1. Drilling Fluids
Remove cuttings
cool and clean bit
lubricate drill assembly
control formation pressure Uses
maintain wellbore stability
prevent lost circulation
Types of Drilling Fluids
• Water-based muds
–Most common and least costly
–Bentonite, dispersants, and NaOH added
• Oil-based mud;
• Air drilling <1000 psi, 500-800 cfm
-Dry air
-Misting
-Foam
2. Drilling Fluids (Cont’d)
Determination of Mud Prop.
– Mud Density
– Viscosity (YP – PV) and gel
– Water Loss (cc/30 dk)
– Ph
– Solids Content
– Salt Content
– Alkalanity(pf, Mf, -CO3 ve HCO3)
3. Casing
Casing:
– Prevents the hole from collapsing
– Provides the means to drill deeper
– Prevent the contamination of the fresh water
table
– Provide the control of subsurface pressures
– Prevent the mixture of the production fluids
4. Conductor casing (30 - 36 inches)
- Conductor casing’s function is to prevent caving in
- The conductor hole has to start up very big because
the hole diameter decreases.
- The conductor casing will be hammered if the
ground near the surface is really soft until reaching
refusal point.
- If the ground near surface is hard it must be drilled
for the casing to run in.
- If the conductor hole is drilled the casing is
cemented in it.
- Use the bit whose diameter is smaller to easily go
inside conductor casing.
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5. Casing
Casing: Surface casing (20
inches)
- Hole of surface casing is
26 inches.
- Surface casing’s
function is to protect from
fresh water zone.
- Bop stack is attached to
surface casing.
- Depth of surface hole set
by regulatory agencies.
6. Intermediate casing (13 3/8 inches)
- Hole of intermediate casing is 17 1/2 inches.
- Intermediate casing’s function is to seal off
trouble zones.
- Intermediate casing is also cemented in the
place to seal off trouble formations like lost
circulation zones.
- Intermediate is the largest section of casing in
the well and is connecting to bop stack.
- If there are more than one intermediate
casing, the hole size for another intermediate
casing is 12 1/2 and casing size is 9 5/8.
Production casing (7 inches)
- Hole of production casing is 8 1/2 inches.
- Production casing function is to isolate the
producing zone and to protect well completion
equipment like perforation.
- It’s the last casing which is used in protecting
the producing zone.
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7. .Liner casing
-Liner is a short section in casing string
which is used to case small open hole
sections below an existing casing string in
a hole and it does not run all the way to
surface.
- Liner hanger: that’s used to connect
liner string with a previously running
casing.
-Using liner saves money which it's
doesn’t require to be extended from the
surface
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8. Wellhead
Wellhead are
selected according
to the maximum
anticipated surface
pressure.
9. Wellhead (Cont’d)
Well Control Equipment:
BOP (Blow Out Preventer):
• Annular Type
• Ram Type (Blind, Shear or Pipe
Ram)
• Inside BOP, Kelly Cock
• Separators
• Choke and Choke Manifoldu
• Closing Unit ve Remote Control
Panel
10. Directional Drilling
Directional Drilling:
Directional drilling is a type of
drilling, which is intentional
deviation of the well from
vertical.
Directional drilling campaigns are
drilling the well to the pre-
determined target(s).
It is important to take into
consideration all means in a 3-D
manner.
11. Applications of Directional Drilling
One of the
primary uses of
directional drilling
was to sidetrack a
well even if it was
to go around a
stuck BHA
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12. Applications of Directional Drilling
Inaccessible
Locations
Drilling in towns,
from land to offshore
under production
facilities
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13. Applications of Directional Drilling
Salt Dome Drilling
Salt can cause
significant drilling
problems and
directional drilling can
be used to drill under
the overhanging cap
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14. Applications of Directional Drilling
Drillingmultiple
wells from a
single structure or
pad
Most offshore
development
would not be
possible without
directional drilling
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16. Applications of Directional Drilling
Fault drilling
In hard rock, deviation
can be a problem
Sometimes the bit can
track a fault
Drilling at a higher
incident angle
minimizes the potential
for deflection of the bit
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17. Applications of Directional Drilling
Relief well drilling
Directional drilling
into the blowout
when the surface
location is no longer
accessible
Very small target
and takes
specialized
equipment
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