ESP Gradual Loss in DP - Stages Failure?

[xavyluna1]

Hello ESP specialists,

I have limited experience in artificial lift and would appreciate discussing an ESP failure scenario in one of our wells installed with an ESP.

Well A:
Oil potential 350 STB/D.
Water cut 10%
Depth @ gauge 830 m TVD ss
Deviation 59deg

ESP pump:
150 stages
60 Hz

Background:
Well online producing c. 1,100 psi DeltaP (PIP 200psig vs Pdischarge 1,300 psig).
After a shut-in period, the ESP was restarted but the DP was not achieved; PIP high. It was suspected that stages within the pump have failed and pump kept running.
About a week later, the DP has reduced further and ultimately the pump's stages have failed; no recorded production.

Query:
From the brief outline above and looking at the uploaded DP trends, I was wondering if this is something you have come across in your experience; any conclusions on this type of failure (mechanical or other); or possible interventions to fault-find/confirm/re-start the ESP.

Possible interventions:
Re-circulating hot oil to dissolve/free-up possible wax/paraffin precipitated during changes in P/T to surface; sometimes successful.
Bullheading hot water into well/tubing reservoir.
Reverse flow an ESP to free-up/clean internals.
Start-up at a higher power (up to 80 Hz).

What is interesting in well A is that lab test showed some type of formation mud (heavier than water) being produced from the formation; not clearly understood.

Would pumping heavier mud-type fluids prove destructive to running the ESP long term?
If so, would a strategy of periodically washing/re-circulating via tubing and via casing be something already implemented in the industry?

Thanks for your insightful thoughts and please feel free to discuss further.

Appreciate your patience as my ESP development progresses.

Regards,
X

 

[zdas04]

This is pretty common. We see first stage cavitation damage really often. If you keep running with the first stage not pumping, then the next low pressure transient will cavitate the second stage, etc. It doesn't take long before the non-cavitated stages cannot develop enough head to discharge into the tubing and production goes to zero. There are some kinds of ESP problems that can be fixed without pulling the pump, but I'd be really surprised if this is one of them.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist