After selecting a site for an oil rig, scientists survey the area, determine its boundaries, and if necessary, conduct environmental impact studies. The oil company might need to sign lease agreements and titles to the land, and the legal jurisdiction of off-shore sites needs to be determined. After all these issues are settled, the land can be prepared. This is a time-consuming but necessary step in the oil-drilling process.
The crew clears and levels the land, and they build access roads, if necessary. They also drill a well if there is no natural water source nearby, since the drilling process requires water. To further prepare the area, they dig a reserve pit, which is used for the disposal of rocks and drilling mud. The pit is lined with plastic. If the site is ecologically sensitive (wilderness or marshland, for example), the rock cuttings and mud are trucked away and disposed of offsite, rather than being placed in a pit.
After preparing the land, the crew digs several holes. The first hole is a rectangular pit, or "cellar," around the spot where the actual drilling hole will go. This serves as a workspace for workers and their drilling equipment and accessories. The main hole has two portions. The larger, shallower portion is often drilled with a small truck rather than with the main rig, and it is then lined with a conductor pipe. Then the deeper main portion of the hole is drilled. Additional holes off to the side, which are used for temporary equipment storage, are also dug. Finally, the rig equipment is brought in by truck, barge or helicopter, depending on the drill site location.