Bits

Drilling Bits CASING

Objectives At the end of this training session, you will be able to:
List the different type of bits
Describe the different rock failure mechanism
Describe the IADC (International Association of Drilling Contractors) bit coding and dull bit grading
Describe the effect of change in weight on bit, rpm, hole size, mud weight and solids content on bit performance

Introduction Drilling bits selection is crucial to the performance of all drilling projects. Understanding the different types of bits and their respective applications is a pre-requisite to bit selection. Not only the right bit in the right application but also running it with the right operating parameters. Well engineers must stay abreast of the latest developments to ensure optimum bit selection.

Bit Types

Bit Types Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Roller Cone

Diamond

TSP

Impregnated

Diamond

Mill Tooth

Roller Bearing

Insert

Journal Bearing

PDC (Polycrystalline Diamond Compact)
Use artificially made diamonds

Drill Bits


Run successfully with downhole motors

Fixed Cutter

PDC

Natural Diamond Courtesy of

Diamond

TSP

Impregnated

Diamond

Roller Cone

Mill Tooth

Roller Bearing

Insert

Journal Bearing

PDC bit: Elements 5 1

2

1. synthetic diamond cutters 2

3

2. support structures for the cutters 3. gauge protection inserts 4. Depth of cut limiters 5. nozzles.

Steel / Tungsten Carbide Courtesy of

PDC bit: Body Material
Steel body in one piece ⇒ High precision ⇒ simple repair ⇒ no weld


Tungsten Carbide matrix on steel shell ⇒ Erosion resistant

PDC bit: Cutting Elements 19 mm

BLADE PDC CUTTER

γ Courtesy of

16 mm

13 mm

11 mm

8 mm

Natural Diamond Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Diamond

TSP

Impregnated

Diamond

Roller Cone

Mill Tooth

Roller Bearing

Insert

Journal Bearing

Diamond Bit Profiles Taper or Double cone

Soft formation=>

Parabolic

=>

=>

=>

Shallow cone

=> Hard formation (More diamond coverage) Low ROP

Diamond bit : Design
Size and spacing of diamonds determines its use




Widely spaced diamonds : large pieces of soft sand and shale Medium spacing of large diamonds: wide range of sand, shale , limestone Smaller diamonds set in close pattern: hard formations

Natural Diamond bit: Elements



Natural Diamonds = hardest mineral But brittle and Temp dependant






Fluid circulation important

No cone , operates like a single unit Sensitive to shock and variation

Courtesy of

TSP (Thermally Stable Polycrystalline) Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Diamond

TSP

Impregnated

Diamond

Roller Cone

Mill Tooth

Roller Bearing

Insert

Journal Bearing

Cutting Elements - TSP
TSP

Courtesy of

Impregnated Diamond Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Diamond

TSP

Impregnated

Diamond

Roller Cone

Mill Tooth

Roller Bearing

Insert

Journal Bearing

Impregnated Diamond: Blades Bit Blade Matrix

Diamond Grit Courtesy of


Formation: medium hard to very hard, ABRASIVE!
Impregnated cutting element.
Distributed in a tungsten carbide matrix.
During heating (furnace) the Segments are bonded to the bit body.

Cutting Elements - Impregnated
Impregnated Diamond Blades

Courtesy of

ROLLER CONE Drill Bits

Alternative Names Fixed Cutter

Rock Bit Tri-Cone™

PDC

Natural Diamond Courtesy of

Roller Cone

Diamond

TSP

Impregnated

Diamond

Mill Tooth

Roller Bearing

Insert

Journal Bearing

Basic Types Of Roller Cone Bits

Tooth Bits
Mill Tooth Bits

Insert Bits
Tungsten Carbide Bits
Button Bits

Roller Cone Components Nose Cone #3 Gauge Row

Cone #1 Inner Row

Heel Row

Cone #2

Shirttail

Lug

Nozzle Pin

Bit Body

Roller cone bits: Nozzles SHROUDED TYPE

STANDARD TYPE

Mill Tooth Bits Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Roller Cone

Diamond

TSP

Impregnated

Diamond

Mill Tooth

Insert

Roller Bearing

Journal Bearing

Cutting Elements – Mill Tooth
Teeth and Hardfacing

Courtesy of

Insert Bits Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Roller Cone

Diamond

TSP

Impregnated

Diamond

Mill Tooth

Insert

Roller Bearing

Journal Bearing

Cutting Elements - Insert
Tungsten Carbide Inserts

Courtesy of

Tricone Bit - Roller Bearing Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Roller Cone

Diamond

TSP

Impregnated

Diamond

Mill Tooth

Insert

Roller Bearing

Journal Bearing

Roller Cone Bearing Systems Main Bearings

Roller Bearing Bit

Retention Bearings

Seals

Journal Bearing Bit

Tricone Bit - Roller Bearing

Main Bearing Retention Bearing Thrust Bearing Pin Bearing

Courtesy of

Tricone Bit - Journal Bearing Drill Bits

Fixed Cutter

PDC

Natural Diamond Courtesy of

Roller Cone

Diamond

TSP

Impregnated

Diamond

Mill Tooth

Insert

Roller Bearing

Journal Bearing

Tricone Bit - Journal Bearing

Main Bearing Retention Bearing Thrust Bearing Pin Bearing

Rock Failure Mechanisms

Failure Mechanisms Failure Mechanisms


Shear Failure

PDC BIT CONTINUOUS SHEARING


Compressive Failure

ROLLER CONE BIT CYCLIC COMPRESSION

Courtesy of

Drilling Mechanisms
Shear/Compressive Failure

NATURAL DIAMOND OR IMPREG BIT CONTINUOUS CRUSHING & ABRASION

Courtesy of

Drilling Mechanisms vs Bit Type

Scraping

Mill Tooth

Chipping and Crushing Insert Shearing

PDC

Ploughing / Grinding

Natural/Impregnated Diamond

Courtesy of

IADC Bit Classification

IADC Classification – Roller Cone 517G Cutting Structure Series

8-1/2” EHP 51

Soft Formations w ith Low Compressive Strength and High Drillability STEEL Medium to Medium TOOTH Hard Formations w ith BITS High Compressive Strength Hard Semi-Abrasive and Abrasive Formations Soft Formations w ith Low Compressive Strength and High Drillability Soft to Medium Formations w ith Low Compressive Strength INSERT Medium Hard BITS Formations w ith High Compressive Strength Hard Semi-Abrasive and Abrasive Formations Extremely Hard and Abrasive Formations

1 2 3

Cutting Structure Type (1 to 4) 1 refers to the softest formation in a particular Series and 4 refers to the hardest formation within the Series

4 5 6 7 8

Ref: SPE 23937 The IADC Roller Bit Classification System

Bearing/Gauge Description Standard Roller Bearing Roller Bearing Air Cooled Roller Bearing Gauge Protected Sealed Roller Bearing Sealed Roller Brg Gauge Protected Sealed Friction Bearing Sealed Frction Brg Gauge Protected

1 2 3 4 5 6 7

Features Available (Optional) A - Air Application B - Special Bearing Seal C - Center Jet D - Deviation Control E - Extended Nozzles G - Gauge/Body Protection H - Horizontal Steering Appl. J - Jet Deflection L - Lug Pads M - Motor Application S - Standard Steel Tooth T - Two Cone Bit W - Enhanced Cutting Structure X - Predominantly Chisel Tooth Insert Y - Conical Tooth Insert Z - Other Shape Insert

IADC Classification – Fixed Cutter M432 Body Material Steel or Matrix. Cutter Density PDC: 1 to 4, diamond bits: 6 to 8 (the lower the number, the lighter set the bit). 12-1/4” DS66H

Cutter Size/Type For PDC cutter, 1 indicates >24 mm, 2 is between 14 and 24 mm, 3 is between 8 and 14 mm and 4 is smaller than 8. For diamond bits, 1 represents natural diamond, 2 is for TSP, 3 is a combination of natural diamond and TSP and 4 is for impregnated. Profile The final digit indicates the general body style and varies from 1 (flat profile) to 4 (long flanked turbine style).

Fixed cutter IADC codes are intended only to provide a means for characterizing the general physical appearance of fixed cutter drill bits. Unlike the IADC classification for roller bits, these codes do not represent an application guideline. Ref: SPE 23940 Development of a New IADC Fixed Cutter Drill Bit Classification System

IADC Codes Tooth 1-1

Soft 1

2

1-3

3

2-1 Hard

IADC Codes Tooth Soft 1

2 3

Insert

4-1

4 5 6 7

Hard

8

8-3

IADC Codes Tooth

PDC

Soft 1 Insert 2

4

3

5 6 7

Hard

8

IADC Codes Tooth

PDC

Soft 1 Insert 2

4

3

5 6 7

Hard

8

Diamond

IADC Codes Tooth

PDC

Soft 1 Insert 2 3

4 5 6 7

Hard

8

Impregnated Diamond Diamond

IADC Bit Dull Grading Code

IADC Bit Dull Grading Code The International Association of Drilling Contractors has developed a standard methodology for describing used bits. This information is essential for detailed bit performance analysis. The methodology is composed of an 8 character code that describes bit wear and the reason why the bit was pulled. Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

LOCATION

B

G

BRNG/ SEALS

GAUGE 1/16”

Remarks OTHER CHAR

REASON PULLED

IADC Bit Dull Grading Code Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

LOCATION

B

G

Remarks

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED

The cutting structure is graded from 0 to 8 depending on the proportion of cutting structure lost (0 = Intact, 8 = 100% worn). Fixed Cutter Bits

Roller Cone Bits 0

1

2

3

4

Inner Cutting Structure (All Inner Rows)

Outer Cutting Structure (Gauge Row Only)

Cone 3 Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

5

6

7

8

Cone 1

Cone 2

IADC Bit Dull Grading Code Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics

LOCATION

B

G

BRNG/ SEALS

GAUGE 1/16”

Remarks OTHER CHAR

REASON PULLED

Roller Cone Bits *BC - Broken Cone BF - Bond Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Note that this is for the Primary dull characteristics.

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Fixed Cutter – Main Wear Characteristics POST OR STUD CUTTERS NO WEAR (NO)

CYLINDER CUTTERS

Courtesy of

NO WEAR (NO)

WORN CUTTER (WT)

WORN CUTTER (WT)

BROKEN CUTTER (BT)

BROKEN CUTTER (BT)

LOST CUTTER (LT)

BOND FAILURE (BF)

LOST CUTTER (LT)

EROSION (ER)

BOND FAILURE (BF)

Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics

BU - Balled Up

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Ref : IADC Drilling Manual – Eleventh Edition

BU – Balled Up Bit (primary) CD – Cone Dragged (secondary)

Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics

CT – Chipped Cutter

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics

LT – Lost Cutter

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Ref : IADC Drilling Manual – Eleventh Edition

BT – Broken Teeth/Cutters

Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics

RO – Ring Out

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Ref : IADC Drilling Manual – Eleventh Edition

JD – Junk Damage

Dull Characteristics – Some Examples Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics

WT – Worn Cutters

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Ref : IADC Drilling Manual – Eleventh Edition

SD - Shirttail Damage

Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

TR - Tracking

Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Ref : IADC Drilling Manual – Eleventh Edition

SS – Self Sharpening Wear

Dull Characteristics – Some Examples Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Ref : IADC Drilling Manual – Eleventh Edition

ER – Erosion

IADC Bit Dull Grading Code Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

LOCATION

B

G

BRNG/ SEALS

GAUGE 1/16”

Fixed Cutter Bits

Remarks OTHER CHAR

REASON PULLED

Roller Cone Bits N - Nose Row M - Middle Row G - Gauge Row A - All Rows

C - Cone N - Nose T - Taper S - Shoulder G - Gauge Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Cone 1, 2 or 3

IADC Bit Dull Grading Code Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

Fixed Cutter Bits This box is for roller cone bits. Fixed cutter bits will always be designated by "X".

LOCATION

B

G

BRNG/ SEALS

GAUGE 1/16”

Remarks OTHER CHAR

REASON PULLED

Roller Cone Bits Non Sealed Bearings A linear scale estimating bearing life used. (0 -No life used, 8 - All life used, i.e., no bearing life remaining.) Sealed Bearings E - Seals Effective F - Seals Failed N - Not Able to Grade

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

IADC Bit Dull Grading Code Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

LOCATION

B

G

BRNG/ SEALS

GAUGE 1/16”

Remarks OTHER CHAR

REASON PULLED

For all Bits The letter “I” is used to designate bits that are in gauge. If the bit is under gauge, the amount is recorded to the nearest 1/16” of an inch. For example, if the bit is 1/8” under gauge, this is reported as 2/16 or often only as 2.

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

IADC Bit Dull Grading Code Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

LOCATION

B

G

BRNG/ SEALS

GAUGE 1/16”

Remarks OTHER CHAR

REASON PULLED

This is for the Secondary dull char. and it uses the same codes as for the Primary dull char.

Fixed Cutter Bits BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion HC - Heat Checking JD - Junk Damage LN - Lost Nozzle LT - Lost Cutter NR - Not Rerunable PN - Plugged Nozzle RG - Rounded Gauge RO - Ring Out RR - Rerunable SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Cutters NO - No Dull Characteristics

Roller Cone Bits *BC - Broken Cone BF - Bone Failure BT - Broken Teeth/Cutters BU - Balled Up Bit *CC - Cracked Cone *CD - Cone Dragged CI - Cone Interference CR - Cored CT - Chipped Teeth/Cutters ER - Erosion FC - Flat Crested Wear HC - Heat Checking JD - Junk Damage *LC - Lost Cone

LN - Lost Nozzle LT - Lost Teeth/Cutters OC - Off-Center Wear PB - Pinched Bit PN - Plugged Nozzle/Flow Passage RG - Rounded Gauge RO - Ring Out SD - Shirttail Damage SS - Self Sharpening Wear TR - Tracking WO - Washed Out Bit WT - Worn Teeth/Cutters NO - No Dull Characteristic * Show Cone under Location 4

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

IADC Bit Dull Grading Code Cutting Structure INNER ROWS

OUTER ROWS

DULL CHAR

LOCATION

B

G

BRNG/ SEALS

GAUGE 1/16”

Remarks OTHER CHAR

REASON PULLED

For All Bits BHA - Change Bottom Hole Assembly DMF - Down hole Motor Failure DSF - Drill String Failure DST - Drill Stem Test DTF - Down hole Tool Failure RIG - Rig Repair CM - Condition Mud CP - Core Point DP - Drill Plug FM - Formation Change

HP - Hole Problems HR - Hours PP - Pump Pressure PR - Penetration Rate TD - Total Depth/Casing Point TQ - Torque TW - Twist Off WC - Weather Conditions WO - Washout -DrillString

Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information

Key to Dull Bit Grading: Grade a Lot of Dulls !

Photo courtesy of

BIT RECORD To be filled up at wellsite

BIT RECORD

Well : Date : Bit Data

Run Data

BHA Bit Size Bit type Serial IADC Nozzles Depth Depth Drilling ROP Bit krevs WOB No. No. (inch) & maker Number Code (1/32") IN (m)OUT (m) Time (m/hr)(drilling) (Klbs) 3 x 18, 1 1 1 16 T11C L15264 115 15 420 18.04 22.45 151.50 10-25 x 16 2 2RR 12 1/4 DSX113 204556 PDC 8 x 13 420 422 0.50 4.00 1.22 2-10 4 2RR2 12 1/4 DSX113 204556 PDC 8 x 13 1408 1714 16.54 18.50 119.09 25-35

Bit life

Grading

Rot Flow Press Inc Mud Total Total Total (RPM) (GPM) (psi) (deg) SG mtr hrs krevs I 0

O

D

Dull L B

G O

R

120

820

1450

1.07

405

18.04

152

0

1 WT A

E

I NO TD

60 120

680 820

1000 0.00 1.15 1900 1.00 1.19

2 308

0.50 17.04

1 120

0 1

1 WT S 3 WT A

X X

I CTBHA I PN TD

•BHA nb does not always = bit nb •Drilling time = bit time on bottom (← ← Mud loggers) •Krevs = 1000 bit revolution (← ← Mud loggers)

Drilling Parameters vs Bit Performance

Bit performance
Main function: ROP and longevity
Drilling fluid is circulated through passageways in the bit to remove cuttings and apply hydraulic power to improve ROP
ROP is a function of WOB, RPM, mud properties and hydraulic efficiency

Chip Formation
Tooth load overcomes rock compressive strength, generates crater
Scraping helps to remove chips from craters.

Cutter Borehole pressure causes chip hold down effect

Formation Courtesy of

ROP vs Overbalance Data based on 7-7/8” bit with 30 klbs at 60 RPM

Courtesy of

Chip Removal
Removal of chips is required to allow for new chip formation Hydraulics help to remove chips

Cutter

Formation 72

Courtesy of

WOB (Weight on Bit) Response

ROP

CHIP CREATION

0 0 Courtesy of

WEIGHT on BIT

CHIP REMOVAL

RPM Response

CHIP CREATION

ROP

CHIP REMOVAL

0 0 Courtesy of

RPM

Effects of Offset or Skew

Reduced Offset

Increased Offset

– 0º - 2º – Reduced Gage Scraping – More Durable – Slower Drilling – Abrasive / Hard Formations

– – – – –

Courtesy of

3º - 5º Increased Gage Scraping Less Durable Faster Drilling Soft / Sticky Formations

Cone Profiles

Flat Cone Profile – – – –

Minimum Bottom Scraping More Durable Slower Drilling Abrasive / Hard Formations

Round Cone Profile – – – –

Increased Bottom Scraping Less Durable Faster Drilling Soft / Sticky Formations

Tooth Cutter Design

Faster Drilling Less Durable

Slower Drilling More Durable

Insert Cutter Design HP51

Faster Drilling Less Durable

HP83

Slower Drilling More Durable

Cutting Structure Comparisons EHP41H

Faster Drilling Less Durable

HP83

Slower Drilling More Durable

Tooth & Insert Cutter Designs • • • • • •

Soft Formation

Hard Formation

Fewer Teeth Longer Teeth Bigger Teeth Sharper Teeth Sharp Profile Fracture-Resistant Tooth Material

• • • • • • •

• Faster Drilling • Less Durable

• •

More Teeth Shorter Teeth Smaller Teeth Duller Teeth Rounded teeth Flat Profile Wear-Resistant Tooth Material Slower Drilling More Durable

Bit Selection

Bit Application Spectrum

Penetration Rate

PDC

Mill Tooth Insert

Impreg & Natural Diamond

Formation Compressive Strength Courtesy of DP

Bit Selection Process

Which One ?

Courtesy of

Bit Selection - PDC Advantages
Very Fast ROP
Long Life Potential

Considerations
Impact Damage
Abrasiveness
Stability

Courtesy of

Bit Selection – Tooth Bit Advantages
Fast ROP
Good Stability
Economic

Considerations
Tooth Wear Rate
Bearing Life

Courtesy of

Bit Selection – Insert Bits Advantages
Cutting Structure Durability
Range of Formations
Interbed Tolerance
Steerability and Stability

Considerations
Slower ROP
Bearing Life Courtesy of

Bit Selection – Natural & Impreg Diamond Bits Advantages
Very Durable
Hard Rock Capability
Low Junk-in-Hole Risk

Considerations
Slower ROP
RPM Sensitivity
High Cost Applications Courtesy of

Gauging Procedures for 3-Cone Bits Smith 3-Cone Bits are designed to have minimum gauge contact. By use of suitable gauge cutting structure design and materials, the “minimum gauge” configuration improves penetration rates whilst maintaining full size hole. Only the cutting elements (teeth or inserts) contact, while the cone shell steel is held away from the hole wall. This means that unless the gauge cutting elements are “lined up” with the gauge contact point on any gauge ring, the bit will measure slightly smaller than it actually is. This is particularly true of aggressive insert bits which have a lighter set gauge and large offset. Gauging a 3-cone bit, either sharp or dull, requires some care and should be carried out as follows: Gap

1. Only use a calibrated 3-cone gauge ring measuring the nominal bit size. 2. Turn the bit on its pin and rotate all the cones to their “maximum gauge point” so that a gauge tooth or insert lines up at this point. 3. Place the gauge ring over the bit at the maximum gauge points. 4. Pull the ring gauge tight against the gauge elements on two cones. 5. Measure any gap at the free cone. This is not the the correct value for gauge wear. 6. To calculate the actual gauge wear you must multiply the gap distance by 2/3 (‘two thirds’). For example: if measured gap is 3/16” then multiply by 2/3 giving 2/16” under-gauge. 7. Record the bit as being either in gauge or the amount under-gauge. Although IADC say to use an “I” for in gauge, we recommend using a 0 (zero) to avoid the confusion between an I and a 1. Important points to note: A 3-Cone bit can be built larger than nominal size because of the plus tolerance allowed, but a new bit can never be undergauge (due to the required cutting structure clearances).

Maximum gauge point API Sizes for New Bits Bit Size

To gauge a new bit you must use a 3-cone ring gauge that measures the nominal bit size plus API tolerance (see table). You CANNOT use a PDC ring gauge to gauge a 3-cone bit and vice versa. On those Smith 3-Cone bits that feature the ‘OD’ diamond enhanced heel row inserts (e.g. MSDGHOD), these bits are designed and built so that these inserts actively cut gauge at the maximum gauge point. Therefore, if the gauge cutting elements are worn and undergauge, then regauge the bit on the heel row inserts. The manufacturing locations of Smith 3-Cone bits are all ISO Certified (ISO 9001).

API Roller Cone Bit Tolerances

Actual Size

Bit Size

Tolerance

26.094”

3-3/8” to 13-3/4”

+1/32”, -0”

23.000”

23.094”

14” to 17.5”

+1/16”, -0”

17.5”

17.500”

17.562”

17-5/8” and larger

+3/32”, -0”

16”

16.000”

16.062”

12.25”

12.250”

12.281”

8.5”

8.500”

8.531”

6”

6.000”

6.031”

Min.

Max.

26”

26.000”

23”

Gauging Procedures for PDC Bits Gauging a PDC bit, either sharp or dull, requires some care and should be carried out as follows: 1. Only use a calibrated PDC “No-Go” gauge ring. 2. Turn the bit on its pin. 3. Place the No-Go gauge ring over the bit - it should stop at the gauge skimmer/gauge pads 4. If the No-Go PDC gauge ring will not pass over the entire gauge area of the bit then the bit is in gauge. 5. If the No-Go gauge ring will pass then place the ring gauge at the gauge pads and pull hard to one side. 6. Measure the gap in 1/16” at the point opposite the point of contact between ring gauge and gauge pad. 7. Record the bit as being either in gauge or the amount under-gauge. Although IADC say to use an “I” for in gauge, we recommend using a 0 (zero) to avoid the confusion between an I and a 1.

No-Go gauge ring pulled hard against gauge pad.

PDC Bit No-Go ring gauge

Measure the gap here in 1/16” and record

Important points to note: A PDC bit can be built slightly smaller than nominal size because of the negative tolerance allowed, but a new bit should never be overgauge. To gauge a bit you must use a PDC “No-Go” ring gauge that measures the nominal bit size minus API tolerance (see table). You CANNOT use a 3-cone ring gauge to gauge a PDC bit and vice versa.

API PDC Bit Tolerances Bit Size

Tolerance

6 3/4” and smaller

-0.015” to + 0”

6 25/32” and including 9”

-0.020” to + 0”

9 1/32” and including 13 3/4”

-0.030” to + 0”

13 25/32” and including 17 1/2” -0.045” to + 0”

The manufacturing locations of Smith PDC bits are all ISO Certified (ISO 9001).

17 17/32” and larger

-0.063 to + 0”

Bi-center Bit Casing / Drift Diameter Bit Center

Bit Center Hole Center Drill Diameter

Pilot Diameter

Tripping through Casing / During Drill out

Drilling Ahead

Drill Out Mode
During drill out, drift & drill bits rotate around the drift axis
The drift axis is at the geometric center of the reamer

Drilling Ahead When drilling ahead, drift & drill bits rotate around the drill axis The drill axis is defined as the center of the pilot section, and is also the center of the bit connection / shank

Quad-D Nomenclature 12 1/4” x 14 3/4” QDS41PX Drift Diameter Drill Diameter

QDS: QUAD-D Steel Bit QDM: QUAD-D Matrix Bit QDG: QUAD-D Reamer

Enhanced Gage Protection (standard on all steel bits)

Number Range Cutter Size 02-07 6mm 08-27 9mm 28X 11mm 29-59 13mm 60-81 16mm 82-97 19mm 98X 22mm 99X 25mm

9 7/8”

8 1/2”

Drill Diameter Drift Diameter

Dual Diameter Reamer Geometry Pilot Conditioning Section Diameter

6 1/2”

Pilot Bit Diameter

8 1/2” x 9 7/8” QDG76 example Pilot Bit = 6 1/2” Diameter

= 6 3/4”