If you were unaware of the ownership interest it is highly likely that you do not own 82 acres of surface but that you own a mineral servitude that covers 82 acres.  If you owned surface someone in the family would have been paying property taxes.  Since that doesn't appear to be the case along with the fact that you were apprised of the interest by a landman it's probably a mineral servitude which has remained in force due to production from the wells you mention.  I suggest that you read this:

http://www.gohaynesvilleshale.com/profiles/blogs/what-is-a-servitude