introduction to directional drilling

8.1. Introduction to Directional Drilling
1/39Quartz School. Module 8: Directional Drilling / Section 1C. Alvarez
SectionSection –– 11
Introduction to DDIntroduction to DD
Quartz School for Well Site SupervisorsQuartz School for Well Site SupervisorsQuartz School for Well Site SupervisorsQuartz School for Well Site SupervisorsQuartz School for Well Site SupervisorsQuartz School for Well Site SupervisorsQuartz School for Well Site SupervisorsQuartz School for Well Site Supervisors
ModuleModule –– 88
Directional DrillingDirectional Drilling

Definition of Directional DrillingDefinition of Directional DrillingDefinition of Directional DrillingDefinition of Directional Drilling
DD is the operational procedure
followed for planning and deviating a
well bore along the planned course to
a subsurface target whose location is
at a given lateral distance, vertical
depth and direction from the origin at
surface.

Applications of Directional Drilling

Directional Drilling Applications
Inaccessible LocationsInaccessible LocationsInaccessible LocationsInaccessible Locations
Salt Dome DrillingSalt Dome DrillingSalt Dome DrillingSalt Dome Drilling Fault ControllingFault ControllingFault ControllingFault Controlling
SidetracksSidetracksSidetracksSidetracks

Relief WellsRelief WellsRelief WellsRelief Wells PlatformPlatformPlatformPlatform ---- OffshoreOffshoreOffshoreOffshore
DrainageDrainageDrainageDrainage MultilateralsMultilateralsMultilateralsMultilaterals
Directional Drilling Applications

- the late 1920’s
1st application of oil well surveying using the acid bottle
inclinometer
- 1929
Directional inclinometer with magnetic needle.
- the 1930’s
1st controlled directional well drilled
(initially for unethical purposes, to cross property lines)
- 1934
Controlled DD was used to kill a wild well.
Beginning of controlled DD
Historical Background

< 1950 Magnetic Single Shot
(survey after drilling)
Significant Events:
1960’s Mud Motor
(versatile kick off tool)
1970’s Steering Tool
(survey while drilling)
1980 MWD
(mud pulse telemetry - no wireline)
1980’s Steerable Motor
1980’s LWD
(log quality Data)
1988 Horizontal Drilling
(drilling for drainage)
1990’s GeoSteering
(geologic vs geometric steering)
1999 Rotary Steerable Drilling
200? Better Measurements/Data Rates, Multi-Laterals?……….?

Well Bore Deviation Methods

Well Deviation with Rotary Assemblies
All BHAs cause a side force at the bit, leading to
change hole inclination
Fulcrum Effect: Builds Inclination
Packed Effect: Holds Inclination
Pendulum Effect: Drops Inclination
Positive side force-Build Inc.
Zero Net Side force-Hold Inc.
Negative Side force-Drop Inc.

Three factors affecting bit side force are:
Mechanical characteristics of the BHA
The gauge and placement of stabilizers and other BHA
components
The diameter, length and material of the BHA
components
Bit type
Drilling parameters applied to the BHA
Weight on bit
Rotary Speed
Circulation or flow rate
Formation being drilled

Weight on Bit
With WOB we can induce Bit Tilt by
moving the tangent closer to the bit and
thus generate a Build Force (positive
side force).
If the Build Force is great enough it will
become greater than the pendulum force
and an increase in hole angle will result.
Bit Tilt
Hole Direction
Positive Side Force

Forces acting on a bit in an inclined hole
Side force with zero WOB
Negative bit side Force

Build Hold Drop Drop
Stabilizer Placement and resultant side forces

Well Bore Deviation by Jetting
• Used in soft formations
• One large bit nozzle oriented to the desired direction
• Near Bit Stabilizer and limber assembly
• Wash a “pocket” in the formation
• Spud and rotate, wash, until angle is built
• Continue building with rotary BHA
• Azimuth corrections more difficult with > inclination

Well Bore Deviation with Open Hole Whipstock
• Used in medium to hard formations
• Bit, NB Stab. pinned to whip and conveyed to bottom
• Tool Face oriented
• Whip is wedged on bottom and pin sheared
• Undersized pilot hole is drilled
• Only one joint drilled before POOH the BHA
• Pilot hole opened up and process repeated

Well Bore Deviation with Dynadrill in early 60’s
• First commercial PDM
• Hydraulic power to Mech. power driving the Bit
• String kept stationary - only sliding
• Bent sub above motor provides side force to the bit
• Deflects the hole trajectory - kick-off from vertical,
sidetrack, correction run, etc.
• Very efficient when compared to contemporary
deflection devices, (jetting, whipstocks ..)

Well Bore Deviation with Steerable Motors in Late 80’s
• Bend closer to the bit reduces bit
offset for equivalent curvature.
< bit offset = < component stress
-Rotation possible without concern
for component failure.
• After kick-off, drill tangents, adjust
trajectory without POOH.
-Bit walk and build/drop tendencies
not always predictable with rotary
BHA’s.
• Efficiency achieved with motor bits,
multi-lobe power sections and
wireless MWD.
Bent Sub
Early 60’s
Steerable
Motor
Late 80’s

• Top Sub crosses over from Stator to drillstring. (also
dump valve, flexed sub…..)
• Power Section - Rotor/Stator
• Transmission shaft transforms eccentric rotation to
concentric rotation.
• Bearing assembly
• Drive Sub
PDM - Basic Components
Well Bore Deviation with Steerable Motors in Late 80’s

Well Bore Deviation with Steerable Motors – SLB PowerPack Motor
• 89 models from 2 1/8 in. to 11 1/4 in.
• PowerPak XP & GT extended power sections
• PowerPak XF & XC short radius drilling
• Oil seal or mud lubricated bearings

SLB PowerPak Fleet performance ranges
90 ft.lbs - 1550 ft.lbs
Size Range - 2 1/8” - 11 1/4”
Hole Size - 2 3/8” - 26”
Lengths - 8.4’ - 32.02’
Flow Range - 20 gpm - 1700 gpm
Bit Speed - 45 rpm - 640 rpm
Power Output - 6.5 hp - 750 hp
Torque Range -
Well Bore Deviation with Steerable Motors

• Hydraulic power to Mechanical for powering the Bit.
• Versatility - flexible components, sensors added, variety of formations &
conditions.
• Short & Medium radius curves possible
• Reduction in:
–BHA component weight.
–String rotation.
–Casing wear.
–String vibration.
• Issues:
–Hole tortuosity.
–Bit life, matching bits to motor/formation
–Slide drilling
–Stator strength (length & BHA response)
Well Bore Deviation with Steerable Motors

Well Bore Deviation with Rotary Steering Systems
(Last Generation of DD Tools developed in Late 90’s and 00’s)

• Types of Rotary Steering Systems:
• Point the Bit System
• Uses one non rotating sleeve which performs geo stationary reference.
• The motor axis is deflected while rotates.
• The bit is so displaced laterally from its central axis, pointing in the desired
direction.
• Push the Bit System
• Uses one non rotating sleeve with retractable pads
• When a pad is out contact the wall of well bore and pushes the bit in the
opposite direction.
Well Bore Deviation with Rotary Steering Systems

Baker Hughes Inteq Rotary Steering System
• AutoTrak
• Push the bit System
• Requires continuous lateral
contact with well bore
4.0m
(13.2 ft)
Inclinatio n
0.9m
(3.0ft)
Resistivity
11.2m
(36.8 ft)
5.6m
(18.4 ft)
5.4m
(17.7 ft)
V ibration
Gam m a ray
5.0m
(16.4 ft)
6.6m
(21.7 ft)

Halliburton Rotary Steering System
• GeoPilot
• Point the bit System
• Requires lateral contact with well
bore
• Non rotating external component
•At-Bit Inclination 3 ft w/ azimuthal gamma ray
•Outer housing rotates slowly
•Anti-rotation wheels limit rotation
•Maximum DLS reduced with redesign

Precision Drilling Rotary Steering System –Revolution (Point the Bit)
Deflects shaft with universal joint at each end toDeflects shaft with universal joint at each end toDeflects shaft with universal joint at each end toDeflects shaft with universal joint at each end to
Lie to one side of non rotating housingLie to one side of non rotating housingLie to one side of non rotating housingLie to one side of non rotating housing
Non Rotating SleeveNon Rotating SleeveNon Rotating SleeveNon Rotating Sleeve
Neutral ModeNeutral ModeNeutral ModeNeutral Mode
Drill HoldingDrill HoldingDrill HoldingDrill Holding
AngleAngleAngleAngle
DirectionalDirectionalDirectionalDirectional
Mode DeviateMode DeviateMode DeviateMode Deviate
holeholeholehole
AxisAxisAxisAxis
deflection bydeflection bydeflection bydeflection by
72 pistons72 pistons72 pistons72 pistons
Pistons locatedPistons locatedPistons locatedPistons located
underneath the NRSunderneath the NRSunderneath the NRSunderneath the NRS

GyroData Rotary Steering System
20 feet long non rotating section20 feet long non rotating section20 feet long non rotating section20 feet long non rotating section
Centralizer Mechanism ActivateCentralizer Mechanism ActivateCentralizer Mechanism ActivateCentralizer Mechanism Activate
6 3/46 3/46 3/46 3/4”””” Tool Size availableTool Size availableTool Size availableTool Size available
WellGuide – Point the Bit System

100% Rotational Steering Systems

Schlumberger Rotary Steering Systems
• Power Drive Xtra
• “Push the Bit” system
• Power “V”
• Automatic “Push the Bit” system
• No Downlink required
• Power Drive Xceed
• “Point the Bit” system
• Power Drive Vortex
• Power Drive plus Down Hole
Motor to increase bit rpm for
Performance Drilling applications
All Rotational Tools – No stationary components

Power Drive Xtra • Directional tool that allows changes
in direction and inclination of well
bore performing directional control in
2 or 3 dimensions while the drilling
string is continuously in rotational
mode
• All PD components rotate with the
drill string
• Directional control is performed in
real time from surface by sending
commands in form of flow rate
variations to make adjusts both in
direction and inclination
• NO SLIDING IS REQUIRED!!!

PowerDrive = Schlumberger RSS
• A 3-D fully Steerable tool capable
of changing both the inclination
and azimuth of the well bore while
maintaining continuous drill string
rotation
• All external components rotate with
string RPM (Schlumberger only)

Power Drive Xtra – Steering Principle
• Apply side force to the bit to initiate a side cutting action
• Pads extend dynamically from the rotating housing (bias unit)
• TF controlled by orientation of internal valve assembly
• Defines at which point during its rotation that a pad will actuate
• Dogleg is controlled by alternating between non-rotary and rotary control
of the valve assembly relative to space

PowerDrive BHA – Controlling Factors
Control variables
• Bit characteristics
• Stabilizer gauge
• Mud Hydraulics*
• Flex characteristics

PD Xceed ™ Rotary Steerable System

Push the Bit / Point the Bit Differences

introduction to directional drilling

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