Basic questions. 1. Does my property/mineral rights have to be above a gas deposit in order to become eligible for royalties? 2. Does the Operator know the physical size of a gas deposit they are drilling?
All wells are assigned a spacing unit when drilled. The size of the unit is set by the regulatory agency of whatever State you are in and takes into account the type of reservoir, the depth, oil vs gas, and other factors. All the mineral owners within the designated unit will receive a share of the royalties.
You are eligible for royalty from oil & gas wells that are producing from a unit of which your minerals are a part. Geologists have a basic idea of the extent of the reservoir.