Page 13 - A Primer of Oilwell Drilling, 7th Edition

he main function of a rotary rig is to drill a hole in the ground,
Tor to make hole. Making hole with a rotary rig requires quali- 9
Petroleum Extension-The University of Texas at Austin
fied personnel and a large amount of equipment. There are four
main categories of equipment systems used in making hole: power,
hoisting, rotating, and circulating.

POWER SySTEM Rig
Every rig needs a source of power to run the hoisting, circulating, Components
and rotating equipment. in the early days of drilling, steam engines
powered most rigs. in the 1860s, Colonel Drake powered his rig
with a wood-fired steamboat engine. Until the 1940s and 50s, steam
engines drove almost every rig (fig. 95).
Steam is a tremendous power source. For example, steam cata-
pults are used today on modern aircraft carriers to launch aircraft.
The major problem with using steam power on drilling rigs was that
the boilers were heavy and difficult to move. Also, the steam lines
to the steam engines were heavy and withstood high pressures and
temperatures. Steam power also required large volumes of water
and fuel.

Figure 95. In the foreground is a coal-fred boiler that made steam to
power the cable-tool rig in the background.

93