brocas iadc
TRANSCRIPT
Bits and HolemakingIPM
Bits and Holemaking
DRILLING PRACTICES
Bits and HolemakingIPM
IADC Bit Classification
Bits and HolemakingIPM
IADC Classification – Roller Cone
Ref: SPE 23937 The IADC Roller Bit Classification System
8-1/2” EHP 51
517G
Soft Formations w ith Low Compressive Strength and High
Drillability
1
Medium to Medium Hard Formations w ith
High Compressive Strength
2Hard Semi-Abrasive
and Abrasive Formations
3Soft Formations w ith Low Compressive Strength and High
Drillability
4
Soft to Medium Formations w ith Low
Compressive Strength5
Medium Hard Formations w ith High
Compressive Strength6
Hard Semi-Abrasive and Abrasive Formations
7Extremely Hard and
Abrasive Formations 8
INSERT BITS
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 Gauge
Protected
3Sealed Roller
Bearing4
Sealed Roller Brg -
Gauge Protected
5Sealed Friction Bearing
6Sealed
Frction Brg Gauge
Protected
7
Features Available (Optional)
A - Air ApplicationB - Special Bearing SealC - Center JetD - Deviation ControlE - Extended NozzlesG - Gauge/Body 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
Bits and HolemakingIPM
Soft
Hard
IADC CodesTooth
2
1
3
1-1
1-3
2-1
IPM
Bits and HolemakingIPM
Soft
Hard8
7
6
4
5
Tooth
Insert
IADC Codes
2
1
3
8-3
4-1
IPM
Bits and HolemakingIPM
Soft
Hard
1
8
7
6
4
5
Tooth
Insert
2
1
3
PDC
IADC Codes
IPM
Bits and HolemakingIPM
Soft
Hard 8
7
6
4
5
Tooth
Insert
Diamond
IADC Codes
2
1
3
PDC
IPM
Bits and HolemakingIPM
Soft
Hard
1
8
7
6
4
5
Tooth
Insert
2
1
3Impregnated
Diamond
IADC Codes
Diamond
PDC
IPM
Bits and HolemakingIPM
IADC Bit Dull Grading Code
Bits and HolemakingIPM
IADC Bit Dull Grading CodeThe 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.
INNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
Bits and HolemakingIPM
IADC Bit Dull Grading CodeINNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
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
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
IPM Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
IADC Bit Dull Grading CodeINNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
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
*BC - Broken ConeBF - Bond FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Fixed Cutter Bits Roller Cone Bits
Note that this is for the Primary dull characteristics.
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
Fixed Cutter – Main Wear Characteristics
NO WEAR(NO)
WORNCUTTER
(WT)
BROKENCUTTER
(BT)
LOSTCUTTER
(LT)
EROSION(ER)
POST OR STUD CUTTERS
NO WEAR(NO)
WORNCUTTER
(WT)
BROKENCUTTER
(BT)
LOSTCUTTER
(LT)
CYLINDERCUTTERS
BONDFAILURE
(BF)
BONDFAILURE
(BF)
Courtesy of
Bits and HolemakingIPM
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 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
Fixed Cutter Bits
BU - Balled Up
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Roller Cone Bits
Dull Characteristics – Some Examples
BT – Broken Teeth (primary)
CD – Cone Dragged (secondary)
Ref : IADC Drilling Manual – Eleventh Edition
Bits and HolemakingIPM
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 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
Fixed Cutter Bits
CT – Chipped Cutter
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
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 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
Fixed Cutter Bits
LT – Lost Cutter
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Roller Cone Bits
Dull Characteristics – Some Examples
BT – Broken Teeth/Cutters
Ref : IADC Drilling Manual – Eleventh Edition
Bits and HolemakingIPM
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 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
Fixed Cutter Bits
La
RO – Ring Out
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Roller Cone Bits
Dull Characteristics – Some Examples
JD – Junk Damage
Ref : IADC Drilling Manual – Eleventh Edition
Bits and HolemakingIPM
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 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
Fixed Cutter Bits
WT – Worn Cutters
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Roller Cone Bits
Dull Characteristics – Some Examples
SD - Shirttail Damage
Ref : IADC Drilling Manual – Eleventh Edition
Bits and HolemakingIPM
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Roller Cone Bits
Dull Characteristics – Some Examples
TR - Tracking
Bits and HolemakingIPM
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Roller Cone Bits
Dull Characteristics – Some Examples
SS – Self Sharpening Wear
Ref : IADC Drilling Manual – Eleventh Edition
Bits and HolemakingIPM
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Roller Cone Bits
Dull Characteristics – Some Examples
ER – Erosion
Ref : IADC Drilling Manual – Eleventh Edition
Bits and HolemakingIPM
IADC Bit Dull Grading CodeINNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
Fixed Cutter Bits Roller Cone Bits
C - Cone N - Nose T - Taper S - ShoulderG - Gauge
N - Nose RowM - Middle RowG - Gauge RowA - All Rows
Cone 1, 2 or 3
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
IADC Bit Dull Grading CodeINNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
Fixed Cutter Bits Roller Cone Bits
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 used, 8 - All life used, i.e., no bearing life remaining.)
Non Sealed Bearings
Sealed BearingsE - Seals EffectiveF - Seals FailedN - Not Able to Grade
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
IADC Bit Dull Grading CodeINNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
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
Bits and HolemakingIPM
IADC Bit Dull Grading CodeINNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
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
*BC - Broken ConeBF - Bone FailureBT - Broken Teeth/CuttersBU - 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
LN - Lost NozzleLT - Lost Teeth/CuttersOC - Off-Center WearPB - 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 * Show Cone under Location 4
Fixed Cutter Bits Roller Cone BitsThis is for the Secondary dull char. and it uses the same codes as for the Primary dull char.
Ref : Reed Hycalog PDC & Roller Cone Product Technology Reference Information
Bits and HolemakingIPM
IADC Bit Dull Grading CodeINNER ROWS
OUTERROWS
DULL CHAR
LOCA- TION
BRNG/ SEALS
GAUGE 1/16”
OTHER CHAR
REASON PULLED
Cutting Structure RemarksB G
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
Bits and HolemakingIPM
Key to Dull Bit Grading: Grade a Lot of Dulls !
Photo courtesy of
Bits and HolemakingIPM
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 R1 1 16 T11C L15264 115 3 x 18, 1
x 16 15 420 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 CTBHA4 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
Run Data Bit life Grading
To be filled up at wellsite
•BHA nb does not always = bit nb
•Drilling time = bit time on bottom ( Mud loggers)
•Krevs = 1000 bit revolution ( Mud loggers)
Bits and HolemakingIPM
Drilling Parameters vs Bit Performance
Bits and HolemakingIPM
DIFFERENTIAL PRESSURE AT BIT
Erosion
Depth of Cut
Wash out
Worn CuttersWOB
Flow Rate
Drilling Problem Identification
Bits and HolemakingIPM
CIRCULATING PRESSURE (standpipe pressure with bit off bottom)
Nozzles
Restriction
Wash out
PumpsMud Weight
Flow Rate
Mud Properties
Air in Mud
Drilling Problem Identification
Bits and HolemakingIPM
TORQUE
WOB
Hole Angle
Wash out
FormationMud Weight
Hole Cleaning
Mud Properties
Junk
Bit Related RPM
Reaming Dry Drilling
Drilling Problem Identification
Bits and HolemakingIPM
RATE OF PENETRATION
RPM/WOB
Hole Angle
Wash out
FormationOverbalance
Hydraulics
Bit RelatedJunk
Drilling Problem Identification
Bits and HolemakingIPM
Condition of Dull Bit Possible Causes Possible RemediesExcessive bearing wearExcessive rotary speed
Excessive rotating timeExcessive WOB
Excessive sand in circulating systemUn-stabilised drill collarsImproper bit type
Slower rotary speedReduced rotating hoursLighter WOB
Removal of sand from circulating fluidStabilise drill collars
Use harder formation bit type withstronger bearing structure
Excessive broken teethImproper bit typeImproper break-in procedure used
for new bitExcessive WOB for type used
Use harder formation bit type havingmore teeth
Proper break-in procedure used for newbit
Lighter WOBUnbalanced tooth wearImproper bit type
Improper break-in procedure usedfor new bit
Use of different bit type based upon therows of teeth which are excessively
worn on the dull bitProper break-in procedure used for new
bitExcessive tooth wear Excessive rotary speed
Improper bit typeUse of non hardfaced type
Slower rotary speedUse of harder formation bit type having
a greater number of teethUse of bit type having hardfaced teeth
Fluid cut teeth & coneExcessive circulation rate of fluidExcessive sand in circulating system
Reduction in circulation fluid rateRemoval of sand from circulation fluid
Excessivelyundergauge
Improper bit typeExcessive rotating time
Use of bit having greater gaugeprotection
Reduce rotating hoursSkidded due to balling Excessive WOB
Improper bit typeInsufficient fluid circulation rate
Lighter WOBUse of softer formation bit type having
teeth more widely spacedIncrease fluid circulation rate
ROLLER CONE BITSDrilling Problem Identification
Bits and HolemakingIPM
Condition of Dull Bit Possible Cause Possible RemediesPolished diamonds Rotating in a hard formation
without making holeAdd WOB or select a bit withsmaller diamonds/cutters
Shattered diamonds Improper stabilisationAbnormal vibrations
Improper handling
Correct the stabilisationReduce the vibration bychanging the RPMProper handling
Sheared diamonds Improper break-in,Broken nose stones
Clean bottom of hole,Correct break-in procedure
Burned (flattened)diamonds
Inadequate cooling Increase the circulation rate toimprove cooling
Burned bit Overheating as a result ofplugging and/or balling up
Take care of proper hydraulics
Heat checking of PDCsupports or bit body(matrix)
Overheating
Worn throat Fragments of hard formationrolling in the throat
Proper hydraulics
Loss of gauge Long intervals reamed withinsufficient cooling due toclogged junk slots
When reaming minimise RPMand bit weight
Junk damage Junk in hole just ahead of thefirst diamond bit used
Clean bottom on previous bitrun with a junk basket in the
string
FIXED CUTTER BITSDrilling Problem Identification
Bits and HolemakingIPM
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
Bits and HolemakingIPM
Cutting Structure ComparisonsHP83EHP41H
Faster DrillingLess Durable
Slower DrillingMore Durable
42
Tooth & Insert Cutter Designs Soft Formation
Fewer Teeth Longer Teeth Bigger Teeth Sharper Teeth Round Profile Fracture-Resistant
Tooth Material Faster Drilling Less Durable
Hard Formation
• More Teeth• Shorter Teeth• Smaller Teeth• Duller Teeth• Flat Profile• Wear-Resistant Tooth Material
• Slower Drilling• More Durable
43
Bits and HolemakingIPM
• Under no circumstances should the cutting structure of fixed cutter bit be allowed to contact any steel surfaces.
• All bits should be gauged with an appropriately sized gauge ring
• Bit serial number should be recorded, together with the bit type and diameter.
• Tricone bits should be made up to the drill string using a correctly sized bit breaker.
• Fixed cutter bits should be “walked” by hand before applying correct torque.
• Natural diamond bits, impregnated bits and TSP bits have a fixed TFA which can not be modified at the rig site.
Bit Handling and Make up
Bits and HolemakingIPM
Roller Cone BitsRunning in
• Make the bit up to proper torque.• Lower the bit slowly through ledges and dog legs
• Lower the bit slowly at liner tops• Roller cone bits are not designed for reaming. If reaming is required then it should be undertaken with light weight and low RPM
• Protect nozzles from plugging
Establish a bottom hole pattern• Rotate the bit and circulate when approaching bottom. This will prevent plugged nozzles and clear out hole fill.
• Lightly tag the bottom with low RPM.• Gradually increase the RPM.
• Gradually increase weight on WOB.
Before re-running green bits• Make sure the bit is in gauge.
• Check any bit for complete cutting structure.• Check any sealed bearing bit for effective seals.
• Soak any sealed bearing bit in water or diesel to loosen formation packed in the reservoir cap equalisation ports.• Re-grease l4¾" diameter and larger open bearing bits.
Bit Running Procedures
Bits and HolemakingIPM
Fixed Cutter BitsPREPARATION
• Before running a diamond bit into the hole, have a junk basket run on the previous bit.
• After the previous bit is pulled, inspect it for junk damage and other wear, then gauge it.
• If the previous bit appears OK, the bit may be prepared to be run into the hole.
• Check O-ring and install nozzles, if appropriate, using the correct nozzle spanner as supplied by the bit manufacturer.
• Check for cutter damage.
• Check that the bit is within tolerance on diameter and that there is no foreign material inside it.
Bit Running Procedures
Bits and HolemakingIPM
Fixed Cutter BitsRUNNING THE BIT (ROTARY ASSEMBLY)
• Handle the fixed cutter bit with care. DO NOT set the bit down without placing wood or a rubber pad beneath the diamond cutters.• A correct bit breaker should be used and the bit should be made up to the correct torque as determined by the pin connection size.• Care should be taken in running the bit through the rotary table and through any known tight spots. Hitting ledges or running through tight spots carelessly may damage the cutters or gauge.
• Reaming is not recommended, however, if necessary, pick up the string and run the maximum fluid possible. Rotate at about 60 RPM. Advance bit through tight spot with no more than 4000 pounds weight on bit (WOB) at any time.
• As hole bottom is approached, the last three joints should be washed down slowly at full flow and with 40 to 60 RPM to avoid plugging the bit with fill.• Once the bottom is located, the bit should be lifted just off bottom (0 to 1 foot if possible) and full volume circulated while slowly rotating for about 5 to 10 minutes.
• After circulating, ease back to bottom and establish the bottom hole pattern.• When ready to start drilling, increase the rotary speed to about 100 RPM and start cutting a new bottom hole pattern with approx. 1000 to 4000 pounds WOB.
• Cut at least one foot in this manner before determining optimum bit weight and RPM for drilling.• Determine optimum ROP by conducting a drill-off test.
Bit Running Procedures
Bits and HolemakingIPM
Fixed Cutter BitsRUNNING THE BIT (PDM or TURBINE)
• Start the pumps and increase to the desired flow rate when approaching bottom.
• After a short cleaning period, lower the bit to bottom and increase WOB slowly.
• After establishing a bottom hole pattern, additional weight may be slowly added.
• As weight is increased, pump pressure will increase, so the differential pressure and WOB must be kept within the recommended downhole motor specifications.
• drillpipe should be slowly rotated to prevent differential sticking.
• All other operating practices are as per standard practices.
Bit Running Procedures