PIPELINE INTEGRITY CONFERENCE BHR GROUP 5th-7th NOVEMBER 2008 SCHIPOL, THE NETHERLANDS PIPPELINE IN INDIA

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1 PIPELINE INTEGRITY CONFERENCE BHR GROUP 5th-7th NOVEMBER 2008 SCHIPOL, THE NETHERLANDS REHABILITATING A MAJOR OIL PIPPELINE IN INDIA K.G. GUPTA, INDIAN OIL CORPORATION LTD, INDIA R. JOHN, BERRY PLASTICS CORPORATION, UK.

2 Background; Details of IOCL network, coatings used, cathodic protection / internal pigging/ dig up surveys used to evaluate condition of pipeline coating. IOCL s pipeline network consists mostly of product and crude oil pipelines. The network consists of 12 product pipelines with diameters from 8 inch to 18 inch and 3 crude oil pipelines in the diameter ranging from 24 inch to 42 inch. The total length of these lines is 9,293 km. Majority of the pipelines are laid before 1996 and coated with coal tar enamel. Since 1996 IOCL has been using hi-performance coatings like 3LPE, dual FBE etc. Since 1996 practice of over the ditch coating has been discontinued. Entire network is provided with impressed current cathodic protection system. Pipe to soil potential is measured at the test lead points located every kilometer in each quarter. As an internal corrosion mitigation measure the pipelines are pigged once in every 3 months, on special occasions pigging frequency is increased. In all product pipelines corrosion inhibitor in 6 ppm For internal corrosion monitoring purpose, corrosion probes and coupons have been installed in every crude oil pipeline PSP surveys and other specialized coating condition assessment surveys, CAT/ DCVG/ CIPS etc., are conducted regularly. 2

3 Brief summary of how long the pipeline to be rehabilitated has been in service, diameter, length and product transported. This pipeline system has been in operation since 1978, major portions were commissioned in 1981, a third portion in The diameter of the pipeline is 28 inches and 24 inches. The 28 inch section is 418km long while the 24 inch is 803km long. The pipeline system is engaged in transportation of crude oil. Rehab Plan ; Remaining lifetime of pipeline? Performance of Cp system (Do you have a copy of the potential survey chart?) New construction versus recoating costs? Climatic conditions and soil types? Operating pressure comments? Amount of steel repairs estimated to be done. IOCL desires a life of 50 years for the system under consideration. Already the oldest pipeline in IOCL is in operation for 44 years. The remaining life of this pipeline could be something between 25 to 30 years. The CP system performance for most the pipeline section is satisfactory but current consumption is gradually increasing. In some of the portion CP system is unable to provide full protection. We do analyze Pipe to soil potential graphs every quarter. The cost of new constructions has been accurately calculated as 3 times that of recoating cost. The climatic condition is mostly dry with monsoon rains lasting for 2 months. In certain small portion of the pipeline the water table is high. Along the pipeline route various types of soil is encountered viz. black cotton soil, alluvial type ( small stretches) also large stretches of rocky areas can be found. Pipeline is operated at 65% of SMYS and generally operated at designed pressure with occasional reduction in pressure for repair of weak patches. Since commissioning, steel repairs made with sleeving is carried out in nearly 1% of pipeline length to take care of corroded patches. But majority of repair has been necessary since

4 In the past repair of coating was mostly undertaken though liquid coal tar enamel. The performance of which was not satisfactory. PU coating of about 11km of 42 inch diameter pipeline was tried about 6 years ago but needs carefull application control. The primarily reasons for using cold applied tape is ease of application, speed of application and lesser need for inspection. Double faced cold applied tape is used to get better adhesion between outer and inner wrap. Application of double-faced tape Coating application is done over sand-blasted SA2.5 cleaned steel but does not require the consistant high standard as that needed for good PU coating. Final CP results after recoating with double-faced tape shows significant reduction in current density. The reduction in current requirement is around 30%, with inprovements in PSP level. 4

5 Graphical Representation for CP Potential Before and After Coating Rehabilitation 5 PSP (-V) w.r.to CuSo Chainage (KM) Before Rehabilitation After Rehabilitation

6 DAMAGED CTE COATING MANUAL REMOVAL OF CTE COATING MANUAL GRIT BLASTING CHECKING OF SURFACE PROFILE 6

7 HAND WRAPPING MACHINE MANUAL APPLICATION OF INNER TAPE USING HAND WRAPPING MACHINE MANUAL APPLICATION OF OUTER TAPE USING HAND WRAPPING MACHINE FINISHED COATING 7

8 Conclusion 1. Rehabilitation is economically at least 3 time more attractive than pipeline replacement. 2. Cold applied tape has given satisfactory results on CP system. 3. The cold applied tape has been in service for last 6 to 8 months, to fully evaluate its performance more time is necessary. 8