A mineral lease is an agreement by which a producer is given the right to drill your land to develop and extract the minerals underneath. If drilling is successful, you will receive a small portion of the profits from the sale of hydrocarbons from your lands. The amount paid to you will decline over time as minerals are extracted.
Selling mineral rights allows you to be paid cash up front for 100% of the anticipated value of the minerals that could be extracted from under your land. This value is paid directly to you in a lump sum payment and does not require any drilling of your property.