If an oil well is completed within 330' of a lease/unit line (without an exception), is it an illegal well?
What are the repercussions from the operator/leaseholder's point of view if that happens?
The 330' set back that is typical of Haynesville Shale units is not applicable to oil wells. Without specific information it is impossible to provide an accurate answer. Oil units come in varying sizes: 40 acres, 160 acres, etc. Oil units are commonly smaller than the ~640 acre Haynesville unit. They are based upon the calculation of the area that one well can drain. So it depends on the size of the unit and when the well was drilled if it is an old well.
Sorry, Harold. That is insufficient information to make an informed decision. If you don't want to identify the specific well in an open discussion, you can private message me on my member page and I will try to look at the specifics. Spacing rules for oil wells depend on the formation being produced and the era in which the well was permitted.