depends on the conditions of the lease and what you do with your land now, if the lease is for mineral rights and they are using horizontal drilling make sure that in the lease has a "no surface activity clause" that way you will never know they are even there. If on the other hand it is for drilling or storage be sure that you will not want to use your property that is leased. Keep in mind many of their leases are in effect as long as they want not you. You should get a lawyer that specializes in oil and gas lease and tell him what conditions you want, he should also be up on the current fair price. Be careful to check about eminent domain laws in your area, if you get to resistant they will take you to court and they will win.