Drilling Rig Rotary Table Sizes

Land drilling rigs can be classified according to the drilling depth into different sizes
Light duty rigs: drill holes from about (3000-5000 ft) deep or (1000-1500 meters
Medium duty rigs: drill to depth ranging from (4000-10000 ft) or (1200-3000 meters
Heavy duty rigs: drill holes from about (12000-16000 ft) deep or (3500-5000 meters
Ultraheavy duty rigs: drill holes from about (18000-25000 ft) deep or (5500-7500 meters
Drilling Rig Rotary Table Sizes


The main function of a rotary rig is to drill a hole, or as it is known in the industry, to make hole
Making hole with a rotary rig requires not only qualified personnel, but a lot of equipment as well
In order to learn about the components that it takes to make hole, it is convenient to divide them
into  a  number  of  main  systems:  power,  hoisting,  rotating,  circulating,  well  control,  and  well
monitoring  system.  Various  components  comprise  the  systems,  but  all  require  power  to  make
them work


Most rig power is consumed by hoisting and fluid circulating systems. The other rig systems have
much smaller power requirements. Fortunately, the hoisting and circulating systems generally are
not used simultaneously, so that the same engines perform both functions

Total  power  requirements  for  most  rigs  are  from  1000  to  3000  hp provided  by  one  or  more
engines depending on well depth and rig design. Power requirements vary for different drilling
jobs, shallow or moderate depth drilling rigs need 500 - 1,000 HP, heavy-duty rigs for 20,000 foot
(6000 meters) holes usually need 3,000 hp, Auxiliary power requirements for lighting, etc., may
be 100 - 500 hp
The  early  drilling  rigs  were  powered  primarily  by  steam.  However,  because  of  high  fuel
consumption and lack of portability of the large boiler plants required, steam-powered rigs have
become  impractical.  Modern  rigs  are  powered  by  internal-combustion  diesel  (or  gas)  engines
.engines and sub-classified depending on the method used to transmit power to the various rig

Diesel electric type
Direct drive type

Diesel  electric  rigs  are  those  in  which  the  main  rig  engines  are  used  to  generate  electricity
Electric power  is transmitted  easily to the  various  rig systems(the diesel  engines generate  and
deliver  electric  power  by  cables  to  electrical  then  to  electric  motors  attached  to  the  involved
equipments) switch gear then to , where the required work is accomplished through use of electric
motors. Direct-current motors can be wired to give a wide range of speed-torque characteristics
That are extremely well-suited for the hoisting and circulating operations. The rig components
can be packaged as portable units that can be connected with plug-in electric cable connectors

There is considerable  flexibility of  equipment placement, allowing better space  utilization and
weight distribution. In addition, electric power allows the use of relatively simple and flexible
control system. The driller can apply power smoothly to various rig components, thus minimizing
shock and vibration problems

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Direct  drive  rigs  accomplish  power  transmission  from  the  internal-combustion  engines  using
system of pulleys, gears, chains, belts, and clutches rather than generators and motors. The initial
cost  of  a  direct-drive  power  system  generally  is  considerably  less  than  that  of  a  comparable
diesel-electric  power  system.  The  development  of  hydraulic  drive  has  improved  greatly  the
performance  of  this  type  of  power  system.  Hydraulic  drives  reduce  shock  and  vibrational
problems  of  the  direct  drive  power  system.  Torque  convertors,  which  are  hydraulic  drives
designed so that the output torque increases rapidly with output load, are now used to extend the
speed-torque characteristics of the internal-combustion engine over greater ranges that are better
suited  to  drilling  applications.  The  use  of  torque  convertors also  allows  selection  of  engines
based   on   running   conditions   rather   than   starting   conditions.   Power-system   performance
characteristics generally are stated in terms of output horsepower, torque and fuel consumption
for various engine speeds
3000hp =2237099.615 watt equal to the power operates 22371 house lamps.
The power on modern rigs is most commonly generated by diesel-electric power units. The power
produced is AC current which is then converted to DC current by the use of SCR (Silicon
Controlled Rectifier

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