Basic introduction to directional drilling and its applications including deviated well patterns

1. Directional Drilling 1
Introduction to Directional
Drilling and its Applications

2. Directional Drilling 2
Company: Sokono Engineering Servives
Facilitator: O. N. Ogbon

3. Directional Drilling 3
Main Topics
What is Directional Drilling
Directional Drilling Applications
Deviated Well Patterns(Profiles)

4. Directional Drilling 4
What is Directional Drilling

5. Directional Drilling 5
What is Directional Drilling?
Definition
The Science/Technology of DIRECTIONALLY DEVIATING a
Well From a VERTICAL POSITION Under the Rotary Table
Along a PLANNED COURSE to a SUBTARREAN TARGET
Located at a Given HORIZONTAL DISTANCE From the
Point of Drilling.

6. Directional Drilling 6
Directional Drilling Applications

7. Directional Drilling
Directional Drilling Applications
Directional drilling is applied mostly in
 Drilling requiring high azimuthal turn to avoid structural
impediment.
 River crossing
 Radial drilling requiring inclination exceeding 900
 Maximum production from structurally restricted reservoirs
such as:
 Fractured reservoirs
 Cavernous reservoirs

8. Directional Drilling 8
Directional Drilling Applications
Multiwells Drilled From Artificial Island Drilling From Shoreline to Target
Offshore Waters

9. Directional Drilling 9
Directional Drilling Applications
 Relief Well For Blow-out Control
 Fault Control Drilling
 Single Well For Multiple Targets
 Avoiding Impediment Directly Above Reservoir Or
Where Environmental Concerns Restrict Rig
Location

10. Directional Drilling 10
Directional Drilling Applications
 Compensating For Geological Tendencies
 Correction/Sidetrack Drilling
Salt Dome Drilling
Drilling to Locate
Oil/Water Contact
Intended Course
Intended Course
Intended Course
Intended Course

11. Directional Drilling 11
Directional Drilling Applications
 Horizontal Drilling
Definition:
Directional drilling whereby inclination is built progressively from 00 to 900 
(horizontally)

12. Directional Drilling 12
Directional Drilling Applications
 Horizontal Drilling
Definition:
 Reservoirs with oil zone sandwiched between aquifer and overlaying gas
cap
 Reservoir with gas and water coning problems
 Reservoirs with oil circulating vertical fractures
 Reservoirs with thin productive zones
 Reservoirs with thick productive zone of marginal permeability
 Reservoirs with thick and heavy oil requiring enhanced oil recovery
project.
 Old reservoirs with inadequate drive mechanism.

13. Directional Drilling 13
Directional Drilling Applications
 Multibranch Drilling
 Definition:
Directional well with a single trunk connecting two or more wells of
any trajectory

14. Directional Drilling 14
Directional Drilling Applications
 Multibranch Drilling
 Different Concepts of Multibranch
Horizontal Lateral to
Drain Lower Section
High Angle Lateral
Cutting Across
Entire Upper Section
Level 4 Junction
Horizontal Lateral to
Drain Lower Section
High Angle Lateral
Cutting Across
Entire Upper Section
Level 4 Junction

15. Directional Drilling 15
Directional Drilling Applications
 Multilateral Drilling
Definition:
Directional well with a single trunk connecting two or more horizontal or
high angle ( 800 ) wells
 Note:
A Multilateral Well is a Multibranch Well
But
All Multibranch Wells are Not Multilaterals

16. Directional Drilling 16
Deviated Well Patterns

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Deviated Well Patterns
 Factors Guiding Choice Pattern
 Target spacing
 Geological structures
 Formation competence/casing programme
 Pattern Types
 Shallow K/O & Maintain Course To Target (Type I)

18. Directional Drilling 18
Deviated Well Patterns
 Pattern Types
Shallow K/O & Maintain Course To Target (Type I)
 Characteristics of Shallow K/O
 Less tension
 Less torque
 Less fatigue stress in drill pipe
 Less risk of key seating
 Less risk of stuck pipe
 Less cost due to less trips
 Susceptible to hole instability
 Convenient surface casing

19. Directional Drilling 19
Deviated Well Patterns
 Pattern Types
Shallow K/O & Maintain Course To Target (Type I)
 Applications:
 Deep wells with large horizontal
displacement
 Moderately deep wells with moderate
horizontal displacement.
 High inclination wells

20. Directional Drilling 20
Deviated Well Patterns
 Pattern Types
 Deep K/O & Maintain Course To Target

21. Directional Drilling 21
Deviated Well Patterns
 Pattern Types
 Deep K/O & Maintain Course To Target
 Characteristics
 Tool face orientation difficult to achieve.
 BHA changes require longer time to achieve.
 Initial kick-off is always difficult to achieve due to harder
formation at deeper depths.
 Applications:
 Appraisal wells to access extent of new reservoir.
 Salt dome drilling.
 Re-drilling or repositioning of hole bottom.
 Deep wells with short horizontal displacement.

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Deviated Well Patterns
 S – Shape
Characteristics and Problems
Drag
Torque
Fatigue/stress in drill pipes
Risk of keyseating
Logging due to high inclination
and curvature.

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Deviated Well Patterns
 S – Shape
 Applications:
 Access to multiple pay zones
 Offers reduced final angle of inclination
into reservoir giving rise to easier
completion.
 Good where there is lease and/or target
limitation
 Assists in well spacing requirements in
 Multi-well field.
 Deep wells with small displacement.

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Deviated Well Patterns
 Horizontal Patterns  Extended Reach
 Medium Radius
 Long Radius With Horizontal Section
 Inverted Long Radius
 S-Shape
S-Shape
Inverted
Long
R
adius
Long
R
adius
w
ith
H
orizontal Section
Extended Reach
Medium Radius
S-Shape
Inverted
Long
R
adius
Long
R
adius
w
ith
H
orizontal Section
Extended Reach
S-Shape
Inverted
Long
R
adius
Long
R
adius
w
ith
H
orizontal Section
Extended Reach
Medium Radius