1. Lynsay Bensman 06 October 2009 Errors in Sampling/Monitoring in an Internal Corrosion Program NACE Eastern Area Conference

2. 06 October 2009 2 Goals of Sampling/Monitoring  Identify potentially corrosive species that may be present in a pipeline system  Determine corrosion rate  Determine effectiveness of mitigation

3. 06 October 2009 3 Errors in Sampling/Monitoring  Improper tests or equipment  Choosing the incorrect location  Poor timing  Improper sampling techniques  Improper sample preservation  Misinterpreting results  Missing sampling opportunities  SAFETY

4. 06 October 2009 4 Improper Tests or Equipment  Using the wrong equipment for what you are actually trying to test - Monitoring devices  Using a kit that is not the proper range  Using a kit that is expired or not properly working - Check prior to going out in the field

5. 06 October 2009 5 Monitoring Devices  What are you trying to achieve?  Do you need real time monitoring?  Are you looking for pitting?  Is erosion playing a role in the corrosion process?

6. 06 October 2009 6 Incorrect Sampling/Monitoring Locations  Representative or more severe than the corrosion in the system  Not necessarily - The easiest place - The closest place  Dilution effect  How many locations is enough?  Monitoring in conjunction with mitigation

7. 06 October 2009 7 Monitoring Locations  Coupons/probes on stick off the top of the pipeline are not exposed to liquids laying alone the bottom of the line  Coupons/probes off the bottom are not in the gas flow but allow liquids to collect if present  Coupons in flow should be as close to the bottom of the pipe as possible

8. 06 October 2009 8 Poor Timing  Liquid sample collection is not likely to yield optimum results - Right after drip blowing or removal from separators  At intervals that makes it difficult to interpret results - Consideration for injection withdrawal cycles - Consideration for chemical treatment

9. 06 October 2009 9 Improper sampling techniques  Waiting to perform field testing  Performing analyses on samples that do not contain water  Not following instructions  Air  Sample contamination

10. 06 October 2009 10 Waiting to Perform Field Testing  Reasons - Weather - Time - Training  Ramifications - Some data is unreliable if not collected immediately - Dissolved gases - pH - Bacteria culture testing

11. 06 October 2009 11 Air  Sample containers should be as full as possible to prevent reaction with air  Solid samples can react with oxygen in air leading to misidentification 4FeS + 3O 2 2Fe 2 O 3 + 4S + heat  Coupons that have been exposed to air should never be re-inserted

12. 06 October 2009 12 Sample Contamination  Liquid Samples - Should not re-use sample bottles - Grabbing a bottle that is just ‘lying around’ - Not rinsing out test kit containers - Sampling from a common tank - Re-using bacteria inoculation syringes  Pipe Samples - External environment  Coupons - Should never install a coupon if it has been dropped on the ground - Need to make sure wearing gloves when handling the coupon - Coupons should not be re-inserted if they have been removed from the system - Coupons should not be analyzed if they have been removed from the system and not properly stored prior to analysis

13. 06 October 2009 13 Bacteria Testing  Perform immediately after sample collection or pipe exposure - Prevent contamination  Serial dilution media should match the salinity of the water present in the pipeline  Should not expel any of the inoculation media  Swabs need to be taken over consistent area size  Proper labeling

14. 06 October 2009 14 Gas Testing  What are you actually testing?  Need to purge sample container or testing container  Some measurements are better performed on-site  Storage containers for gas that may contain H 2 S  What are on-line instruments monitoring  Do you need to check for O 2

15. 06 October 2009 15 Improper Storage of Samples  Samples need to be properly labeled (if further analysis is to be performed)  Liquid samples should be stored in a cool environment until analyzed  Bacteria inoculation vials should be stored at similar temperature to pipeline operating temperature Ok

16. 06 October 2009 16 Misinterpreting Results  Garbage In = Garbage Out

17. 06 October 2009 17 Misinterpreting Results  How do operating conditions affect the results? - Well work - Change in flow direction - Change in flow rate  Iron counts - Iron to Manganese ratios - Correlation to corrosion - Trending  Bacteria

18. 06 October 2009 18 Misinterpreting Results - Bacteria  Planktonic - Free floating - Liquid sampling  Sessile - Attached to pipe wall - Solids or swab sampling  Correlation to MIC - No known correlation between planktonic bacteria levels and the presence of MIC!!!

19. 06 October 2009 19 Misinterpreting Results  Do I have enough data to make a decision? - Trending  Do the data make sense? - Is further investigation needed? (e.g., no liquids are recovered from drips but leaks are still occurring in the system)  Do the data support current monitoring/sampling and mitigation?

20. 06 October 2009 20 Missing Sampling Opportunities  After pigging operations - Liquids - Solids - Swabs  As pipe is being removed from system - Liquids - Solids - Swabs

21. 06 October 2009 21 SAFETY  Safety is of primary importance!!!  Sampling is always concern when collecting a sample from a live pipeline system  Questions??? - Is there potential for projectiles? - Are isolation valves shut? - Are there concerns for being sprayed with liquids? - Are there any pyrophoric materials present?

22. 06 October 2009 22 Safeguarding life, property and the environment www.dnv.com