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.
A wireline is an electric cable that is used to lower equipment or devices into a well and can transmit data back to the surface. A number of wireline tools can be lowered into a well in order to gather information; these include gamma ray, nuclear, and magnetic tools, among others. Wireline is usually wrapped around a large spool which can be placed on the back of a truck, or can be a permanent fixture on a rig. A wireline operator is responsible for operation and maintenance of the wireline truck and tools.