Pipeline Integrity through Coatings and Cathodic Protection

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1 ICEPIM 2015 International Conference on Pipeline Integrity management Pipeline Integrity through Coatings and Cathodic Protection A.S.Khanna Corrosion Science & Engineering, Department of Metallurgical Engineering IIT Bombay

2 Oil & Gas Installations Oil & Gas production is the life line of every country. To keep the targeted t production, it is required to keep smooth running of pipeline, without unplanned shutdowns and accidents. Oil & gas production starts from Deep wells, Offshore platforms, underground pipelines for crude/gas transportation and finally storage tanks and refineries. Though efforts are made to keep them best running, but the best way to maintain the asset is by proper Corrosion management.

3 Corrosion Management In simplest form, corrosion management like business or finance management is to look all issues required to control corrosion. These are described as : Better material selection methodology which at first place gives lower corrosion rates. Protection by one of the controlling methods: Coatings, cathodic protection or use of inhibitors. Online monitoring to check the health of the plant. Failure Analysis and R &D input to improve the initial input on control strategy. Periodic maintenance to repair faulty portions

4 Pipelines Is the most important link to oil and Gas production. It is very important to keep this asset properly maintained without any leakage, failure or possibility of force shut down. So what is required: Pipeline Integrity Approach

5 Total Pipeline Integrity Higher Productivity Greater safety Longer Life

6 Pipeline Accidents In 1999 gasoline pipeline explosion in Bellingham, Washington, killed two children and an 18 year old man, and caused $45 million in damage to a city water plant and other property. In 2000, a natural gas pipeline explosion near Carlsbad, New Mexico, killed 12 campers, including four children. In 2006, damaged pipelines on the North Slope of Alaska leaked over 200,000 gallons of crude oil in an environmentally sensitive area.

7 Pipeline Safety Issues First, those related to vandalism, pilferage, sabotage, terrorism. These issues cannot be tackled by Engineers. These may be taken care by additional securitymeasures measures, policing, regular inspectionofof the asset. Pipeline Maps A very important aspect to know the routes, find out vulnerable areas, sensitive locations, new sites ready for development etc. Taking care of leaks and defects during fabrication, installations, corrosion protection measures, especially coatings and cathodic protection Use of online monitoring techniques and also remote sensing provisions, such as pipeline data using SCADA etc. Periodic survey and detailed monitoring after definite intervals such as Intelligent pigging after 5 years intervals Integrity management issues to the gas and protection. crude handling and transportation agencies: g pgg g y

8 Integrity Approach to Pipeline Coatings

9 Integrity Meaning How to apply the highest ethical standards to every aspect of the business. Adherence to moral a nd ethical principles soundness of moral character honesty. to preserve the integrit y means, sound, unimpaired, or perfect condition.

10 Point to Ponder? Is Zero risk is achievable in Engineering Structures? Can we avoid Pipeline failures? What is the effect of Ageing with time, changing conditions, external threats and always fear of human errors? Managing pipelines with better skill, training, inspection and repair is the only solution

11 Why Failure Occur Failure of Coating Failure of CP ( Non availability of power) Internal Corrosion ; SCC, SSCC Reasons Organizational failures Wrong design Unsafe supervision Poor maintenance

12 Pipeline Failures Statistics Pipeline Data USA Failure in Onshore UK Pipelines Phil Hopkins, J Pipeline Engg, 2008, p69

13 Pipeline Integrity Management Plan (PIMP) Pipeline integrity management is a process for assessing and mitigating pipeline risks in an effort to reduce both the likelihood and consequences of incidents. PIMP is a systematic and comprehensive process designed to provide information to effectively allocate resources for the appropriate p prevention, detection and mitigation activities. The program builds on the existing foundation of pipeline safety regulations covering design, construction, testing, operation and maintenance that has been in place for manyyears years.

14 How Pipeline Integrity Approach can help to achieve coatings which give design life without any failure Best coating selection is based upon the severity of the pipeline terrain. Assure best surface preparation with proper surface cleanliness ( min. Sa2½ ), depth po profile eand min. impurity level. ee Proper application conditions and optimized parameters to achieve a coating with : Uniform thickness High cathodic disbondment Minimum i i or no holidays High Impact strength Good ageing characteristics ( in case PE Coating) Assured damage free transportation to the site Good quality of Girth weld coating followed by proper ditching of the pipeline

15 Basic steps in the integrity management process Identification of High consequence area (HCA) High population density areas or Difficult to evacuate facilities, such as hospitals, prisons or schools, churches, office buildings, or playgrounds. Threat identification and risk assessment Identification of Pipeline segments with possible threats of concerns such as heavy rains, land slide etc. Risk Analysis Potential hazards from facility operation are identified, and the likelihood and consequences of potential adverse events are estimated. Each pipeline segment is given a numerical score based on the estimated risk.

16 contd. Baseline assessment plan Development of baseline data from the 10 year assessment of the pipelines. Integrity assessment Mthd Methods Inline inspection smart pig, is run through the pipeline to evaluate the pipe s condition. Pressure test Direct Assessment a structured, multistep evaluation is conducted to identify potential problem areas. Remediation Potential integrity concerns identified during the integrity assessment are evaluated and actions are taken to eliminate the problems.

17 Example of Pipeline Integrity

18 Issues in Basic Design of Pipeline Better pipeline material selection to avoid, pitting, SCC, sulphadic corrosion. External Coatings backed by Cathodic Protection Internal Corrosion by thin epoxy coatings or by inhibitor injection

19 Chemical composition of various steels used for underground dcross country pipelines Element Grade C Mn P S Cr Cu Ni Mo Al Si Nb/Ti Yield Strength X (MPa) UTS (MPa) X X X X X l X /

20 CORROSION CONTROL IN PIPELINES COATINGS CATHODIC PROTECTION INHIBITORS External Coating Internal Coatings Inhibitors Cathodic Protection

21 Internal corrosion requirements Usually by adding inhibitors In case of sour pipelines, internal coatings is a must. In case of sea pipelines, internal metallic coating of Hastealloy is done

22 Main Purpose Internal Coatings To reduce the drag of fluid crude/gas For Corrosion resistance Requirements Coating should ldbe thin, adherent, uniform thickness, abrasion resistance Strong resistance to chlorides/sulphur based gases Should be applied uniformly by some internal jet arrangement after best surface preparation

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24 COATINGS REQUIREMENTS High Corrosion resistance High Cathodic Disbondment High Impactresistance High resistance to soil stresses High Bending resistance and flexibility Free of Holidays High Dielectric Coefficient Low water permeability

25 Classification of UCC Pipeline Coatings Coal Tar Coatings Fusion Bond Epoxy Coatings Single layer Dual Layer Three Layer PE Polypropylene Coatings ( HT application) Liquid Coatings Solventless Epoxies Elastomeric Polyethylene Tapes Rehabilitation Coatings Field Joint Coatings Internal Coatings

26 How Pipeline Integrity Approach can help to achieve coatings which give design life without any failure Best coating selection is based upon the severity of the pipeline terrain. Assure best surface preparation with proper surface cleanliness ( min. Sa2½ ), depth profile and min. impurity level. Proper application conditions and optimized parameters to achieve a coating with : Uniform thickness High cathodic disbondment Minimum i i or no holidays High Impact strength Good ageing characteristics ( in case PE Coating) Assured damage free transportation to the site Good quality of Girth weld coating followed by proper ditching of the pipeline

27 Bad surface finish leading to coating df defect

28 Surface Cleanliness Must be free from oil and grease NaCl Standard to be followed SSPC ISO

29 How can this be achieved Suitable Design of pp pipeline as per the terrain. Dedicated supervising team to supervise all the operations of surface preparation coatings, packing and transportation. Third party inspection, PQT Inspection of initial raw materials as per their specifications.

30 Schematic of Three layer PE Coating Shot Blasting Pre heating Fusion Bonding of Primer Epoxy Quality Check Quenching Adhesive coat & PE Extrusion Transportation

31 Coating Conditions Primer layer Electrostatically charged epoxy powder on heated pipes ( o C). Adhesive layer helps to bind FBE to PE Polyolefine is applied before the gel time of the epoxy coating. Temperature is about t o C. PE Extruded Layer On the Adhesive coated layer the PE is extruded over it. Its temperature is maintained at 238 o C.

32 . Critical Issues Maintaining uniform thickness Application timings for Adhesive And PE layer before FBE gels Powder Coating of Epoxy Extrusion Coating of Adhesive & PE

33 Relationship between temperature of Epoxy coating and the time of adhesive coating Application Window 60 Time befo ore applicatio on of adhesiv ve Pipe Temperature

34 PRE QUALIFICATION OF THE COATING Complete Holiday Checking Impact Test at every 1 foot followed by Holiday Detection Peel Test CD 65 o C, 2.5V, 48h CD Test 65 o C., 1.5V, 30 days Checking the Holidays Indentation of PE at RT and 65 o C. Heat & UV Ageing of PE for 105 days ΔH of applied FBE to find out the extent of curing

35 Indentation Test for Pipeline Coatings

36 Cathodic Disbondment Test Room Temperature Test 28 days High Temperature Test 65oC 28 days PQT Test 24h at 25V 2.5V or 48h test at 1.5V 15V

37 Testing of FBE Powder Properties TG1, TG2 and H

38 AUDIT OF HBJ PIPELINE

39 Example of Excellent Coating after 16 year of Inspection 3 Layer PE Coating

40 Another Example of same Pipeline

41 Example of bad coating after 5 years Reasons Bad conditions during application moisture condensation

42 Another example of bad coating Reason NaCl impurity during surface preparation

43 The main reason was that impurities remained on the shot blasted pipeline Resulted in the complete disbondment in less than 3 years Remedy Introduced Phosphate Pre treatment after the blasting just before sending the pipe for heating and coating Booth

44 Field Joint Coating Integrity of a Pipeline to great extent depends upon the Soundness of the FJC The welding of pipes makes this area quite vulnerable to corrosion. Hence selection, application and testing of the FJC still remains a critical area.

45 Welded pipe after shot blasting Heating method, whether by torch / Induction Decides the soundness of the FJC Application of Epoxy Primer on a Field Joint Prior to Heat Shrink Sleeve

46 Pipeline Integrity can be achieved by avoiding following failures fil External corrosion Use of Coating Use of Cathodic Protection Internal corrosion Internal coating Corrosion inhibitors Others like weld etc.

47 Coating & Cathodic Protection Total Cost Cost Coating Cathodic Protection 0 % 100 %

48 CP for coated pipeline Anode bed + CP Current TR

49 Monitoring external corrosion Inspection of Cross country pipeline (OISD 138) PSP at drain point Fortnightly PSP at test lead points Quarterly Pearson survey Once in three yrs. CPL Survey Once in five yrs. I/J Coupling inspection Once in year Soil testing Above ground piping Once in five yrs. Once in a year

50 Thank you