Page 9 - The Rotary Rig and Its Components

THE POWER SYSTEM

Petroleum Extension-The University of Texas at Austin

The Power System

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In this chapter:
• Power requirements of a rig

• Providing power to the components
• Transmitting power to the components
• Converting AC to DC

• Variability in the layout of a rig’s power system

n nearly every rig, the power required for drilling the well comes
Ofrom internal-combustion engines that are most often powered For more information on
by diesel fuel. A rig needs from two to four or even more engines, power systems, see these
titles from Unit I of the
depending on how deep the well is to be drilled. Big rigs typically Rotary Series:
have three or four 1,215-horsepower (906-kilowatt) engines with • Lesson 6: The Drawworks
1,200-kilovolt-ampere (kva) generators that together can generate and the Compound
4,860 horsepower (3,624 kilowatts). • Lesson 8: Diesel Engines
This horsepower or wattage is transmitted from the engines, or and Electric Power
prime movers (the basic source of rig power), to the rig components
through one of two types of drive—mechanical and electrical. On a
mechanical rig, parts such as chains and pulleys transmit engine power
to the components. Electric rigs sometimes require fewer of those
types of parts and transmit electric power from the prime movers
to electric motors at each component. Most new medium- to deep-
capacity rigs are electric because they are easier to rig up and maintain
than mechanical rigs are.
The power system uses the prime movers and the drives to produce
and transmit power to the hoisting, circulating, and rotating systems.
(The drilling systems are discussed in later sections of this book.)

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