When multiple wells are drilled from the same pad, it is often referred to as pad drilling. Often 6 or 8 horizontal wells stem from the same pad.
Typically the well pad drains an area that is rectangular known as a spacing unit, unit or pool--usually about one half mile wide by two miles long with the pad itself positioned at the center of the rectangle. The majority of the surface area in the rectangle is not required for the well pad and will be left completely undisturbed. The well pad generally consists of 4-5 acres that is cleared, leveled and surfaced over for siting the drilling rig, trucks and various other equipment required for drilling and completion activities.
The intent is to drill as many wells on a pad as are economically feasible. Drilling more wells on a pad helps to minimize the environmental footprint of drilling.