pl corrosion defect&remedy

D/Stream Pipeline Corrosion Defects &

RemedyPipeline & Storage Tanks Integrity Assessment

Workshop5th December, 2007

Alsalam Rotana Hotel- Khartoum

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Greater Nile Petroleum Operating Company Limited

5th December , 20072

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Great Nile Petroleum Operating Company Limited

Asset Integrity Workshop

GNPOC Pipeline: Corrosion Defects

& Remedy.By: Pipeline Operations & Maintenance Department

December 2007.

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GREATER NILE PETROLEUM

GNPOC Pipeline: Corrosion Defects & Remedy.


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• Introduction:In year 2001, intelligent pigging (IP) detected 2points metal loss depth (ML) more than 40% and 130points with ML less than 40%.5 points were repaired using Clock Spring Method that will be discussed later.

In this year 2007, IP result showed serious corrosion defects in terms of metal loss (ML) and severe welding anomaly (SWA) and general pitting in total 20,233 points.Details results of findings by CPP (China Petroleum Pipeline Bureau) as shown in the next slides.


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Inspection result comparison between 2001 and 2007 中国石油天然气管道局China Petroleum Pipeline Bureau(CPP)



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• The following slides showed the inspection and remedial actions being performed on the following KP locations.

a. KP (0 + 905m)b. KP (0 + 917m)c. KP (0 + 20m) to KP (0 +25m)d. KP (0 + 320m)

• In this presentation, we will showed on the severity of thecorrosion defect being observed on the pipeline surfaces at this KP and what remedial action had been taken to rectify the situation.

• Note: Pipeline size and description:28”Ø x 10.72mmWT API 5L X65 pipe 3LPP (three layer polypropylene) coating.


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1st September 2007: Scenario of KP (0 + 905mm) location i.e. a swampy area before any civil

work commenced.



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3rd September 2007: Location of KP (0 + 905mm) before excavation being done. Note that the swampy areas as shown in previous slide were dumped with dried black

clay and gravels before excavation can be proceed and total cost incurred for such civil & excavation work was USD7,000 (USD seven thousand).



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8th September 2007: Upon completion of excavating the KP (0 + 905mm) location, the existing shrinkage sleeve on the welding joint area was observed damaged, bulging in most areas where resulted water and damp soil filled the gap between the sleeve and pipe surface areas.



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Upon removal of the damage shrinkage sleeve condition, the pipe surfaces and welding joint profiles were observed

to be severed pitted with severe Metal Loss (ML) and under-bead welding profiles.



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Other areas of the pipe surfaces that have been corrosive attack.



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Upon completion of cleaning the corrosive defect areas by power brushes, severe ML could be seen clearly.



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Other affected ML areas observed.



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Depth of the severe pitting surface that was accessible to be measured by pitting gage (pipe pit gage) recorded approximately 0.230inch (5.8mm)

depth about 54% ML.



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Thickness of pipe on the defect ML areas were measured on four (04) severe locations that can be measured and the readings recorded were

between 4.7mm to 5.2mm thick.



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The affected ML defect areas were thoroughly cleaned and fill with cold weld compound materials as per manufacturer application methods and left for curing and hardened.Cold weld compound materials: DURAMETAL – SUPER CA-HD RAPID



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Fit up of the Type B fabricated welding sleeve upon curing of the cold weld compound.



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- Welding started after the Operating Pressure was reduced to the minimum that possible and stabilized at 58Bar. - Welding of the fabricated sleeve was done accordingly GNPOC WPS No: 02, 03 and or 04. - Work instruction & procedure for welding of the fabricated sleeve type B were derived and followed for the welding of this sleeve.



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Work Instruction & Procedure for Welding of the Fabricated Sleeve Type B

• Before welding of any welding sleeve on live pipeline can commence, the operating pressure of the pipeline need to be reduced as per calculated “safe” pressure level for welding onto in-service pipelines such as by using the following formula: P = 2S (t - c) 0.72 / D as per Pipeline Repair Manual by Pipeline Research Council International Inc. (PRCI).Where:P = pressure (psi)S = specific minimum yield strength of pipe (psi)t = nominal pipe wall thickness (inch)D = nominal pipe diameter (inch)c = allowance for heated metal loss of strength, assume to be 2.4 based on TD Williamson calculations.



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• Removed all coating material of the line pipe on the areas where welding to be performed.

• GNPOC Welding Procedure Specifications (WPS) No: 02 and 03 or 04 to be used for the welding of this fabricated sleeve type B. Welding parameters, preheat temp, inter-pass temp and pipe wall temperature to be monitor accordingly to the mentioned WPS used.

• Upon curing and hardened of the cold weld compound materials (DURAMETAL-SUPER CA-HD RAPID), fit-up of the fabricated welding sleeve type B to be done properly with accepted alignment root gap to be achieved. Advisable to hold and tight up the two portion of the this sleeve by the use of two numbers of chain clamps, fiber strap clamps or any clamping devices.



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• Only Low Hydrogen Electrodes E 7018 to be used for welding of these sleeves and ONLY use electrode E7018 that have been baked at 300degC for 2hrs or as per recommended by the electrode manufacturer.

• Ensure that all E7018 electrodes that are to used during welding are kept in a quiver (small portable oven) having a temperature of 70degC.

• If there are gaps of more than 5mm between the fabricated welding sleeve to the pipe surface circumferentially, advisable to butter weld the pipe surface first using E 7018 size 3.2mmØ as per GNPOC WPS no: 03, before welding of the mentioned sleeve to the pipe can be performed.



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• Welding sequences if possible to be as follow: a. Start and complete the longitudinal butt weld 2G position first.b. Upon completion the longitudinal butt weld, then proceed with the 3F circumferential fillet weld.

• Preheat the welding joint areas to the temperature to a minimum of 100degC before welding can start.

• Monitor the pipe surface temperature near the welding pools to be not more than what recorded in the above mentioned GNPOC Approved WPS (s) i.e. must be <400degC.

• Upon completion of welding, acceptance of the welding profiles to be justified by visual inspection (VI) and in addition to VI, NDT (non destructive test) either by Magnetic Particle Inspection (MPI), Dye Penetrant Test (DPT) OR Ultrasonic Test (UT) to be performed on the welding profile to confirm the acceptance of the welding profiles.



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Welding of 5F Circumferential Fillet position in progress.



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Completion of welding the fabricated sleeve. Total welding time taken to complete welding of this fabricated sleeve type B was approximately

5hours. Note that only two (02) welding machines and three (03) welders were available to perform the welding job.



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Upon completion of welding and visual inspection, Ultra-sonic Testing (UT) was performed and result of UT was observed satisfactory.



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Upon completion of NDT by Ultra-sonic Testing, application of Epoxy Coating was done on all welding profile areas and exposed bare pipe surface. Type of Epoxy Coating Material: Raychem S1239 Adhesive .



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Upon curing time of the epoxy coating, the fabricated welding sleeve and its nearby surrounding areas of the pipe were wrapped with the heat shrinkable sleeve. Type: RAYCHEM, HTLP 80, High Temperature (80degC)



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Photos of repair job on other locations.



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Example of joint surface condition upon removal of shrinkable sleeve at KP ( 0 + 917m)



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Further removal of the 3LPP coating of the 28”Ø existing pipe at KP ( 0 + 917m).



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Existing Heat Shrinkable Sleeve found wet after removed from the pipe surface at KP ( 0 + 917m)



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Location: KP (0 + 20m) to KP (0 + 25m)Pipe Spool surface condition upon removal of shrinkable sleeve.

Note that these portions of pipe spool was only covered by shrinkable sleeves ONLY.



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Further example observed between KP (0 + 20m) to KP (0 + 25m)



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NDT method using Magnetic Particle Inspection (MPI) performed upon completion of welding of fabricated sleeve type B

at KP (0 + 20m)



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Another photo for MPI in progress.



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Existing Mechanical Clamp being removed at KP (0 + 320mm)



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Upon removal of the present Mechanical Clamp at KP (0 + 320mm):The condition of the cold weld material on the pipeline surface applied

earlier before installing a mechanical clamp being observed as shown in the below photo. This area was thoroughly cleaned by using power brush &

hand grinder before fit-up of fabricated welding sleeve type B.



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Optional Remedy Methods:

• Besides welding of fabricated welding sleeve on the corrosive defected areas, optional methods to be considered are to execute the followings:1) Installation of HT (High Temperature) Clock Spring materials.2) Installation of SpiderWrap (High Strength) HS material.



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RR

The Fast, Economical Solution for Permanent Pipeline Repair

DOT Approved for repair of Gas & LiquidDOT Approved for repair of Gas & LiquidPipelinesPipelines

The Clock Spring CompositeThe Clock Spring CompositeSleeve Reinforcement SystemSleeve Reinforcement System

Permanent 50 year repair….. Over 100,000 installed worldwide…

CLOCK SPRING



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CLOCK CLOCK SPRINGSPRING

RR

Proven better, time after Proven better, time after timetime

• Clock Spring for the reinforcement of corrosion and mechanical damage restoring the pipe integrity to its pristine condition.


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CLOCK SPRINGCLOCK SPRING RR

Proven better, time after Proven better, time after timetime

1. Patented, high-strength, unidirectional composite structure

2. Patented, fast curing, high performance two-part adhesive system

3. Extremely high compressive strength, proprietary load transferring component. Once installed, the three elements bond together to form extraordinarily strong and durable repair


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SPIDERWRAP HIGH STRENGTH (HS) WRAP

SpiderWrap HS is an innovative, high strength piping remediation wrap. It consists of a proprietary glass fiber reinforcement fabric, factory impregnated with durable, moisture cured polyurethane (MCU) resins.

SpiderWrap HS offers complete external piping remediation, repair, reinforcement, and/or completehoop strength replacement to any size piping, constructed of virtually any material, and it’s flexibility allows installation on any shape or configurationIncluding elbows, manifolds, tees, reducers, bends.

SpiderWrap HS is an efficient, economical, easy to use alternative to any other repair product, or replacement.

SpiderWrap HS is highly chemical resistant, non-conductive and temperature resistant to more than 650 deg. F. after cure.

SpiderWrap HS is a proven product, currently successfully used in numerous applications in many industries worldwide.


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GENERAL PREPARATION AND APPLICATION PROCEDURE • Clean pipe surface to as near white metal as possible • If pitting is present, fill pits with one of our specified epoxy fillers • Coat the surface to be wrapped with BD-563 Epoxy Base • Install the SpiderWrap HS to the calculated specified number of layers, wetting continuously • Pull each layer tightly and work into previous layer for bond • Smooth and wet continuously, then install 2 layers of the retaining stricture banding over the top layers to

assure a smooth finish and monolithic reinforcement

MECHANICAL PROPERTIES Operating Temperature -65º to 650º F. after cure

Tensile Modulus 3.8 x 106 psi ASTM D3039 Tensile Strength 65,000 psi ASTM D3039 Flexural Modulus 3.6 x 106 psi ASTM D3039

Flexural Strength 53,100 psi ASTM D3039

Ply Thickness .011 inches (11 mils) Compressive Strength 28,500 psi ASTM D3039 Dielectric Strength Non-conductive when cured (16,000 volts) Working Time 20-30 minutes, temperature dependent 85

shore D Hardness nominal

Load per ply per Inch or 715 pounds width

Load per ply per Inch for 425 pounds 20 year+ life designs Allowed for “D.O.T.” pipeline repairs under 49 CFR, Parts 192 and 195, as well as Code Compliance being validated and certified for use under the ASME PCC-2 Article for B31.3, B31.4 and B31.8.

One year if stored between 40°--83°F and Available

aluminum packet is not punctured. Do not Sizes Shelf Life use if product is hardened. Rotate stock for best results.

Hydrochloric Acid Ammonia MEK NO EFFECT Diesel

Chemical Resistance Acetone Crude Oil

(40 Day Immersion Test Toluene

Ethyl Alcohol Period) Gasoline

Black liquor Xylenes Sulfuric Acid

Cure Time 1 hour at temperatures between 50°--80°F 3801 Kirby Drive, Suite 520, Houston TX 77098

Tel: 713-828-1318 • Fax: 713-630-0560

2” X 12’3” X 10’

3” X 30’

4” X 15’

4” X 30’

4” X 50’

6” X 60’

10” X 60’

10” X 120’


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THE ENDThank you for your kind

attention.Shukran Jazilan.

Wassalam………….


pl corrosion defect&remedy

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