Drilling and producing the well 3

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

48

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

51

Applications of Directional Drilling

Drilling multiple wells from a single structure or pad

Most offshore development would not be possible without directional drilling

52

Applications of Directional Drilling

Steeply dipping

sands can be

drilled with a

single wellbore

53

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