Site verification results of BRN – Patna PL on the basis of IPIG data
28033.921 46 29 20 58 76 55 41 73 72.8
28908.817 27 23 20 32 50 38 40 57 59.6
28932.797 27 22 25 32 49 35 36 60 66
A*: Actual results are within acceptable limits. Quality of data depends on the cleanliness of pipeline which affect the MFL singals.
Corroded pipe surface
Corroded pipe surface
Variation in Depth (Reported – Actual) - ROSEN Variation in Depth (Reported – Actual) - IPIG
Variation in Length (Reported – Actual) - IPIGVariation in Length (Reported – Actual) - ROSEN
Summary
IndianOil in association with BARC, have developed IPIG technology for the
first time in the country.
The developmental process has undergone various phases like
conceptualization, designing, fabrication, testing, improvements after failures
The 12” and 14” size tools used for inspection of 1000 km of liquid pipelines.
The 24” and 18” size IPIG and CPIG are under evaluation
IndianOil has also created full-fledged testing infrastructure for evaluation of
IPIG components and modules of various sizes
Development of newer technology and IPIGs and CPIGs of other sizes for
liquid and gas lines are being taken up
Acknowledgments
Thanks to Dr. R K Malhotra, Director (R&D) for continuous
support
Thanks to BARC- CnID team to provide development support to
IndianOil
Our Thanks to our Pipeline Division for providing Pipeline for
testing and evaluation
Thanks to Pipeline R&D Team :
For helping in preparing the paper