Drilling FluidsRemove cuttings

cool and clean bit

lubricate drill assembly

control formation pressure

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

Uses

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)

Drilling Fluids (Cont’d)

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

Casing

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- 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.

Conductor casing (30 - 36 inches)

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.

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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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.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

Wellhead are

selected according

to the maximum

anticipated surface

pressure.

Wellhead

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

Well Control Equipment:

Wellhead (Cont’d)

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.

Directional Drilling

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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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Applications of Directional Drilling

Inaccessible Locations

Drilling in towns,

from land to offshore

under production facilities

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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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Applications of Directional Drilling

Drilling multiple wells from a single structure or pad

Most offshore development would not be possible without directional drilling

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Applications of Directional Drilling

Steeply dipping

sands can be

drilled with a

single wellbore

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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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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

Directional Driling Types:

Vertical Type Slant (J) Type

“S” Type Horizontal Type

Directional Drilling