As home to supermajors, as well as a plethora of smaller, independent energy players, the US boasts one of the largest concentrations of energy personnel in the world. With its insatiable appetite for energy resources, the United States is the world's single largest consumer of oil, using as much as 20.73 million barrels per day as of 2008. Recently, interest has peaked in the vast quantity of untapped natural gas resources in the US, the reserves of which were inventoried in 2008 at 238 Tcf, with producers specifically targeting the nation's promising shale formations for this energy commodity.
Drilling fluids, also referred to as drilling mud, are added to the wellbore to facilitate the drilling process by suspending cuttings, controlling pressure, stabilizing exposed rock, providing buoyancy, and cooling the drill bit. Mud engineers ensure that the drilling mud that is used is made to the required specifications based on the expected geology. Drilling fluids can be water, oil, or synthetic-based, and mud engineers must take rock formation composition, as well as environmental impact, into account when making decisions about what drilling fluids might be best for any given well.