Bits

CASING

Drilling Bits

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 gradingContractors) 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.the right operating parameters.

Well engineers must stay abreast of the latest developments to ensure optimum bit selection.

Bit TypesBit Types

Bit Types

Drill Bits

FixedCutter

RollerCone

InsertMill ToothDiamondP D C

NaturalDiamond

ImpregnatedDiamondT S P

RollerBearing

JournalBearing

Courtesy of

PDC (Polycrystalline Diamond Compact)

Drill Bits

FixedCutter

RollerCone

� Use artificially made diamonds

� Run successfully with downhole motors


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

PDC bit: Elements

1. synthetic diamond cutters

2. support structures for the cutters

3. gauge protection

1

3

2

5

2

Courtesy of

3. gauge protection inserts

4. Depth of cut limiters

5. nozzles.

Steel / Tungsten Carbide

PDC bit: Body Material

� Steel body in one piece

⇒ High precision⇒ simple repair⇒ no weld

� Tungsten Carbide matrix on steel shell

⇒ Erosion resistant

8 mm11 mm13 mm16 mm19 mm

PDC bit: Cutting Elements

BLADE

Courtesy of

PDC CUTTER

γγγγ

Natural Diamond

Drill Bits

FixedCutter

RollerCone


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Diamond Bit Profiles

Shallow coneParabolicTaper or Double cone

Soft formation=> => => => => 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� Smaller diamonds set in close pattern: hard formations

Natural Diamond bit: Elements

� Natural Diamonds = hardest mineral

� But brittle and Temp dependant

� Fluid circulation important

Courtesy of

� No cone , operates like a single unit

� Sensitive to shock and variation

TSP (Thermally Stable Polycrystalline)

Drill Bits

FixedCutter

RollerCone


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Cutting Elements - TSP

� TSP

Courtesy of

Impregnated Diamond

Drill Bits

FixedCutter

RollerCone


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Impregnated Diamond: Blades� Formation: medium

hard to very hard, ABRASIVE!

� Impregnated cutting element.

� Distributed in a tungsten carbide matrix.

Bit Blade Matrix

Courtesy of

matrix.� During heating

(furnace) the Segments are bonded to the bit body.

Diamond Grit

Cutting Elements - Impregnated

� Impregnated Diamond Blades

Courtesy of

ROLLER CONE

Alternative Names

Rock Bit

Drill Bits

FixedCutter

RollerCone

Rock BitTri-Cone™


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Basic Types Of Roller Cone Bits

Insert Bits

� Tungsten Carbide Bits

� Button Bits

Tooth Bits

� Mill Tooth Bits

Cone #3

Shirttail

Heel Row

Gauge Row

Cone #1

Cone #2

Inner Row

Nose

Roller Cone Components

Pin

Shirttail Lug

Bit Body

Nozzle

Roller cone bits: Nozzles

SHROUDEDTYPE

STANDARDTYPE

Mill Tooth Bits

Drill Bits

FixedCutter

RollerCone


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Cutting Elements – Mill Tooth

� Teeth and Hardfacing

Courtesy of

Insert Bits

Drill Bits

FixedCutter

RollerCone


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Cutting Elements - Insert

� Tungsten Carbide Inserts

Courtesy of

Tricone Bit - Roller Bearing

Drill Bits

FixedCutter

RollerCone


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Roller Cone Bearing Systems

Main Bearings Retention Bearings Seals

Journal Bearing

Bit

Roller Bearing

Bit

Tricone Bit - Roller Bearing

Retention Bearing

Main Bearing

Courtesy of

Thrust Bearing

Pin Bearing

Tricone Bit - Journal Bearing

Drill Bits

FixedCutter

RollerCone


NaturalDiamond


RollerBearing

JournalBearing

Courtesy of

Retention Bearing

Main Bearing

Tricone Bit - Journal Bearing

Thrust Bearing

Pin Bearing

Rock Failure MechanismsRock Failure Mechanisms

Failure Mechanisms

Failure Mechanisms

� Shear FailurePDC BITPDC BIT

CONTINUOUSCONTINUOUSSHEARINGSHEARING

� Compressive

ROLLER CONE BITCYCLIC COMPRESSION

� Compressive Failure

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 PDCShearing PDC

Ploughing / Grinding Natural/Impregnated Diamond

Courtesy of

IADC Bit ClassificationIADC Bit Classification

IADC Classification – Roller Cone517G

Soft Formations w ith Low Compressive Strength and High

Drillability

1

Medium to Medium Hard Formations w ith

High Compressive Strength

2

Hard Semi-Abrasive and Abrasive 3

STEEL TOOTH

BITS

Cutting Structure Series 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

Bearing/Gauge Description

Standard Roller

Bearing1

Roller Bearing Air

Cooled2

Roller Bearing 3

Features Available (Optional)

A - Air ApplicationB - Special Bearing SealC - Center JetD - Deviation ControlE - Extended NozzlesG - Gauge/Body Protection

Ref: SPE 23937 The IADC Roller Bit Classification System

8-1/2” EHP 51

and Abrasive Formations

3Soft Formations w ith Low Compressive Strength and High

Drillability

4

Soft to Medium Formations w ith Low Compressive Strength

5Medium Hard

Formations w ith High Compressive Strength

6Hard Semi-Abrasive

and Abrasive Formations

7Extremely Hard and Abrasive Formations 8

INSERT BITS

within the SeriesGauge

Protected

3

Sealed Roller

Bearing4

Sealed Roller Brg -

Gauge Protected

5

Sealed Friction Bearing

6Sealed

Frction Brg Gauge

Protected

7

ProtectionH - Horizontal Steering Appl.J - Jet DeflectionL - Lug PadsM - Motor ApplicationS - Standard Steel ToothT - Two Cone BitW - Enhanced Cutting StructureX - Predominantly Chisel Tooth InsertY - Conical Tooth InsertZ - Other Shape Insert

IADC Classification – Fixed Cutter

12-1/4” DS66H

M432Body Material Steel or Matrix.

Cutter Density PDC: 1 to 4, diamond bits: 6 to 8(the lower the number, the lighter set the bit).

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

Ref: SPE 23940 Development of a New IADC Fixed Cutter Drill Bit Classification System

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.

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.

Soft

IADC CodesTooth

2

1

1-1

Hard

2

31-3

2-1

Soft

4

Tooth

Insert

IADC Codes

2

14-1

Hard8

7

6

5

2

3

8-3

Soft

1

4

Tooth

Insert

2

1

PDC

IADC Codes

Hard 8

7

6

4

5

2

3

Soft

4

Tooth

Insert

IADC Codes

2

1

PDC

Hard8

7

6

4

5

Diamond

2

3

Soft

1

4

Tooth

Insert

2

1

IADC CodesPDC

Hard8

7

6

4

5

2

3Impregnated

Diamond

Diamond

IADC Bit Dull Grading CodeIADC 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 The methodology is composed of an 8 character code that describes bit wear and the reason why the bit was pulled.

INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED

Cutting Structure RemarksB G


INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED


Fixed Cutter Bits

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

Roller Cone Bits

0 1 2 3 4 5 6 7 8

Inner Cutting Structure (All Inner Rows)

Outer Cutting Structure (Gauge Row Only)

0 1 2 3 4 5 6 7 8

Cone 2Cone 3

Cone 1

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


INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED


BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion

*BC - Broken ConeBF - Bond FailureBT - Broken Teeth/CuttersBU - Balled Up Bit*CC - Cracked Cone

LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - Pinched BitPN - Plugged Nozzle/Flow Passage

Fixed Cutter Bits Roller Cone Bits

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

*CC - Cracked Cone*CD - Cone DraggedCI - Cone InterferenceCR - CoredCT - Chipped Teeth/CuttersER - ErosionFC - Flat Crested WearHC - Heat CheckingJD - Junk Damage*LC - Lost Cone

PN - Plugged Nozzle/Flow PassageRG - Rounded GaugeRO - Ring Out SD - Shirttail DamageSS - Self Sharpening WearTR - TrackingWO - Washed Out BitWT - Worn Teeth/CuttersNO - No Dull Characteristic

* Show Cone under Location 4

Note that this is for the Primary dull characterist ics.


Fixed Cutter – Main Wear Characteristics

NO WEAR(NO)

WORNCUTTER

(WT)

BROKENCUTTER

(BT)

LOSTCUTTER

(LT)

EROSION(ER)

POST OR STUDCUTTERS

BONDFAILURE

(BF)

NO WEAR(NO)

WORNCUTTER

(WT)

BROKENCUTTER

(BT)

LOSTCUTTER

(LT)

CYLINDERCUTTERS BOND

FAILURE(BF)

Courtesy of

Dull Characteristics – Some Examples

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

Fixed Cutter Bits

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


*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - Balled Up Bit*CC - Cracked Cone*CD - Cone DraggedCI - Cone Interference

LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - Pinched BitPN - Plugged Nozzle/Flow PassageRG - Rounded GaugeRO - Ring Out

Roller Cone Bits


CR - CoredCT - Chipped Teeth/CuttersER - ErosionFC - Flat Crested WearHC - Heat CheckingJD - Junk Damage*LC - Lost Cone

SD - Shirttail DamageSS - Self Sharpening WearTR - TrackingWO - Washed Out BitWT - Worn Teeth/CuttersNO - No Dull Characteristic

* Show Cone under Location 4BU – Balled Up Bit

(primary)CD – Cone Dragged

(secondary)Ref : IADC Drilling Manual – Eleventh Edition



Fixed Cutter Bits

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




Fixed Cutter Bits

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




Roller Cone Bits




* Show Cone under Location 4BT – Broken Teeth/Cutters

Ref : IADC Drilling Manual – Eleventh Edition



Fixed Cutter Bits


RO – Ring Out




Roller Cone Bits




* Show Cone under Location 4JD – Junk Damage




Fixed Cutter Bits


WT – Worn Cutters




Roller Cone Bits




* Show Cone under Location 4SD - Shirttail Damage




Roller Cone Bits





TR - Tracking



Roller Cone Bits




* Show Cone under Location 4SS – Self Sharpening Wear




Roller Cone Bits




* Show Cone under Location 4ER – Erosion



INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED



N - Nose RowM - Middle RowG - Gauge Row

Cone 1, 2 or 3

C - Cone N - NoseT - Taper S - ShoulderG - Gauge

G - Gauge RowA - All Rows



INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED



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

A linear scale estimating bearing life used. (0 -No life

Non Sealed Bearings

bearing life used. (0 -No life used, 8 - All life used, i.e., no bearing life remaining.)

Sealed Bearings

E - Seals EffectiveF - Seals FailedN - Not Able to Grade



INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

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 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.



INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED


BF - Bond Failure BT - Broken Cutters BU - Balled Up CT - Chipped Cutters ER - Erosion

*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - Balled Up Bit

LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - Pinched Bit

Fixed Cutter Bits Roller Cone BitsThis is for the Secondary dull char. and it uses the same codes as for the Primary dull char.

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 Bit*CC - Cracked Cone*CD - Cone DraggedCI - Cone InterferenceCR - CoredCT - Chipped Teeth/CuttersER - ErosionFC - Flat Crested WearHC - Heat CheckingJD - Junk Damage*LC - Lost Cone

PB - Pinched BitPN - Plugged Nozzle/Flow PassageRG - Rounded GaugeRO - Ring Out SD - Shirttail DamageSS - Self Sharpening WearTR - TrackingWO - Washed Out BitWT - Worn Teeth/CuttersNO - No Dull Characteristic




INNER ROWS

OUTERROWS

DULL CHAR

LOCA-TION

BRNG/ SEALS

GAUGE 1/16”

OTHER CHAR

REASON PULLED


For All Bits

BHA - Change Bottom Hole Assembly DMF - Down hole Motor Failure DSF - Drill String Failure

HP - Hole Problems HR - Hours PP - Pump Pressure 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

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


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

Photo courtesy of

BIT RECORD

Well : BIT RECORDDate :

Bit DataBHA Bit Size Bit type Serial IADC Nozzles Depth Depth Drilling ROP Bit krevs WOB Rot Flow Press Inc Mud Total Total Total DullNo. No. (inch) & maker Number Code (1/32") IN (m)OUT (m) Time (m/hr) (drilling) (Klbs) (RPM) (GPM) (psi) (deg) SG mtr hrs krevs I O D L B G O R

Run Data Bit life Grading

To be filled up at wellsite

No. No. (inch) & maker Number Code (1/32") IN (m)OUT (m) Time (m/hr) (drilling) (Klbs) (RPM) (GPM) (psi) (deg) SG mtr hrs krevs I O D L B G O R

1 1 16 T11C L15264 1153 x 18, 1

x 1615 420 18.04 22.45 151.50 10-25 120 820 1450 0 1.07 405 18.04 152 0 1 WT A E I NO TD

2 2RR 12 1/4 DSX113 204556 PDC 8 x 13 420 422 0.50 4.00 1.22 2-10 60 680 1000 0.00 1.15 2 0.50 1 0 1 WT S X I CTBHA

4 2RR2 12 1/4 DSX113 204556 PDC 8 x 13 1408 1714 16.54 18.50 119.09 25-35 120 820 1900 1.00 1.19 308 17.04 120 1 3 WT A X 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 PerformancePerformance

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 ROPROP

� 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.

CutterCutterCutterCutter

FormationFormation

Borehole pressure causes chip hold down effect

Courtesy of

ROP vs OverbalanceData 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

CutterCutter

Hydraulics help to remove chips

FormationFormation

CutterCutter

72 Courtesy of

CHIP CREATION CHIP REMOVAL

WOB (Weight on Bit) ResponseR

OP

WEIGHT on BIT0

0

Courtesy of

CHIP CREATION CHIP REMOVAL

RPM ResponseR

OP

RPM0

0

Courtesy of

Effects of Offset or Skew

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

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

Increased Offset

Courtesy of

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 DrillingLess Durable

Slower DrillingMore Durable

Insert Cutter Design

HP83HP51



Cutting Structure ComparisonsHP83EHP41H



Tooth & Insert Cutter Designs

Soft Formation

• Fewer Teeth• Longer Teeth• Bigger Teeth• Sharper Teeth

Hard Formation

• More Teeth• Shorter Teeth• Smaller Teeth• Duller Teeth• Sharper Teeth

• Sharp Profile• Fracture-Resistant Tooth

Material

• Faster Drilling• Less Durable

• Rounded teeth • Flat Profile• Wear-Resistant Tooth

Material

• Slower Drilling• More Durable

Bit SelectionBit Selection

Bit Application SpectrumP

enet

ratio

n R

ate

PDC

Mill ToothInsert

DP

Formation Compressive Strength

Pen

etra

tion

Rat

e

Insert

Impreg& NaturalDiamond

Courtesy of

Bit Selection Process

Which Which Which Which One ?One ?

Courtesy of

Bit Selection - PDC

Advantages� Very Fast ROP� Long Life Potential

ConsiderationsConsiderations� 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� Steerability and Stability

Considerations� Slower ROP� Bearing Life

Courtesy of

Bit Selection – Natural & ImpregDiamond 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 BitsSmith 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 isheld 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 willmeasure 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:

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

Gap

7. Record the bit as being either in gauge or the amount under-gauge. Although IADC say to usean “I” for in gauge, we recommend using a 0 (zero) to avoid the confusion between an I and a 1.

Maximum gauge point

API Sizes for New Bits API Roller Cone Bit Tolerances

Bit Size Actual Size Bit Size ToleranceMin. Max.

26” 26.000” 26.094” 3-3/8” to 13-3/4” +1/32”, -0”

23” 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”

Important points to note:

A 3-Cone bit can be built larger than nominal size because of the plustolerance allowed, but a new bit can never be undergauge (due to therequired cutting structure clearances).

To gauge a new bit you must use a 3-cone ring gauge that measures thenominal bit size plus API tolerance (see table). You CANNOT use a PDC ringgauge to gauge a 3-cone bit and vice versa.

On those Smith 3-Cone bits that feature the ‘OD’ diamond enhanced heel rowinserts (e.g. MSDGHOD), these bits are designed and built so that theseinserts actively cut gauge at the maximum gauge point.Therefore, if the gauge cutting elements are worn and undergauge, then re-gauge the bit on the heel row inserts.

The manufacturing locations of Smith 3-Cone bits are all ISO Certified (ISO9001).

Gauging Procedures for PDC Bits

Gauging a PDC bit, either sharp or dull, requires some care and should be carriedout 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/gaugepads4. If the No-Go PDC gauge ring will not pass over the entire gauge area of the bit then thebit is in gauge.5. If the No-Go gauge ring will pass then place the ring gauge at the gauge pads and pullhard to one side.6. Measure the gap in 1/16” at the point opposite the point of contact between ring gaugeand gauge pad.7. Record the bit as being either in gauge or the amount under-gauge. Although IADC say to

PDCBit

No-Go gauge ring pulledhard against gauge pad.

No-Go ring gauge

7. Record the bit as being either in gauge or the amount under-gauge. Although IADC say touse an “I” for in gauge, we recommend using a 0 (zero) to avoid the confusion between an Iand a 1.

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”

17 17/32” and larger -0.063 to + 0”

Important points to note:

A PDC bit can be built slightly smaller than nominal size because ofthe negative tolerance allowed, but a new bit should never beovergauge.

To gauge a bit you must use a PDC “No-Go” ring gauge that measuresthe nominal bit size minus API tolerance (see table). You CANNOTuse a 3-cone ring gauge to gauge a PDC bit and vice versa.

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

Measure the gap here in 1/16” and record

Casing /DriftDiameter

Drill Diameter

Hole Center

Bit Center Bit Center

Bi-center Bit

Tripping through Casing / During Drill out

Drilling Ahead

Diameter

Pilot Diameter

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

When drilling ahead, drift & drill bits rotate around the drill axis

The drill axis is defined as the center of the pilot section,

Drilling Ahead

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 Enhanced Gage Protection

Drill DiameterNumber Range Cutter Size

02-07 6mm08-27 9mm28X 11mm

29-59 13mm60-81 16mm82-97 19mm98X 22mm99X 25mm

QDS: QUAD-D Steel BitQDM: QUAD-D Matrix BitQDG: QUAD-D Reamer

Protection(standard on all steel bits)

Pilot Conditioning

Drift Diameter

Drill Diameter

Dual Diameter Reamer

Geometry

9 7/8”

8 1/2”

= 6 3/4”

Pilot Bit Diameter

Pilot Bit Diameter

Pilot ConditioningSection Diameter

8 1/2” x 9 7/8”QDG76 example

6 1/2”

= 6 3/4”

= 6 1/2”

Date post:	22-Oct-2014
Category:	Documents
Upload:	burt-powell
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