Corrosion monitoring data

[RobCab]

Hi,

We are currently using LPR projecting pobes in our corrosion monitoring program of our oil production field. We however have some problems on assessing the reliability of the data it provides us. We can see some important and sudden increase and decrease of the corrosion rate sometimes that have apparently no link to process matters or chemical treatment. If we look at the voltage info it occurs each time the voltage is falling under the usual 20mV.
The supplier informed us it was due to the presence in ATEX zone so the voltage had to be lowered in order to keep the current in the ATEX limits, however I'd like to have the support from someone external because this happens even when corrosion rate and thus current is pretty low (1mpy - 0.03mA).
Thanks in advance for your support !

 

[SJones]

Have you ruled out fouling by deposits or hydrocarbon? You say 'oil production field' - for LPR monitoring, it really need to be a water production field with a bit of oil.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[RobCab]

We install LPR only where there is over 90% water to avoid systematic fouling of the electrodes and we also try to put them the most possible at the bottom of the pipe. Fouling can happen but generally we get a decrease (or 0mpy) of the rates because the deposits are non-conductive. If fouling was the cause could it make the voltage drop ?

 

[SJones]

It wouldn't appear to be the case. I'm far from an expert so I would defer to trying to sort it out with the equipment manufacturer. Do you have adjacent access fittings that you can put a hi-res ER probe in to try and pick up some event correlation?

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.