RE: Amount3 Mar 2020 11:11
Initially, when a new oil well is going to be drilled, a larger drill bit is used than what is going to be used to get to the final depth. This first drill clears out dirt, rock, and other debris and creates a hole in the surface that is then lined with concrete, forming a barrier to avoid any contaminants from bleeding into the groundwater.
Once the initial hole is complete, the main drill bit is attached. The day the main drill bit begins drilling into the ground—a process called spudding in—is referred to as the "spud date." In cases of offshore oil rigs, the spud date occurs when the drill begins working on the seafloor, not when it first breaches the water.