Properly "fixing" leaking wells involves getting a workover rig on site and pumping 10-1000 barrels of cement. Not to mention developing a plan and submitting it to the state for the well work permit, which hopefully comes before the rig gets on site. Rigs will not do work without a valid permit. I used to be a PM for well abandonment.

Minimum cost would be in the $80k-100k range. Double or triple that if you run into any issues. My most expensive abandonment was around $400k, which was for a simple, vertical 5000ft well.