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Directional Drilling presentation

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In the name of Allah An Introduction to Directional Drilling (Advanced Drilling Engineering course)

Instructor: Dr. Tabatabaei nejad Lecturer: Mojtaba Owrangi - 87333102 Master of Petroleum Drilling & Production engineering Sahand University of Technology

Introduction 1. 2. 3. 4. 5. 6. 7.

Definition & Reasons for D.D Reference Systems and Coordinates Types of Directional well trajectories Calculation of a well trajectory Directional Drilling Measurements Deflection Tools Principles of BHA Directional Drilling presentation

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Definition & Reasons for D.D z Definition : z

The science of directing a well bore along a predetermined trajectory to intersect a designated subsurface target.

z Kick off point (KOP): z

The kick off point is defined as the point below surface location where the well is deflected from the vertical.

z Target: Target z

A predetermined point in the reservoir that D.D should reaches to it. Directional Drilling presentation

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Well classification Vertical Well

Wells with less than 10º deviation

High Inclination Well Horizontal Well

Wells between 60 and 85º deviation

Extended Reach Well Designer Well

Horizontal/TVD displacement greater than 2.5

Wells with more than 85º deviation

Wells with significant turn in the horizontal plane of 30 to 180 degrees, and turn not restricted by inclination

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Directional wells Radius Classification

Build Rate ( degrees/30 meter )

Radius (meter)

Long Radius

1- 6

1719 – 286

Medium Radius

7 – 30

285 – 57

Intermediate Radius

30 - 70

56 – 24

Short Radius

71 - 150

23 - 11.5

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Reasons for D.D

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Side-tracking existing well (because of hole problems or fish or reaching new targets) Restricted surface locations (inaccessible locations) To reach multiple targets To reduce number of offshore platforms Horizontal Drilling To reach thin reservoirs (using horizontal wells) Salt dome drilling (directing the well from the salt dome to avoid casing collapse problems) To avoid gas or water coning For intersecting fractures Relief wells For controlling vertical wells Shoreline drilling

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D.D applications

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D.D applications (multiple targets)

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D.D applications (relief well)

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D.D applications (side-tracking)

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D.D applications (inaccessible locations)

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D.D applications (shoreline drilling)

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D.D applications (salt dome drilling)

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D.D applications (fault drilling)

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D.D applications (horizontal well)

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Horizontal well z

z

Horizontal wells z

The Incl. reaches to 90° through reservoir section :‫ ﺑﻴﺸﺘﺮﻳﻦ ﻛﺎرﺑﺮد در اﻓﺰاﻳﺶ ﺑﻬﺮه ﺑﺮداري و در ﻣﺨﺎزن ﺧﺎص ﻣﺜﻞ‬z

z

Fracture Limestone & Low permeability zone

Horizontal drain holes: ‫ ﻓﻮﺗﻲ‬30 ‫ ﺧﺎص ﺑﺮاي اﻳﺠﺎد زاوﻳﻪ ﺧﻴﻠﻲ ﺳﺮﻳﻊ و در ﻳﻚ ﺷﻌﺎع‬BHA

z

2° per ft Deep Kickoff and Build :‫ﺷﺒﻴﻪ ﻧﻮع‬

z

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z

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Drilling Fluid Selection z

Virtually all of the considerations for choosing a fluid for drilling a vertical hole apply to choosing a fluid for a directional hole: z z z z z z z

Formation protection Hole cleaning Lubricity Inhibition Fluid weight required Economics Environmental impact

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Reference Systems and Coordinates z

Depth references z

Measured Depth (MD) Pipe tally, wire line depth counter, or mud loggers depth counter True Vertical Depth (TVD) calculated from the deviation survey data z

z

z

z

Inclination references z

is the angle (in degrees) between the vertical and the well bore axis at a particular point.

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TVD & MD

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Reference Systems and Coordinates

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Reference Systems and Coordinates z

Azimuth references z z z

z

Magnetic North (measured by MWD) True (Geographic) North Grid North

Horizontal departure or displacement •

Horizontal distance between rig location & the target.

Note:

True north = magnetic north ± (declination) Directional Drilling presentation

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Reference Systems and Coordinates

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Reference Systems and Coordinates

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Types of Directional well trajectories

1. 2. 3. 4. 5.

Build and hold Build-hole-drop (S type) Build-hold-drop-hold (modified S type) Continuous build Deep Kickoff and Build

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Types of Directional well trajectories

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Build and hold z

Features: z z z z z z

z

Shallow kick-off point (KOP) Build-up section Tangent section Penetrate target at an angle equal to the Max buildup angle No major changes in incl. & azimuth After build up section Incl: 15 – 55 deg or may be more

Applications: z z

Deep wells with large horizontal displacements Moderately deep wells with moderate horizontal displacement, where intermediate casing is not required

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Build-hole-drop (S type) & Build-hold-drop-hold (modified S type)

Modified S type

S type

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Build-hole-drop (S type) & Build-hold-drop-hold (modified S type)

z

z

Features: z z z z

Shallow KOP Build-up section Tangent section Drop-off section

Applications: z z z z

z

There are several variations: z z z

Build, hold &drop back to vertical (illustrated above) Build, hold, drop & hold (illustrated above) Build, hold & continuous drop through reservoir

z

z

Multiple pay zones Reduces final angle in reservoir Lease or target limitations Well spacing requirements Deep wells with small horizontal displacements

Disadvantages: z z z

Increased torque & drag Risk of key seating Logging problems due to inclination

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Continuous build z

Features: z z z

Decrease in torque & drag Lowest risk of key seating Continuous build rate

KOP

Build Section

z

Applications: z

This type occurs when using down-hole motors with bent sub.

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Target

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Deep Kickoff and Build z

Features: z z z

z

Applications: z z z

z

Deep KOP Build-up section Short tangent section (optional)

Salt dome drilling Sidetracking Appraisal wells to assess the extent of a newly discovered reservoir

Disadvantages: z

z

z z

Formations are harder so the initial deflection may be more difficult to achieve Harder to achieve desired tool face orientation with down hole motor deflection assemblies (more reactive torque) Longer trip time for any BHA changes required Build up rate is more difficult to control

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Calculation of a well trajectory (build-hold where X3 < r1) z

Radius of curvature: 180 r1 =

π

×

1 q

q= build rate (deg/100 ft) z

Maximum inclination angle, ɵ, when X3