Directional Drilling

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2. DIRECTIONAL DRILLING
“Directional drilling is defined as an art and
science involving deflection of a well bore
in a specified direction in order to reach a
predetermined object below the surface of
the earth”.
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3. APPLICATIONS OF DIRECTIONAL DRILLING
1. Multiple wells from single location.
2. Inaccessible locations.
3. Drilling to avoid geological problems.
• Fault drilling.
• Salt dome drilling.
4. Side tracking and straightening.
5. Relief well drilling.
6. Controlling straight holes.
7. Horizontal well.
8. ERD well.
9. Multilateral drilling.
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4. NON PETROLEUM
APPLICATIONS
• Mining industry.
• Construction industry.
• Geo thermal engineering.
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5. MULTIPLE WELLS FROM SINGLE
LOCATION
Optimum number of wells can be drilled from
a single platform or artificial island. This
greatly simplifies gathering systems and
production techniques .
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7. INACCESSIBLE LOCATIONS
If reservoir located under river beds,
mountains, cities etc, this technique of
directional drilling is used .
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9. DRILLING TO AVOID GEOLOGICAL
PROBLEMS
A. FAULT DRILLING:
This eliminates the hazard of drilling a
vertical well through steeply inclined fault
plane which could slip and shear the
casing.
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11. B. SALT DOME DRILLING
To reach the producing formation which
often lie underneath the over hanging
cap of the dome, the well is first drilled at
one side of the dome and is then
deviated to producing zone to avoid
drilling problems such as large washouts,
lost circulation and corrosion .
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12. SALT DOME DRILLING
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13. SIDE TRACKING & STRAIGHTENING
It is used as remedial operation either to side
track obstruction by deviating the well bore
away from obstruction by deviating the well
bore back to vertical by straightening out
crooked holes.
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15. RELIEF WELL DRILLING
The technique is applied to the drilling of
relief wells so that mud may be pumped
into the reservoir of the uncontrolled well.
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17. ERD WELL
Advantages:
1.Increased horizontal displacement from
central platform.
2. Increased penetration length of reservoir.
3. Require less number of wells to develop a
field.
4. Require less number of platforms to
develop a field in offshore.
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18. ERD WELL
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21. HORIZONTAL WELL
Advantages:
1.Increasing the drainage area.
2.Prevention of gas coning or water coning
problems.
3.Increased penetration of the producing
formation.
4.Increasing the efficiency of enhanced oil
recovery ( EOR ).
5.Improving productivity in fractured
reservoirs by intersecting a numbers of
vertical fractures.
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22. HORIZONTAL WELL
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23. MUTILATERAL DRILLING
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25. Mutilateral. Drilling
Multilateral well has been defined as a well
that has more than one horizontal or near
horizontal laterals drilled from single site and
connected back to a single well bore.
Applications
. Greater reservoir exposure.
· Drain more than one reservoir.
· Exploit irregular reservoirs efficiently.
· Speed up reservoir drainage.
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26. Mutilateral. Drilling
· Reduction in drilling cost per unit length
of the well bore contacting, the reservoir
rock.
· Ability to obtain a given length of
horizontal well bore in reservoir where
drag would perhaps limit the length of
single horizontal well bore.
· Reduction in number of slots and thus
the number of production platforms.
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27. Reentering existing wells
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28. NON PETROLEUM APPLICATIONS
A. MINING INDUSTRY
- Directional wells are used to produce
methane gas that is contained in coal seams.
- Methane presents a safety hazard and must
be drained off before mining operations can
begin.
-In deep coal seams that are beyond the
reach of conventional mining techniques,
directional wells can be drilled for in situ
gasification projects.
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29. NON PETROLEUM APPLICATIONS
A. MINING INDUSTRY
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30. B. CONSTRUCTION INDUSTRY
• A small diameter pilot hole is drilled in a
smooth arc beneath the river until it
immerges on the other side. This acts as a
guide for the large diameter pipe forming
the conduit.
• The hole is drilled through soft sediments
about 40’ below the river bed. This
techniques has been used to cross rivers
up to 200’ wide.
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31. B. CONSTRUCTION INDUSTRY
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32. C.GEO THERMAL ENGINEERING
High geothermal gradient found in some
rocks( e.g. granite) can be harnessed to
provide energy.
Extracting the heat from this rocks requires
the drilling of injection and production
wells.
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33. C.GEO THERMAL ENGINEERING
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38. AZIMUTH
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39. AZIMUTH
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40. QUADRANTS
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41. QUADRANTS
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42. A radius of 100ft is commonly
used as target zone depending
on particular requirements e.g
a relief well requires much
smaller target in order to be
effective. Smaller the target,
greater number of correction
runs. So longer drilling time ,
high drilling costs. So the
target zone should be as large
as the geologist/reservoir
engineer can allow. DD’s job is
then to place the wellbore
within the target zone at
minimum cost
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44. TYPES OF WELL PROFILES
a. L- TYPE
b. S- TYPE
c. J- TYPE
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45. TYPE I (BUILD AND HOLD OR ‘L’ TYPE)
• This is the most common and simplest
profile for a directional well.
• The well is drilled down vertically to KOP,
where the well is deviated to required
inclination and further maintained to target.
• Shallow KOP selected to reduce inclination.
• This profile can be applied where large
displacements are required at relatively
shallow target depths.
• Under normal condition inclination should be
15 to 55°.
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47. TYPE II (BUILD HOLD AND DROP OR ‘S’
TYPE)
•This profile is similar to type-I up to tangential
section. Here the profile enters a drop of section
where inclination is reduced and in some cases
becomes vertical as it reaches the target.
•More torque and drag can be expected due to the
additional bend.
•Used where target is deep but horizontal
displacement is relatively small.
•It has also application when completing a well that
intersect multiple producing zones.
•Drilling of relief well where it is necessary to run
parallel to wild well
•Lease or target limitations.
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49. TYPE III (DEEP KICK OFF AND BUILD ‘J’
TYPE)
• Initial deflection is started well below the
surface and angle is built up to bottom.
• It is used in particular situations like salt dome
drilling, fault drilling and side- tracking or
repositioning of target.
• Disadvantages:
• Formation may be harder & less
responsive to deflection.
• More tripping time to change BHA while
deflecting.
• BUR is more difficult to control.
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53. HORIZONTAL WELL PROFILES
• HORIZONTAL WELLS ARE CATEGORIZED
BY THE RADIUS OF CURVATURE ADOPTED
TO MAKE THE WELL HORIZONTAL. THEY
ARE ALSO CLASSIFIED BY BUILD UP RATES
WHICH IS INVERSELY PROPORTIONAL TO
THE RADIUS OF CURVATURE:
– LONG RADIUS
– MEDIUM RADIUS
– SHORT RADIUS
– ULTRA SHORT RADIUS
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54. HORIZONTAL WELL TYPES
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55. BUILDUP SECTION BETWEEN 1°- 6°/100’ OR RADIUS LENGTH BETWEEN
1000’-5000’
• ADVANTAGES:-
– EASIER AS CONVENTIONAL DOWNHOLE HARDWARE IS USED
– PDM MAY NOT BE REQUIRED
– LOWER DOG - LEG SEVERITY GIVES LESS TORQUE AND DRAG
– LONGER LATERAL SECTIONS(3500’ TO 5000’) (1000M TO 1500M)
– EXTENDED REACH FROM SURFACE LOCATIONS
– ACCOMMODATES FULL LOGGING ALL COMPLETION METHODS
STIMULATION WORKOVER AND GASLIFT EQUIPMENT.
• DISADVANTAGES:-
– LONG RADIUS NECESSITATES BIGGER RIG, TOP DRIVE, LARGER
PUMPS AND GREATER MUD MANAGEMENT CAPABILITIES
– LONGER OPEN HOLE SECTIONS INCREASE RISK OF PIPE
STICKING ,KICKS AND BOREHOLE DAMAGE
– LESS PRECISE CONTROL OVER T.V.D
– LITTLE USE IN SMALL LEASES BECAUSE OF LONG
DISPLACEMENTS.
Long Radius
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56. HORIZONTAL WELL TYPES
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57. • BUILDUP SECTION BETWEEN 8°-20°/100’ OR RADIUS LENGTH
BETWEEN 716’ TO 286’(218M TO 87M)
– ADVANTAGES:-
• SUPERIOR IN PRECISION COMPARED TO LONG RADIUS
• ACCOMMODATION OF NORMAL/SMALL SIZE M.W.D
TOOLS
• ABLE TO DRILL LONG HORIZONTAL SECTION UPTO 5000’
– DISADVANTAGES:-
• TORQUE AND DRAG HIGHER THAN LONG RADIUS
• LIMITATION IN COMPLETION AND WORKOVER
OPERATIONS
Medium Radius
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58. HORIZONTAL WELL TYPES
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59. • Buildup section between 1°-3.5°/1’ and radius
length between 57’ to 16’
– Advantages:-
• Precise vertical placement of horizontal drain
• KOP below fluid contacts results less risk of poor
isolation
– Disadvantages:-
• Requires customized drilling equipment
• No control over bore hole azimuth (within 20°)
• Limited to open hole completion
• No coring and logging services
Short Radius
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60. HORIZONTAL WELL TYPES
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62. HORIZONTAL WELL TYPES
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63. DROPPING ROTARY ASSEMBLY
• Angle dropping principle is based on
pendulum principle
• Placing a stabilizer above the point of
tangency causes a reverse action and
the assembly becomes an angle
dropping assembly.
• The section of drill collars below the
stabilizer bends and sags downwards
due to pull of gravity, somewhat like the
action of a pendulum. so this assembly
is often called as pendulum assembly.

64. The stabilizer is normally placed 30’, 60’ or 90’
above the bit. As the distance increases, more
bend occurs and more drill collar weight forces
the bit to the lower side of the hole resulting in
increase of angle dropping rate.
Tentative guideline
30’: 0.25-.75°/100’
60’: 0.5-1.25°/100’
90’: 0.5-2.5°/100’
Variables for dropping rate
• Stiffer the drill collar, less the bending rate.
• More the drift angle in the well, greater the
dropping rate
• Higher the WOB, lesser the angle drop rate
• All the variables equal (drift angle, WOB etc.,
increase in rotary speed will result in increase in
angle drop.
The exact position of stabilizer depends on drill
collar size and weight, hole diameter, inclination
and WOB
The is adjusted with subs and pony drill collars
to increase or decrease the rate of drop

65. HOLDING ASSEMBLY:
• Packed hole assemblies are used when it is
necessary to keep angle and direction change to a
minimum
• In directional wells, packed hole assemblies are
used after the maximum drift angle is reached and it
is desired to maintain the angle.
• The stiff rigid assembly fits closely in the hole and is
held in place by multiple stabilizers.
• The stabilizers are normally placed at 0-10’-40’ or
0-10’-40-70’ above the bit.
• The rigidity and stiffness force the bha to remain in
the same relative position.
• Its efficiency increases by increasing stiffness and
rigidity

66. Given set of conditions determining hole size, d/collar size,
inclination, WOB, to lesser degree RPM , these two stabilizer
systems will have greater build tendency from 4 to 1.

67. Three stabilizer packed hole assemblies are designed to hold the bit on
course. These assemblies may build or drop gradually due to local conditions
and may be fine tuned by the use of under gauge stabilizers.