If anyone could help me out with a situation that has come up I'd be very appreciative.

Some background is needed:  30 years ago my wifes family inherited 120 acres in western Union parish.  This land has leased numerous times over the years to different companies.

3 years ago a company leased only 40 acres of this tract even though all 120 were available.  I never did understand why they didn't want the entire tract but I always looked after the timber end and never was involved in the leasing.

Last year Pine Belt leased the other 80 acres.  When the lease on the other 40 ran out in december, 2011 we contacted Pine Belt about leasing the rest.  We were called by a landman for another company that is leasing for SWN.  He was ready to lease and said he'd get back to us.

Well, today he called and said they'd discovered Exxon Mobil had a "servitude" on this land and they may not be able to lease.  What I don't understand is what a servitude is and how could all these companies that leased in the past not have found this. 

There was a well drilled back in the 70's that was a dry hole.  This wouldn't have anything to do with that well would it?  I don't see how it would since it was abandoned more than 34 years ago.  If any one knows anything and could advice me on how to proceed I'd sure appreciate any help.  He didn't say 100% the land couldn't be leased but said it didn't look good.