I received a lease for 80 acres of mineral rights (severed from land) and some oil company wants to drill I didnt even know I had until a phone call

I got a call from someone saying that a great-great-great grandparent owned the mineral rights to 80 acres, died in 1956 without a will, and now an oil company wants to lease it and drill. The lease is a paid up lease, its for 5 years, and it has all the people's names that it passed thru that are deceased, my parents, grandparents, great grand parents, ect. This oil company currently has wells in the area that are producing. I don't like the fact that it goes on and on about pooling interests, and I don't understand it. It talks about bonuses and royalties. I need someone to see it that knows what they are reading and can advise me on what to do or not to do. Do I go to a land man or to an attorney. Or ignore it or ask for more.