| 1. |
- Benoit, G., et al.
(författare)
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Bare Field Joint for Subsea Pipelines, a Possible Alternative?
- 2018
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Ingår i: NACE - International Corrosion Conference SeriesVolume 2018-April, 2018Corrosion Conference and Expo 2018; Phoenix; United States; 15 April 2018 through 19 April 2018. - : National Assoc. of Corrosion Engineers International. - 9781510864405
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Konferensbidrag (refereegranskat)abstract
- In the present context of oil price down turn and enhanced competitiveness, cost saving becomes more important than ever. As part of cost reduction solutions in offshore projects, it may be envisaged to leave field joints bare on subsea pipelines instead of applying a field anticorrosion coating after welding of the joints on board the laying vessels. This approach would need to be applied to specific cases, where it would lead to reduction of cycle time and consequently laying rate improvement during offshore installation campaigns when field joint coating activities are on the critical path, like with pipeline J-laying method. Although cathodic protection is an efficient, reliable and field proven method for seawater corrosion prevention on steel exposed areas of subsea coated pipelines, a quantitative assessment of the long term behavior of the pipeline coating at the transition zone with the bare field joint is recommended in order to support such a radical change in the pipeline external corrosion protection philosophy. Therefore, a bespoke experimental setup was designed to simulate bare field joint configuration under cathodic protection over a long term exposure in seawater together with long term cathodic disbondment tests for comparative purpose. The bespoke experimental test was performed at full scale on 3LPE coated pipe section with a field joint area left bare and protected by galvanic anodes. The pipe was immersed in a vessel containing renewed seawater and half-buried in mud to reproduce actual pipelines exposure on seabed. It was heated also with an internal fluid at 65°C to simulate actual operating conditions. Long term cathodic disbondment tests were performed on 3LPE coated pipe samples with internal heating of the samples at 23°C and at 65°C. Reference samples without CP were also exposed to the same conditions. The two experimental works were conducted during 12 months. For each of the tests above, a visual assessment was performed at regular intervals together with a quantitative assessment of the disbonded area (removal and recording of disbonded coating area). With these tests, it was possible to characterize the influence, over the time (up to one year) of the temperature over the normalized cathodic disbondment test results. The effect of the cathodic protection was also evaluated. For the full scale test evaluation and characterization, comparison was made between the disbonded coating length in the mud and the seawater exposure conditions. Correlation between cathodic disbondment tests and full scale test was also drawn. In light of the results obtained so far in this study, these tests results conclude positively that the bare field joint alternative concept for subsea pipelines is possible upon certain operating temperature limitation.
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| 2. |
- Larche, Nicolas, et al.
(författare)
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Cathodic Protection in Arctic Conditions Study Assesses Corrosivity of the Environment at the Yamal LNG Carrier Terminal in Siberia, Russian Federation
- 2018
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Ingår i: Materials performance. - : National Assoc. of Corrosion Engineers International. - 0094-1492. ; 57:8, s. 26-30
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Tidskriftsartikel (refereegranskat)abstract
- Yamal LNG, one of the largest liquefied natural gas (LNG) projects in the world, processes natural gas from the giant onshore South Tambey gas and condensate field located on the Yamal Peninsula in the Arctic region of the Russian Federation. Yamal LNG will produce reserves of 4.6 billion bbl (731 billion L) of oil equivalent. The project includes an integrated gas treatment and liquefaction facility with three liquefaction trains (each with a capacity of 5.5 million tons per year), storage tanks, a port with 15 ARC 7 ice-class LNG carriers with a capacity of 170,000 m(3) each, and airport infrastructure.
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| 3. |
- Larché, Nicolas, et al.
(författare)
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Field cathodic protection study in the specific artic conditions of the Yamal gas carrier terminal
- 2018
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Ingår i: NACE - International Corrosion Conference SeriesVolume 2018-April, 2018Corrosion Conference and Expo 2018; Phoenix; United States; 15 April 2018 through 19 April 2018. - : National Assoc. of Corrosion Engineers International. - 9781510864405
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Konferensbidrag (refereegranskat)abstract
- For most projects, cathodic protection (CP) design can be performed using CP standards or existing data from literature and field feed-back. It was not the case for the particular environment of the YAMAL gas carrier terminal project, planned in Sabetta (Siberia - Federation of Russia). This particular area is located between the Kara sea and a river mouth in Yamal peninsula (Artic region). It involves very different conditions in terms of salinity, temperature, liquid/ice phases, all depending on icing/deicing seasons and on the water depth. These very specific conditions can hardly be simulated at laboratory scale and required a specific corrosion and CP study with measurements on site. The global aim of this quantitative study was to collect field data to help at defining an adapted corrosion protection system for carbon steel immerged structure (e. g. berths), and to forecast the related corrosion risks. Regarding the extreme conditions of the site, the main challenge was to design adapted arrays containing corrosion and CP sensors (to be deployed on site), to get representative quantitative data. All systems have been qualified at laboratory scale before use on field site. The deployment was successful and allowed getting actual polarization curves, and local initial corrosion data. In parallel, the stability of zinc galvanic anodes has been evaluated in this resistive environment. For both corrosion and CP data, different results have been highlighted for surface and bottom waters, and for ice & liquid phases. Modelling can now be used to assess the efficiency and select the CP system (i. e. galvanic anode or impressed current)
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| 4. |
- Vittonato, J., et al.
(författare)
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High sensitive sensors for collection of cathodic polarization data and determination of protection potential criteria of buried structures
- 2019
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Ingår i: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 13337Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019. - : National Assoc. of Corrosion Engineers International.
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Konferensbidrag (refereegranskat)abstract
- The installation of metallic coupons in the vicinity of buried pipes under cathodic protection (CP) allows theoretically to measure the potential and the current density through the simulated coating defect. Nevertheless, this type of monitored coupon does not provide direct information on the actual efficiency of the CP and corrosion rates that could be caused by a CP failure over time or not adapted CP design. According to the soil resistivity and the corrosion potential in absence of CP, a protection potential is generally targeted following the standard recommendations. However, the soil resistivity as well as the corrosion potential might depend on the seasonal fluctuations and the protection potential might vary as function of the considered standard. Moreover, all soils parameters cannot be considered in recommendations from standards and cathodic protection criteria can be sometimes debatable. In this study, very sensitive electrical resistance (ER) sensors, used for obtaining precise corrosion data in real-time, were adapted for soil applications. They were used in the selected soils and conditions to determine the off potential and current density corresponding to a corrosion rate of 10 µm/year, which corresponds to the maximal corrosion rate of buried structures considered as protected according the standard ISO 15589-1:2015. The adapted ER sensors appeared to be particularly suitable for determining the protection potential and CP criteria in a relatively short time. For the tested soils and conditions, the results showed that the cathodic protection criteria recommended in ISO 15589-1: 2015 are conservative compared to those measured experimentally. This method therefore seems particularly relevant for the determination of the protection potential in complex or polluted media, in the absence of data in the literature.
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