Some states, TX is one of them, allows the mineral rights (what's below the ground like coal, oil, and gas) to have seperate ownership. By default all land in TX has ground rights and mineral rights together. You can sell your mineral rights to someone else. What happens here is a "group" will come around to farmers and other land owners and offer them an amount for their mineral rights. Most take it because they don't have any intentions of drilling for oil on their property due to the cost of finding it. So, the money sounds good. This "group" takes all of these properties (mineral rights) that they have purchased snd groups them together in a "lot". These can be 10's of thousands of acres. Oil companies buy them. Now, they have the right to get what is under your property. They can come and place a rig and drill on your property and take the oil. They only have to pay you a small monthly fee for "surface destruction" but it is NOTHING compared to te money they get from the oil. So, what I am referring to are these "groups" that thrive on the lack of knowledge of land buyers. They will buy a piece of property, sell the mineral rights, and then resell the land. Most people have no idea that they have agreed to purchase something that they won't have complete control over. No one who buys land is told they have something and actually don't. It is a strict law, but people don't understand te impact of not owning the mineral rights.