Spud the Well:
After the rig has been inspected and all of the systems tested the well can be Spudded. Spudding a Well refers to starting the rotary drilling operations for that well.

Drill Down to the Surface Casing Depth:
The first section of the well to be drilled is the section that goes down to the pre-determined surface casing depth (Casing Point). Obviously, for this section of the wellbore, the drill bit diameter must be smaller than the ID (inner diameter) of the conductor casing. In this shallow section of the wellbore, fresh water aquifers (both for personal and municipal use) exist. As discussed earlier, shallow gas hazards may also exit.

The objectives of drilling this first section of the well is to allow the setting and cementing of the surface casing to:
Protect the fresh water aquifers by placing a steel and concrete barrier to isolate the water table from the well;
Protect the well from the aquifer (cutting of the drilling fluids with fresh water);
Protect the well from shallow gas hazards.

This section of the well is drilled through the most environmentally sensitive depths. Consequently, when this section of the hole is drilled, it is typically drilled with the most environmentally friendly drilling fluid (possibly either air or fresh water) and cased and cemented as soon as possible to alleviate any potential of contaminating fresh water aquifers. By running the surface casing string, we are putting the environmentally sensitive water table behind pipe and protecting it from future well (drilling and production) activities.