Rotary drilling machine, also known as pile driver. It is a comprehensive drilling rig, for its usage of a variety of bottom layers, the characteristics of fast forming layers, less pollution, and strong mobility.
[pdf] NOV's two main predecessors, Oilwell Supply and National Supply, were founded in 1862 and 1893, respectively. These two companies manufactured and distributed pumps and derricks. In 1930, acquired Oilwell Supply. In 1958, merged with National Supply. In 1987, National Supply merged with USS Oilwell to become "National Oilwell". Varco was founded as Abegg and Reinhold Company by Walter Abegg and Baldwin Reinhold i.
[pdf] Now, after years of rig market doldrums and rig fleet contraction, the market is experiencing the beginnings of a revival, with rising rates and dwindling availability. In the immediate aftermath of Russia’.
[pdf] 
