Well Integrity Technical Section

Good day Well Integrity practitioners, 

Looking forward to obtain your experience and opinion on resolving plugged downhole capillary lines. 

The lines were intended to use for pumping of corrosion inhibitor, however after 2 months of pumping corrosion inhibitor chemical to downhole it was identified that all wells capillary lines are plugged. The plugging fact was confirmed by applying positive pressure into the line and no PFO observed. 

Thanks in advance for your feedbacks. 

Regards,
Tural

Tural

What is the OD and ID of the capillary lines?

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Best regards,
Henning Hansen
www.hansenpumps.com / www.aai.no
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Hello Tural,
Here are a few avenues to explore:

1. Was the product pumped a single product, or a mix of various chemicals? In case a single one, it should be easier to rule out compatibility issues... if various products were mixed they could have reacted and "gunked" the lines
2. What's the BHP gradient compared to the gradient of the chemical? Is the hydrostatic in the Chem Inj line potentially higher than the BHP at your injection point? If so, the product could potentially "free falls" all the time it gets pumped, with partial vacuum on top of the tubing... this has been known to form deposits in some circumstances... A fix would be to flush your lines every once in a while with a solvent BEFORE they get plugged... or using a spring-loaded check valve to apply additional control / make sure your chemical only gets injected if you apply positive pressure at surface

Let me know if this helps. Kind rgds.