This document provides an introduction to directional drilling and its applications. It defines directional drilling as deviating a well from vertical to a planned subsurface target. Directional drilling is mostly used to avoid structural impediments, for river crossings, high angle wells, and maximizing production from structurally restricted reservoirs like fractured or cavernous reservoirs. Applications include multi-well drilling from artificial islands or shorelines, relief wells, fault control drilling, and horizontal drilling. Deviated well patterns include shallow and deep kick-offs, S-shapes, and horizontal patterns like extended reach and various radius wells.

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

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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.

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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

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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)

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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

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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