Bleeding off injection well

[moredrilling]

Hello all,
We recently had to bleed off an injection well due to high casing pressure. After purging the well, we collected oil and water samples. I am curious to know how Oil ended up in the casing, is this an indication of casing leak? We are testing the water to see if it is formation water.
I appreciate suggestions.

Thanks

 

[sraesttam]

I'm assuming the tubing x production casing annulus had the high casing pressure. Is this correct?

As you suggest, you could have a casing leak. Was the casing pressure the same as the tubing pressure?

Production facilities have some oil carryover that makes it to the injection / disposal system. Do you think that you could be flowing back oil that you injected and it leaked through a leaking packer or hole in tubing? Did you have a facility upset that cause you to inject some oil? Was the injection well shut in for a while that would allow for some of the injected oil to float to the top of the column?

Are you injecting into a productive zone that contains oil? You could be flowing back oil from the productive zone. (I have never seen this.)