IADC Drilling Manual


eBook Version (V.11)















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©

2000, International Association of Drilling Contractors
All Rights Reserved
In publishing this Manual, IADC makes no warranty or representation, expressed or
implied, with respect to the accuracy, completeness, usefulness, or fitness for purpose of
the information contained herein, or that the use of any information, method, process, or
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IADC Contact Information:

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Mailing Address
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Copyright
©
2000
All Rights Reserved by International Association of Drilling Contractors




The IADC Drilling Manual Published by
Technical Toolboxes, Inc.


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Houston, Texas 77098
Tel: 713-630-0505

Fax: 713-630-0560
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Acknowledgements


The 1991 Drilling Technology Committee of IADC, chaired by W.M. “Sonny” Rogers,
authorized the preparation of the eleventh edition of this manual. This edition is the
eBook version of the entire eleventh edition. This version is fully searchable and has new
color graphics and photographs.

Jay Norton, Chairman of the Drilling Manual Subcommittee and many of the Industry’s
most knowledgeable people have reviewed, rewritten, and added chapters for the benefit
of the user. Their time, effort, and dedication, in spite of difficult economic times for the
industry, is greatly appreciated.

The Association would again like to express its appreciation to the many contributors to
previous editions. Without their early interest, the manual would not have evolved to its
present status.

The following people served on the 1991-92 Rewrite Subcommittee and as Chairman for
the Chapter rewrite task groups:

John Altermann Reading and Bates
Robert Bennett Millpark Drilling Fluids
Bill Bingham MH Koomey
Sonny Cain SWACO

Jerry Cerkovnik Hughes Christiansen
Otis Danielson Consultant
John Gieck Baker Hughes
Bill Halliday Millpard Drilling Fluids
Bruce Harwell DI Industries
Larry Jones Consultant
Jay Norton Norton Drilling
Paul O’Connor O’Connor and Young Drilling
Chuck Rayburn Grasso Oil Services
Chris Reinsvold Hughes Christiansen
W.M. “Sonny” Rogers Tuboscope
Jim Senger Security Dresser
Jim Sikes Sonat Offshore
Jack Smith Baker Hughes
Tom Smith Tom Smith Consulting
Mickey Thomas Halliburton Services
Jim West PETEX
Wayne Wilson Tuboscope


Special Acknowledgement for the eBook version

Special thanks are due to Hal Kendall of Noble Drilling Corporation for providing many of
the enhanced graphics and illustrations used in this electronic version of the 11th Edition
of the "IADC Drilling Manual".









This Page Left Intentionally Blank

1
International Association of Drilling Contractors
Table of Contents
Table of Contents - IADC Drilling Manual
Chapter A - Bit Classification and Grading A-1
A-1 First Revision To The IADC Fixed Cutter Dull Grading System A-7
Contributors A-7
Summary A-7
Abstract A-7
Introduction A-7
System Enhancements A-7
Application Of Dull Grading System A-9
Conclusion A-14
References A-14
Acknowledgements A-14
A2 - IADC Fixed Cutter Classification System A-16
Development Of A New IADC Fixed Cutter Drill Bit Classification System A-16
Contributors A-16
Abstract A-16
Introduction A-16
Background A-17
Proposed System A-20
Conclusions A-28
References A-28
Acknowledgements A-28

A3 - The IADC Roller Bit Classification System A-29
Summary A-29
Series And Type A-33
Characters 1 And 2 A-33
Cutting Action A-33
Tooth Count And Geometry A-34
Insert Shape Comparison A-34
Cone Design And Orientation A-34
Cutting Structure Metallurgy A-35
Bearing/Gage Design Configuration (Character 3) A-35
Features Available (Optional 4th Character) A-37
A4 - IADC Roller Bit Dull Bit Grading System A-60
Description of the IADC Roller Bit Dull Bit Grading System A-60
A4. IADC Roller Bit Dull Grading System A-60
Discussion Of Dulling Characteristics A-66
BC (Broken Cone) or BF (Bond Failure) - (Fig. A4-3) A-67
BT (Broken Teeth) - (Fig. A4-4) A-68
BU (Balled Up) - (Fig. A4-5) A-69
CC (Crocked Cone) - (Fig. A4-6) A-70
CD (Cone Dragged) - (Fig. A4-7) A-71
CI (Cone Interference) - (Fig. A4- 8) A-72
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IADC Drilling Manual - Eleventh Edition
CR (Cored) - (Fig. A4-9) A-73
CT (Chipped Teeth) - (Fig. A4-10) A-74
ER (Erosion) - (Fig. A4-11) A-75
FC (Flat Crested Wear) - (Fig. A4-12) A-76
HC (Heat Checking) - (Fig. A4-13) A-77
JD (Junk Damage) - (Fig. A4-14) A-78

LC (Lost Cone) - (Fig. A4-15) A-79
LN (Lost Nozzle) - (Fig. A4-16) A-80
LT (Lost Teeth) - (Fig. A4-17) A-81
OC (Off Center Wear) - (Fig. A4-18) A-82
PB (Pinched Bit) - (Fig. A4-19) A-83
PN (Plugged Nozzle) - (Fig. A4-20) A-84
RG (Rounded Gage) - (Fig. A4-21) A-85
SD (Shirttail Damage) - (Fig. A4-22) A-86
SS (Self Sharpening Wear) - (Fig. A4-23) A-87
TR (Tracking) - (Fig. A4-24) A-87
WO (Washed Out Bit) - (Fig. A4-25) A-88
WT (Worn Teeth) (Fig. A4-26) A-89
NO (No Dull Characteristics) A-89
Chapter B - Drill String B-1
Preface B-5
B1. Drill String B-6
Introduction B-6
I. Weld-on Tool Joints B-6
B2. Steel Drill Pipe B-45
B3. Tool Joints Care And Handling B-54
I. Cleaning and Inspection B-54
II. Picking Up the Drill String B-55
III. Thread Compounds B-58
IV. Breaking In New Tool Joints B-58
V. Tripping B-59
VI. Laying Down Drill String B-67
VII. Damage and Failures Cause Prevention B-69
VIII. Repair of Tool Joints B-87
IX. Emergency Procedures B-93
X. Transportation B-94

XI. Storage B-95
XII. Floor Handling Procedures B-96
B4. Drill String Operating Limits B-104
I. Fatigue and Lateral Forces caused by Dog Legs and Floating Vessels B-104
II. Fatigue Caused by Other Factors B-115
III. Critical Rotary Speed B-120
IV. Collapsed Pipe From Drill Stem Test and BOP Test B-120
V. Transition from Drill String to Drill Collars B-121
VI. Maximum Allowable Pull and Rotary Torque B-121
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VII. Make up Torque versus Drilling Torque B-123
IX. Dynamic Loading of Drill Pipe during Tripping B-125
X. Biaxial Loading of Drill Pipe B-125
XI. Drill String Design B-126
XII. References B-126
B5. Drill String Corrosion B-127
I. Introduction B-127
Il. Corrosion B-127
III. Sulfide Stress Cracking B-132
IV. Drilling Fluids Containing Oil B-135
B6. Drill String Inspection And Classification B-136
I. Purpose B-136
II. Drill String Marking and Identification B-136
III. Drill Pipe And Tubing Work Strings B-136
IV. Tool Joints B-144
B7. Aluminum Drill String B-148
Introduction B-148
II. Installation and Removal of Tool Joints B-148

III. Aluminum Drill Pipe B-148
IV. Drill String Care and Handling B-150
V. Drill String Maintenance B-151
VI. Drill String Operating Limits B-151
B-8 Glossary Of Drill String Terms B-154
Chapter C - Casing and Tubing C-1
I. Care And Use Of Casing C-4
Introduction C-4
I. Transportation C-4
II. Preparation And Inspection Before Running C-4
III. Rig Equipment C-4
IV. Pre-running Preparations C-5
V. Running Casing C-6
VI. Causes Of Casing Troubles C-16
VII. Recovery Of Casing C-19
VIII. Reconditioning C-20
IX. Field Welding Of Attachments On Casing C-20
II. Care And Use Of Tubing C-24
Introduction C-24
I. Transportation C-24
II. Preparation And Inspection Before Running C-24
III. Rig Equipment C-24
IV. Pre-running Preparations C-25
V. Running C-26
VI. Pulling Tubing C-36
VII. Causes Of Tubing Troubles C-37
VIII Reconditioning C-37
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IADC Drilling Manual - Eleventh Edition

Chapter D - Drill Collars, Kellys, Subs and Heavy
Weight Drill Pipe D-1
Preface D-3
D1. Drill Collars: Specifications & Usage D-4
I. Specifications D-4
D2. Drill Collars: Care And Maintenance D-36
I. Recommended Drill Collar Care And Maintenance D-36
D3. Kellys: Specifications D-59
I. Specifications D-59
D4. Kellys: Care And Maintenance D-66
I. Care And Maintenance D-66
D5. Drill Stem Subs: Specifications D-71
I. Class And Type D-71
II. Dimensions For Type A & B Subs D-77
III. Dimensions For Type C (Swivel) Subs D-79
IV. Mechanical Properties Of Drill Stem Subs D-79
V. Kelly Saver Subs D-80
D6. Kelly Valves: Specifications D-81
I. Upper Kelly Cocks D-81
II. Lower Kelly Cocks D-85
III. Automatic Mud Saver Valves D-87
IV. Kelly Saver Subs D-87
D-7 Specifications Of Heavy Weight Drill Pipe D-88
Care and Maintenance of HWDP D-89
D8 - Glossary of Drill String Terms D-90
Chapter E - Pipe Handling Equiptment E-1
E1. Pipe Handling Equipment E-4
Introduction E-4
I. Specifications E-4
E2. Bushings And Slips E-9

I. Specifications E-9
II. Care And Maintenance E-13
E3. Elevators E-23
I. Drill Pipe Elevators E-23
II. Drill Collar Elevators E-25
E4 - Drill Collar Slips and Safety Clamps E-30
I. Drill Collar Slips E-30
II. Drill Collar Safety Clamps E-30
E5. Elevator Links, Block, Hook And Swivel Specifications E-31
Chapter F - Drawworks Brakes F-1
Introduction F-3
I. Maintenance Procedures F-4
II. Brake Linings (Blocks) F-5
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III. Brake Bands F-5
IV. Brake Rims (Flanges) F-6
V. Brake Linkage F-20
VI. Company Policy F-20
Chapter G - Chains and Sprockets G-1
G1. Construction and Specifications G-4
I. Roller Chain Construction And Types G-4
II. Sprockets. G-16
G2. Installation, Lubrication And Maintenance G-22
I. Installation G-22
II. Lubrication G-25
III Maintenance G-36
Roller Chain Drive Troubleshooting Guide G-41
Chapter H - Rotary Hose and Swivels H-1

H1. Rotary Hose Specifications H-4
I. Introduction H-4
II. Specifications H-4
H2. Rotary Hose Care And Maintenance H-9
I. Recommended Dimensions H-9
II. Care And Maintenance H-10
H3. Swivels Specifications H-12
I. Swivel Pressure Testing H-12
II. Swivel Gooseneck Connection H-12
III. Swivel Subs H-13
H4. Inspection H-14
I. Inspection H-14
Chapter I - Engines I-1
I. Engines - Care And Maintenance I-4
I. Installation I-4
II. Maintenance I-9
III. Operating Troubles And Their Causes - Diesel Engines I-14
IV. Intake Vacuum vs Load I-18
Chapter J - Pumps J-1
J-1 Introduction - Pumps J-4
J-2 Surface and Mud System J-13
I. Suction Mud System J-13
II. Discharge System J-17
III. Drilling Fluids And Their Effect On Expendable Pump Parts J-18
J-3 Pump Parts, Theory and Function J-23
I. Pistons J-23
II. Duplex Piston Rods J-25
III. Rod Lubricants J-27
IV. Liner Packing J-28
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International Association of Drilling Contractors
IADC Drilling Manual - Eleventh Edition
J-4 Removal and Installation of Fluid Ends J-32
I. General - Removal and Installation of Fluid Ends J-32
II. Duplex Pump Disassembly J-32
III. Duplex Pump-assembly J-37
IV. Duplex Pump Piston Assembly J-46
V. Single Acting Pump Disassembly J-54
VI. Single Acting Pump Assembly J-56
VII. Single Acting Piston Assembly J-57
IX. Valve and Seat J-64
J-5 Pump Problems, Failures and Analysis J-74
I. Priming and Starting Instructions J-74
II. Pistons and Liners J-74
III. Fluid End Piston Rod and Packing J-77
IV. Valves and Seats J-78
V. Reducing Pump Volume J-79
VI. Centrifugal Pump Care and Maintenance J-80
VII. Checklists J-82
J6. Power End Maintenance J-84
I. Pump Storage J-90
J7. Preventive Maintenance J-91
I. Planned Preventative Maintenance J-91
II. Establishing a Preventative Maintenance Program J-92
III. Advantages of programming: J-94
Chapter K - Well Control Equipment and Procedures
K-1
Disclaimer and Credits K-3
K-1 Blowout Preventer Stack Equipment K-5
I. Annular Type Blowout Preventer K-5

II. Ram Type Blowout Preventer K-6
III. Typical Bop Stack Arrangement And Testing Procedures For A Surface Stack K-11
IV. Inside Blowout Preventers K-36
V. Choke Manifold K-43
VI. Diverter Systems K-46
K2. Blowout Preventer Control Systems K-54
A. Surface Bop Stacks, (Land Rigs, Offshore Jackups, And Platforms) K-54
B. Subsea Bop Stacks K-61
C. Remote Operated Choke Controls K-71
D. Diverter Control Systems K-73
E. Control Systems Typical Capacity And Performance Data / Calculations K-77
K3. Well Control Procedures K-92
Basic Principles K-92
II. Pre-kill Procedures K-93
III. Formation Pressure Integrity Information K-96
IV. Kill Techniques K-99
K-4 Glossary of Well Control Terms K-108
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Table of Contents
Chapter L - Derricks and Masts L-1
L-1 Ratings of L Derricks and Masts L-4
Ratings L-4
L-2 Inspection Report of Derricks and Masts L-20
Derricks And Masts L-20
A. Derricks And Masts L-21
B. Substructure And Vertical Extension L-25
C. Deadline Anchor And Supports L-26
Chapter M - Wire Rope M-1
M1. Wire Rope: Specifications M-4

I. Introduction M-4
II. Definition M-4
III. Wire Rope Nomenclature M-4
IV. Wire - Rope Sizes And Constructions M-6
M2. Care And Handling Of Wire Rope M-15
I. Field Care And Use Of Wire Rope M-15
II. Socketing Of Wire Rope M-24
III Attachment Of Wire Rope Claps To Wire Rope M-27
IV. Casing-line And Drilling Line Reeving Practice M-32
M3. Factors Affecting Service Life Of Wire Rope M-38
M4. Ton Mile Calculations M-40
A. Introduction M-40
B. Examples Of Ton-mile Calculations M-44
C. Ton-miles Per Foot Cut M-48
D. Ton Mile Calculations - Drilling Ton Miles for Top Drive (Drilling with
Stands) M-49
M5. Cut-off Program M-50
C. Union Wire Rope Cut-Off Program For Rotary Drilling Line M-51
M-6 Drum And Reel Capacity M-84
A. Design Factor M-84
B. Design Factor Charts M-90
M-7 Wire Rope - Ton Mile Calculations - Special Applications M-105
M-8 Appendix - Ton Mile Formulas M-109
1. Round-Trip Operations: M-109
2. Drilling Operations: M-109
3. Coring Operations: M-110
4. Setting Casing Operations: M-111
5. Short Trip Operations: M-111
Chapter N - Lubrication N-1
N1. Lubrication N-4

I. Conditions N-4
IIA. Glossary N-4
IIB: Definitions General N-5
IIC. Definitions Lubricant Additives N-7
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International Association of Drilling Contractors
IADC Drilling Manual - Eleventh Edition
N2. Types Of Lubrication N-9
I. Engine Crankcase Oil N-9
C. Government and Industry Specifications N-10
II. Industrial Gear Oils N-11
III. Hydraulic Oils N-12
IV. Grease N-13
V. Tool Joint Lubricants N-14
VI. Rust Preventives N-14
N3. Lubrication Practices N-15
I. Introduction N-15
II. General Hints On Lubrication N-15
III. Cooling System N-15
IV. Record Keeping N-16
V. Storage And Handling Of Lubricants N-18
N4. Cold Weather Conditions N-19
1. Introduction N-19
II. Rig Enclosures N-19
III. Engines And Power Plants N-19
IV. Chain Drives, Compounds, Gear Reducers, Slush Pumps & Rotary Tables N-20
V. Grease Applications N-21
VI. Thread Lubricants N-22
VII. Blow-out Preventers N-22
VIII. Machinery Storage N-22

IX. Lubricant Storage N-22
X. Summary N-23
XI. Fuel N-23
Chapter O - Drilling Fluids O-1
1. Drilling Fluids: Functions And Tests O-4
I. General O-4
II. Functions O-4
III. Test and Mud Properties O-4
IV. Factors Affecting Mud Performance and Cost O-6
2. Types Of Drilling Fluids O-7
I. Water Based Drilling Fluids O-7
II. Oil Muds O-13
3. Trouble Shooting O-14
I. Problems O-14
II. Specific Problems O-16
4. Calculations O-23
I. Calculations O-23
II. Additional Aids O-24
5. Additives For Drilling Fluids O-33
I. Definitions for Drilling Fluid Classification O-33
II. Drilling Fluid Systems O-33
III. Fluid Additive Functions O-34
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International Association of Drilling Contractors
IADC Drilling Manual - Eleventh Edition
D. Drilling Fluid Property Equations R-133
R-13-8 Nomenclature for Equations - Smith Int. R-134
R-13-9 Nomenclature and Terminology R-137
R-13-10. Pipe Flow Equations R-138
R-13-11. Annular Flow Equations R-138

R-13-12. Bit Hydraulic Calculations R-139
R-13-13. Chip Rate Calculations R-140
R-13-14. Completed Work Sheet R-141
R-13-15. Blank Work Sheet R-142
Chapter T - Cementing T-1
T1. Cementing T-4
I. Introduction T-4
II. Types Of Cement Used In Oil Wells T-4
T2. Casing Strings T-9
I. Introduction T-9
II. Plug Back Cementing T-12
III. Squeeze Cementing T-15
IV. Horizontal Well Completions T-21
T3. Balancing A Plug T-22
I. Balancing A Plug T-22
II. Calculating Fillup T-24
III. Pumping Large Diameter Surface-string Up The Hole T-24
T-4. Estimating Cement Required For Various Cementing Jobs T-26
Glossary of Cementing/Casing Terms T-27
Chapter U - Electric Drilling Rigs U-1
U-1. Silicon Controlled Rectifier Systems U-4
1. Introduction U-4
A. DC/DC and SCR Systems U-4
B. DC Drilling Motors U-4
U-2. SCR (AC/DC) Power Systems U-6
A. AC Electrical Power Generation U-6
A3. AC Switchgear U-7
B. AC/DC Conversion U-8
U-3. DC/DC Power Systems U-13
A. Introduction U-13

B. Controls U-13
C. Braking U-13
D. System Protection U-14
E. Driller's Console U-14
U-4. Maintenance U-15
General U-15
Maintenance Section Outline U-15
Daily Maintenance: U-22
Monthly Maintenance: U-22
Repair: U-22
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Table of Contents
U-5. Technical Index U-23
1. Maintenance Checklists: U-23
2. Reference Handbooks U-24
Chapter V - General Information V-1
Introduction V-3
1. Selected API Publications (Producton) V-4
Introduction V-4
Belting V-4
Derricks And Masts V-4
Tubular Goods V-4
Valves And Wellhead Equipments V-6
Drilling Equipment V-6
Hoisting Tools V-7
Wire Rope V-7
Oil Well Cements V-7
Drilling Fluid Materials V-8
Drilling Well Control Systems V-9

Drilling And Production Recommended Practices V-9
Special Publications V-10
2. Hole and Pipe Data V-13
Capacity V-13
Displacement of Hole and Pipe V-22
Volume and Height between Pipe and Casing: V-27
Volume and Height between Pipe and Hole: V-39
3. Field Gas Lines V-49
Pipeline Flow Of Gas Formulae And Conversions V-49
Gas Delivery, Based on 1000 Ft pipeline lengths V-51
Gas Delivery, Based on 1 Mile pipeline lengths V-54
Gas Delivery, Based on 10 Mile pipeline lengths V-57
4. Waterlines - Line Pipe Capacities V-60
5. Tank and Pit Capacity V-62
6. Conversion Factors V-68
7. Density of Oilfield Materials and Wood V-80
8. Density of Fluids and Petroleum Products V-82
9. Soil Bearing Capacity V-83
Chapter Y - Drilling Mud Processing Y-1
1. Introduction - Solids Control Removal Systems Y-4
A. Overview Y-4
B. Solids Removal Theory Y-5
C. Equipment Arrangement Y-9
II. Solids Control Equipment Y-11
A. Shale Shakers Y-11
B. Degassers Y-26
C. Hydrocyclones Y-30
D. Mud Cleaners Y-39
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International Association of Drilling Contractors

IADC Drilling Manual - Eleventh Edition
E. Centrifuges Y-50
III. Surface Circulating Equipment Y-55
A. Introduction Y-55
B. Considerations and Methods for Sizing Surface Mud Systems Y-55
C. Special Considerations Y-56
D. Sizing Steel Pits Y-57
E. Earthen Pits Y-58
F. Reserve and/or Waste Pits Y-59
4. System Rig-up Information Y-61
A. Solids Control System Layout Considerations Y-61
B. Centrifugal Pump Selection and Piping Design Y-70
C. Mud Troughs After the Shale Shakers Y-88
Chapter Z - Glossary Z-1
IADC Glossary - A Z-3
IADC Glossary - B Z-4
IADC Glossary - C Z-7
IADC Glossary - D Z-10
IADC Glossary - E Z-13
IADC Glossary - F Z-13
IADC Glossary - G Z-15
IADC Glossary - H Z-17
IADC Glossary - I Z-18
IADC Glossary - J Z-19
IADC Glossary - K Z-20
IADC Glossary - L Z-20
IADC Glossary - M Z-21
IADC Glossary - N Z-23
IADC Glossary - O Z-23
IADC Glossary - P Z-24

IADC Glossary - Q Z-26
IADC Glossary - R Z-26
IADC Glossary - S Z-30
IADC Glossary - T Z-34
IADC Glossary - U Z-36
IADC Glossary - V Z-36
IADC Glossary - W Z-36
IADC Glossary - X Z-38
IADC Glossary - Y Z-38
IADC Glossary - Z Z-38
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A-2
International Association of Drilling Contractors
IADC Drilling Manual - Eleventh Edition
Table of Contents - Chapter A
Bit Classification and Grading
A-1 First Revision To The IADC Fixed Cutter Dull Grading System A-7
Contributors A-7
Summary A-7
Abstract A-7

Introduction A-7
System Enhancements A-7
Application Of Dull Grading System A-9
Conclusion A-14
References A-14
Acknowledgements A-14
A2 - IADC Fixed Cutter Classification System A-16
Development Of A New IADC Fixed Cutter Drill Bit Classification System A-16
Contributors A-16
Abstract A-16
Introduction A-16
Background A-17
Proposed System A-20
Conclusions A-28
References A-28
Acknowledgements A-28
A3 - The IADC Roller Bit Classification System A-29
Summary A-29
Series And Type A-33
Characters 1 And 2 A-33
Cutting Action A-33
Tooth Count And Geometry A-34
Insert Shape Comparison A-34
Cone Design And Orientation A-34
Cutting Structure Metallurgy A-35
Bearing/Gage Design Configuration (Character 3) A-35
Features Available (Optional 4th Character) A-37
A4 - IADC Roller Bit Dull Bit Grading System A-60
Description of the IADC Roller Bit Dull Bit Grading System A-60
A4. IADC Roller Bit Dull Grading System A-60

Discussion Of Dulling Characteristics A-66
BC (Broken Cone) or BF (Bond Failure) - (Fig. A4-3) A-67
BT (Broken Teeth) - (Fig. A4-4) A-68
BU (Balled Up) - (Fig. A4-5) A-69
CC (Crocked Cone) - (Fig. A4-6) A-70
A-3
International Association of Drilling Contractors
Chapter A: Bit Classification and Grading
CD (Cone Dragged) - (Fig. A4-7) A-71
CI (Cone Interference) - (Fig. A4- 8) A-72
CR (Cored) - (Fig. A4-9) A-73
CT (Chipped Teeth) - (Fig. A4-10) A-74
ER (Erosion) - (Fig. A4-11) A-75
FC (Flat Crested Wear) - (Fig. A4-12) A-76
HC (Heat Checking) - (Fig. A4-13) A-77
JD (Junk Damage) - (Fig. A4-14) A-78
LC (Lost Cone) - (Fig. A4-15) A-79
LN (Lost Nozzle) - (Fig. A4-16) A-80
LT (Lost Teeth) - (Fig. A4-17) A-81
OC (Off Center Wear) - (Fig. A4-18) A-82
PB (Pinched Bit) - (Fig. A4-19) A-83
PN (Plugged Nozzle) - (Fig. A4-20) A-84
RG (Rounded Gage) - (Fig. A4-21) A-85
SD (Shirttail Damage) - (Fig. A4-22) A-86
SS (Self Sharpening Wear) - (Fig. A4-23) A-87
TR (Tracking) - (Fig. A4-24) A-87
WO (Washed Out Bit) - (Fig. A4-25) A-88
WT (Worn Teeth) (Fig. A4-26) A-89
NO (No Dull Characteristics) A-89
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Chapter A: Bit Classification and Grading
Chapter A
Bit Classification And Grading
The IADC Drilling Manual is a series of reference guides for use in field operations covering a variety of subjects
related to drilling operations.
The contents of this (these) volume (s) are assembled by a wide range of members of the drilling industry inter-
ested in providing information to field personnel to encourage proper operations, maintenance and repair of equip-
ment and training and safety of personnel.
It is not intended that the contents of this manual replace or take precedence over manufacturer's, operators or
individual drilling company recommendations, policies and/or procedures. In those areas where local, state and
federal law is in conflict with the contents then it is deemed appropriate to adhere to suer laws. IADC has endeav-
ored to insure the accuracy and reliability of this data, however, we make no warranties or guarantees in connec-
tion with these recommendations.
As technology continues to develop this manual will be updated. It is important that the user continue to update
their knowledge through research and study.
The following industry representatives have contributed to the development and updating of this chapter:
FIXED CUTTER BITS
B. D. Brandon Hughes Christensen

Jerry Cerkovnik Hughes Christensen
Earl Koskie DBS
B. B. Bayoud Hughes Christensen
Fred Coston Smith Diamond
R. I. Clayton Security Division Dresser Industries
M. E. Anderson Hughes Christensen
K. T. Hollister Hycalog
Jim Senger Security Division Dresser Industries
Ralph Neimi Cliffs Drilling
ROLLER CONE BITS
Ed Andrews Kenting Apollo Drilling, Inc.
Dennis Cox Enserch
Jim Dahlems Security Division Dresser Industries
Eric Elrod Walker-McDonald Mfg. Co.
Roy Estes Rock Bit International Inc.
Martyn Fear BP Exploration
John Gieck Hughes Tool Company
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IADC Drilling Manual - Eleventh Edition
Sam Hampton Helmerich & Payne
Hal Kendall Amoco
William Kost Smith International
Dave Lafuze Varel Manufacturing Company
Rick Lyon Sandvik Rock Tools
Dave McGehee Reed Tool Company
Ralph Neimi Cliffs Drilling
Chris Reinsvold Hughes Tool Company
Jim Senger Security Division Dresser Industries
Steve Steinke Smith International

Brian Tarr Mobil Exploration
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IADC Drilling Manual - Eleventh Edition
Figure A1-1 Format of the Dull Bit Grading Chart
Eight factors are recorded: the first four spaces describe the extent and location of wear of the "Cutting Struc-
ture". The next two spaces address other criteria for bit evaluation, with the fifth space reserved for grading
"Bearing" wear of roller cone bits. This space is always marked with an "X" when fixed cutter bits are graded.
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Figure A1-3 Inner/Outer Row Designa-
tion
Average wear is calculated by simply averaging the individual grades for each cutter in the area.
Dull Characteristics: Space 3. See A1-1d.
Figure A1-1d Code for Dulling Characteristics
The most prominent or "primary" physical change from new condition of a cutter is recorded in the third space.
"Other" dull characteristics of the bit are noted in the seventh space the difference being that space 3 describes
cutter wear, while space 7 may concern other wear characteristics of the bit as a whole. Codes for dull character-
istics of both categories are listed in the table in Figure 1, including the addition of "BF" for bond failure.
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Chapter A: Bit Classification and Grading
Location: Space 4. See A1-1c.
Figure A1-1b Code for Location on Bit
LOCATION
C - Cone
N - Nose (Row)
T - Taper
S - Shoulder

G - Gauge
A - All Areas Rows
M - Middle Row
H - Heel Row
The fourth space is used to indicate the location of the primary dull characteristic noted in the third space.
Locations are designated in the diagrams of Figure A1-4.
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Chapter A: Bit Classification and Grading
Figure A1-1c Code for Bit Bearing, Seals
This space is used only for roller cone bits. It will always be marked "X" for fixed cutter bits.
Gauge: Space 6. See Figure A1-1e.
Figure A1-1e Code for Gauge
The sixth space is used to record the condition of the bit gauge. 'I' is used if the bit is still in gauge. Otherwise, the
amount the bit is undergauge is recorded to the nearest 1/16th of an inch.
Additional "Remarks"
Other Dull Characteristics: Space 7. See Figure A1-1d.
In the seventh space, secondary evidence of bit wear is noted. Such evidence may relate specifically to cutting
structure wear, as recorded in the third space, or may note identifiable wear of the bit as a whole, such as "ero-
sion". Many times, this "secondary" dull grade identifies the cause of the dull characteristic noted in the third space.
Codes for grading both "primary" and "secondary" dull characteristics are listed in the table shown in Figure A1-1d.
The designations "RR" and "NR" have been included as options for noting whether the bit is rerunnable or not.
Examples of dull characteristics are shown in Figure A1-2
Reason Pulled: Space 8. See Figure A1-1f.