While the primary function of an oil rig is to drill for oil, there are a number of supporting roles that are essential for the comfort, convenience and support of the rig crew. While these do not all require a strong orientation toward mechanics or engineering, they are nevertheless integral to the success of the expedition. In addition, many individuals start out their careers in one of these supporting roles, just to gain some experience of working on a rig. After a couple of shifts in such a function, they are able to use their contacts to get into the mainstream roles. Some of the supporting roles are: