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DRILLING
MIDDLE EAST TECHNICAL UNIVERSITY
Department of Petroleum and Natural Gas
Engineering
Dr. Mahmut Parlaktuna Res. Assist. Sevtaç Bülbül
Spring 2008
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PETROLEUM
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PETROLEUM

• a mixture of naturally occurring hydrocarbons
• may exist in the solid, liquid or gaseous
  states, depending upon the conditions of pressure
  and temperature
• When the chemical mixture is composed of
  molecules of small size gas at normal T
  P NATURAL GAS
• When larger molecules liquid at normal TP
  CRUDE OIL
• (Approximately 11-13wt hydrogen and 84-87 wt
  of carbon. Traces of oxygen, sulphur, nitrogen
  and helium maybe found as impurities in crude
  oil.)

In Pennsylvania,
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PETROLEUM

• Oil is formed in a source rock, along with water
  and gas.
• Over millions of years, the oil and gas float
  upwards along a migration path.

• If oil and gas does not rise to the surface, it
  collects in a reservoir a rock that has spaces
  where oil can collect. (e.g. Sandstone)
• There must also be a trap - a rock structure that
  forms an impermeable seal above and around the
  reservoir rock (e.g. clay and shale)

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DRILLING

• After an oil companys exploration geologists and
  geophysicists have obtained and analyzed the data
  from a prospective petroleum site,
• the landman has secured a lease,
• drilling permits and other preliminary papers are
  in order

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CABLE-TOOL DRILLING

• Repeatedly dropping a heavy metal bit into the
  ground, eventually breaking through rock and
  punching a hole through to the desired depth.
• The cuttings removed with a bailer, an open
  tube with a valve at the bottom.
• With todays technology, cable-tool drilling is
  almost not in use.

First oil well built in 1859 by Edwin L. Drake in
Pennsylvania
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ROTARY DRILLING

• Rotary drilling uses a sharp, rotating drill bit
  to drill the ground. As the hole gets deeper,
  pipes are added to the drill bit to allow it to
  go further.
• Most land rotary rigs are portable and moved to
  different drilling sites.
• Some offshore rotary rigs are mobile a boat tows
  the rig onto the drill site.
• Some offshore rigs are immobile they stay in
  the site throughout the life of the field.

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RIG COMPONENTS

• Power System
• Hoisting System
• Rotating System
• Circulating System

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POWER SYSTEM

• Provides the power to the entire rig.
• Diesel engines compose the majority of power
  sources on rotary rigs.
• Diesel engines drive large electric generators.
  The generators, in turn, produce electricity that
  is sent through cables to electric switch and
  control gear.

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HOISTING SYSTEM

• The hoisting system is used to raise and lower
  pipe in and out of the hole and to support the
  drill string to control the weight on the drill
  bit during drilling.
• The hoisting system consists of
• derrick,
• traveling and crown blocks,
• the drilling line
• the drawworks

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HOISTING SYSTEM

• The derrick is a steel tower that is used to
  support the traveling and crown blocks and the
  drill string.

• The drawworks is a big, heavy piece of
  machinery. It consists of a revolving drum around
  which the wire rope called drilling line is
  spooled or wrapped.

• The crown and traveling blocks are a set of
  pulleys that raise and lower the drill string.

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ROTATING SYSTEM

• The rotary system includes all the equipment
  used to achieve bit rotation.
• The main parts of the rotary system are
• Swivel
• Kelly
• Rotary drive
• Rotary table
• Drill pipe
• Drill collars

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ROTATING SYSTEM

• The swivel supports the weight of the drill
  string and permits rotation. The swivel is
  attached to the bottom of the traveling block and
  permits the drill string to rotate.

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ROTATING SYSTEM

• The kelly is the first section of pipe below the
  swivel. The outside cross section of the kelly is
  square or hexagonal to permit it to be gripped
  easily for turning.

• Torque is transmitted to the kelly through kelly
  bushings, which fit inside the master bushing of
  the rotary table.
• A kelly saver sub is used between the kelly and
  the first joint of drill pipe.

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ROTATING SYSTEM

• As the rotary table turns the kelly is also
  turned. The movement of the kelly rotates the
  drill string and the drill bit.
• The major portion of the drill string is composed
  of drill pipe. Drill pipe is round steel tubes
  about 30 feet long with a diameter of from 4 to 5
  inches.
• The lower section of the rotary drill string is
  composed of drill collars. The drill collars are
  thick-walled heavy steel tubulars used to apply
  weight to the bit and prevent buckling of the
  drillpipes.

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ROTATING SYSTEM

• The process of drilling a hole in the ground
  requires the use of drilling bits.
• Rotary drilling bits usually are classified
  according to their design as
• Drag bits Fixed cutter blades, rotate as a unit
  with the drill string.
• Rolling cutter bits Usually three cones that are
  free to turn as bit rotates.

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CIRCULATING SYSTEM

• Circulating system circulates drilling fluid.
• The drilling fluid is most commonly a suspension
  of clay and other materials in water and is
  called drilling mud. Drilling mud removes
  cuttings from the hole and cools and lubricates
  the drilling bit.
• The principal components of the circulating
  system include
• Mud pumps and mud pits
• Mud-mixing equipment
• Contaminant-removal equipment

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CIRCULATING SYSTEM

• The drilling mud travels
• Steel tanks
• Mud pump
• Drill string
• Bit
• Annular space btw drill string hole to
  the surface
• Contaminant-removal equip.
• Back to the suction tank.

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CIRCULATING SYSTEM

• The mud pump takes in mud from the mud pits and
  sends it out a discharge line to a standpipe.
• The standpipe is a steel pipe mounted vertically
  on one leg of the mast or derrick.
• The mud is pumped up the standpipe and into a
  flexible, very strong, reinforced rubber hose
  called the rotary hose or kelly hose. The rotary
  hose is connected to the swivel.
• The mud enters the swivel, goes down the kelly,
  drill pipe and drill collars and the bit. It then
  does a sharp U-turn and heads back up the hole in
  the annulus.

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CIRCULATING SYSTEM

• Finally the mud leaves the hole through a steel
  pipe called the mud return line and falls over a
  vibrating, screen like device called the shale
  shaker.
• Agitators installed on the mud pits help maintain
  a uniform mixture of liquids and solids in the
  mud.
• If any fine silt or sand is being drilled, then
  devices called desilters or desanders may be
  added.
• If there are small amounts of gas in the
  formation, a device called degasser is also
  added.

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• DRILLING IS A COMPLEX OPERATION THAT INCLUDES
  MANY DIFFERENT PROCESSES, TECHNOLOGIES AND
  DISCIPLINES.

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THANKS FOR LISTENING.