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3144 views
06:51 Aug-15-2006

Rolf D.

Director, Editor, Publisher, Internet, PHP MySQL
NDT.net,
Germany,
Joined Nov 1998
598
BP's pipeline testing

What lessons we can learn from BP's internal pipeline corrosion problems?
Must be pigging part of a routine, UT and/or MFL?
What other techniques should be used?

Rolf


 
07:39 Aug-15-2006

Rich Roberts

Engineering, Executive Managment
Quest Integrity Group,
USA,
Joined Nov 1998
78
Re: BP's pipeline testing The events which have taken place at BP – Prudhoe Bay are very unfortunate, however preventable. I worked at this location (previously ARCo) from 1985 to 1992 and quite familiar with the existing pipe systems covering the oil field. When I was there we use to use Neutron Backscatter to rapidly scan 100% of the lines and then follow up with manual and automated ultrasonics on those areas which contained large quantities of water. We never lost a line during the period I was there. I’ve heard that this sort of program has been drastically reduced, which has ultimately caused the line degradation to go unnoticed.

I personally would have recommended use of routine “batch” exchange pig to keep the water pushed through the lines. A batch pig is a simple device which is constructed of oversized polyurethane disk to push product or water on down the line. This would force the standing water downstream into the separation units and dealt with at this controlled location. By moving the water downsteam, theywould have most likely been able to keep the microbes to a minimum, thus reducing corrosion caused by excretion.

Ultrasonic based intelligent pigging should have also been considered as a routine monitoring system. Each line could be placed on scheduled pigging runs, which would have identified any areas where corrosion activity was present. By combining the water removal and routine monitoring BP would have most likely never had to deal with the situation they are faced with today.

----------- Start Original Message -----------
: What lessons we can learn from BP's internal pipeline corrosion problems?
: Must be pigging part of a routine, UT and/or MFL?
: What other techniques should be used?
: Rolf
------------ End Original Message ------------




 
02:43 Aug-16-2006

Godfrey Hands

Engineering,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
281
Re: BP's pipeline testing ----------- Start Original Message -----------
: What lessons we can learn from BP's internal pipeline corrosion problems?
: Must be pigging part of a routine, UT and/or MFL?
: What other techniques should be used?
: Rolf
------------ End Original Message ------------

Hi Guys,

As well as MFL and Pigging, we should also consider Guided Wave Ultrasonics.

This is especially suited to pipelines which for one reason or the other cannot be pigged.

There is one manufacturer which has low cost sensors, which can be permanently installed (under insulation) to permit data subtraction in a condition monitoring mode.
This is more sensitive than a straightforward corrosion detection mode, where corrosion in the order of 2 to 5% loss of wall cross sectional area is detectable.
Please contact me if you need more info.

Godfrey



 
04:00 Aug-16-2006

Rolf D.

Director, Editor, Publisher, Internet, PHP MySQL
NDT.net,
Germany,
Joined Nov 1998
598
Re: BP's pipeline testing

At BP's Web Site
http://usresponse.bp.com/go/doctype/1249/15644/
I found a document:
BP Corrosion Monitoring Report (pdf, 1.94 MB)
http://usresponse.bp.com/posted/1249/BP_Corrosion_Monitoring_Report.127827.pdf

From this report I extracted table 14
"Inspection / Non-Destructive Examination Techniques - Benefits and Limitations"
The table is displayed on top of this message.

Godfrey suggest in his message the use of guided waves technique, however from the table and from comments in the BP report I understand that this technique seems not to be very promising (Sensitivity: Low, Accuracy: Low).

Rolf




 
04:36 Aug-16-2006

Godfrey Hands

Engineering,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
281
Re: BP's pipeline testing Godfrey again.
Yes, the BP report does suggest low sensitivity and low accuracy. It also refers to the use of Lamb Waves, and Guided Wave technology has progressed quite a bit since those days. We now use Torsional wavse as well as Longitudinal waves and Lamb Waves. Torsional waves do not leak into the product like the other waves, so test ranges of up to 150 metres may be achieved.

Typical detection of 2% loss of wall cross section may be detectable nowadays.
Location along the pipe length in the order of 10 to 20 centimetres is possible.
I would now class the sensitivity and accuracy as "medium".
As I said before, it is more suitable for pipes which cannot be pigged, whilst pigging should be the first choice.

Godfrey
----------- Start Original Message -----------
: At BP's Web Site
: http://usresponse.bp.com/go/doctype/1249/15644/
: I found a document:
: BP Corrosion Monitoring Report (pdf, 1.94 MB)
: http://usresponse.bp.com/posted/1249/BP_Corrosion_Monitoring_Report.127827.pdf
: From this report I extracted table 14
: "Inspection / Non-Destructive Examination Techniques - Benefits and Limitations"
: The table is displayed on top of this message.
: Godfrey suggest in his message the use of guided waves technique, however from the table and from comments in the BP report I understand that this technique seems not to be very promising (Sensitivity: Low, Accuracy: Low).
: Rolf
------------ End Original Message ------------




 
06:09 Aug-17-2006
Old UT guy
Re: BP's pipeline testing ----------- Start Original Message -----------
: : What lessons we can learn from BP's internal pipeline corrosion problems?
: : Must be pigging part of a routine, UT and/or MFL?
: : What other techniques should be used?
: : Rolf
: Hi Guys,
: As well as MFL and Pigging, we should also consider Guided Wave Ultrasonics.
: This is especially suited to pipelines which for one reason or the other cannot be pigged.
: There is one manufacturer which has low cost sensors, which can be permanently installed (under insulation) to permit data subtraction in a condition monitoring mode.
: This is more sensitive than a straightforward corrosion detection mode, where corrosion in the order of 2 to 5% loss of wall cross sectional area is detectable.
: Please contact me if you need more info.
: Godfrey
------------ End Original Message ------------

5% of the cross sectional area of a 30" Diameter pipe x 0.500 thickness means a hole approximately 4" long would be the threshold level ofdetection, if I am applying the match correctly. Not what I would call acceptable, would you?



 
09:31 Aug-18-2006
M. Kim Johnson
Re: BP's pipeline testing ----------- Start Original Message -----------
: : : What lessons we can learn from BP's internal pipeline corrosion problems?
: : : Must be pigging part of a routine, UT and/or MFL?
: : : What other techniques should be used?
: : : Rolf
: : Hi Guys,
: : As well as MFL and Pigging, we should also consider Guided Wave Ultrasonics.
: : This is especially suited to pipelines which for one reason or the other cannot be pigged.
: : There is one manufacturer which has low cost sensors, which can be permanently installed (under insulation) to permit data subtraction in a condition monitoring mode.
: : This is more sensitive than a straightforward corrosion detection mode, where corrosion in the order of 2 to 5% loss of wall cross sectional area is detectable.
: : Please contact me if you need more info.
: : Godfrey
: 5% of the cross sectional area of a 30" Diameter pipe x 0.500 thickness means a hole approximately 4" long would be the threshold level of detection, if I am applying the match correctly. Not what I would call acceptable, would you?
------------ End Original Message ------------

I believe he means the cross section of the wall, but could be mistaken. E.g., if the wall crosectional thickness is 1 inch, the detectable corrosion depth would be 5% of that, or 0.05 times 1 = 0.05 inches. Or, if he meant area, it would be 0.02 to 0,05 times the annualar area for the material, itself - not the total diameter.



 
02:46 Aug-18-2006

Paul Robertson

,
Netherlands,
Joined Jun 2003
12
Re: BP's pipeline testing Following this posting with some interest, having just returned from that part of the world.

The MsS guided waves system is in use on the BP managed part of the oilfields, but usually applied at the cased pipe areas (road and caribou crossings)where there is no direct access for 'hands on' inspection techniques. There is nothing to suggest that the problem areas have been subject to any form of recent inspection, never mind guided waves technologies. I agree that sensitivity and accuracy of these techniques will not be as accurate as 'hands on' inspection techniques, this is after all remotely applied inspection.
Guided waves, whichever form of application, can be an extremely useful screening tool in limiting conditions, indeed it assists greatly in other parts of the Alaskan oilfields under the control of other operating companies.
So instead of giving a very useful technology a hard time, perhaps some members of the forum should comment on the real problem at hand in that part of the world - BP'slack of adequate inspection protocol whereby executives admitted openly that the company's program to find and prevent corrosion-caused leaks is seriously flawed.
Let's hope they make more use of many available technologies, each having limitations, but all having benefits.

Regards



 
05:40 Aug-22-2006
Old UT Guy
Re: BP's pipeline testing ----------- Start Original Message -----------
: Following this posting with some interest, having just returned from that part of the world.
: The MsS guided waves system is in use on the BP managed part of the oilfields, but usually applied at the cased pipe areas (road and caribou crossings)where there is no direct access for 'hands on' inspection techniques. There is nothing to suggest that the problem areas have been subject to any form of recent inspection, never mind guided waves technologies. I agree that sensitivity and accuracy of these techniques will not be as accurate as 'hands on' inspection techniques, this is after all remotely applied inspection.
: Guided waves, whichever form of application, can be an extremely useful screening tool in limiting conditions, indeed it assists greatly in other parts of the Alaskan oilfields under the control of other operating companies.
: So instead of giving a very useful technology a hard time, perhaps some members of the forum should comment on the real problem at hand in that part of the world - BP's lack of adequate inspection protocol whereby executives admitted openly that the company's program to find and prevent corrosion-caused leaks is seriously flawed.
: Let's hope they make more use of many available technologies, each having limitations, but all having benefits.
: Regards
------------ End Original Message ------------

Sorry if I stepped on a toe or two, as that was not my intention. I was simply pointing out that the technology is NOT a be all end all that was implied by the previous poster Godfrey. As you rightly point out, BP has admitted their program had shortfalls, and they will address them (I know this to be true, first hand)using whatever techniques fit the situation at hand. There are many challenges present, and no single inspection technique will solve all the issues. And lets not also forget, that BP is only the recent owner of these lines. Having assumed operation and ownership only a few years ago.


 
07:54 Mar-23-2007
singhal sk
Re: BP's pipeline testing I would like to have copy of BP report. Please proivde as the same is not available at URL


 


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