Drill Pipe Tips These common defects, their usual effects, probable causes and possible corrections, are listed in this chart to help Tuboscope customers recognize their drill pipe problems in time to do something about them.
Tube Body PROBLEM:
WASHOUT (Usually occurs near pin end upset taper or in area from lower part of slip area to box and upset taper) USUAL EFFECT:
Hole in pipe, drop in mud pressure, string separation, lost time PROBABLE CAUSE:
Surface notching, cyclic stressing, fatigue cracking POSSIBLE CORRECTION:
Minimize surface notching, reduce stress level, and avoid critical rotary speed. Move bottom-hole pipe up hole on trips, taper transition zone, use shock subs PROBLEM:
TWIST OFF (Usually occurs near pin end upset taper or in area from lower part of slip area to box end upset taper) USUAL EFFECT:
String separation, fishing job, lost time PROBABLE CAUSE:
Surface notching, cyclic stressing, fatigue cracking POSSIBLE CORRECTION:
Minimize surface notching, reduce stress level, avoid critical rotary speed. Move bottom-hole pipe up taper transition zone, use shock subs PROBLEM:
FATIGUE CRACKING (Predominately found near pin end upset taper and in an area from box end upset taper to lower part of slip area)
PROBLEM:
PROBLEM:
PROBLEM:
PROBLEM:
PROBLEM:
Surface Notching SLIP AREA MASH (Located in slip area)
NECKING (Usually located near either or both upsets)
BENT PIPE (Most often found in the slip area and center third of pipe body)
GALLED SHOULDERS
BELLED BOXES
Loss of shoulder seal, excessive shoulder to shoulder standoff, false make-up torque, unstable connection (wobble)
USUAL EFFECT:
USUAL EFFECT:
USUAL EFFECT:
stress
Reduced pipe O.D. / I.D., body wall thinning
PROBABLE CAUSE:
PROBABLE CAUSE:
Defective slip component, improper slip handling, excessive connection make-up or breakout, bending pipe in slips
Stuck pipe, over-pull (stretch), excessive hook load
Accelerated O.D. wear in pipe body and tool joints, vibration, high stress level, advanced fatigue
Surface impression, concentrator
POSSIBLE CORRECTION:
Improve slip/bowl maintenance, use care while setting sips. Consult API RP 7G for maximum height setting of tool joints above slips PROBLEM:
Surface Notching TONG CUTS (Usually located near pin and box end upsets)
POSSIBLE CORRECTION:
Place tongs only on tool joint, maintain tool joint diameter, use only correct long jaws, use sharp tong dies PROBLEM:
CHAIN CUTS (Usually found in an area over and just above pin end upset) USUAL EFFECT:
Circumferential grooves (notch) at pin end upset area, stress concentrators, cold worked metal PROBABLE CAUSE:
Excessive spinning; chain slip POSSIBLE CORRECTION:
Power change tension, consider use of power pipe spinner
POSSIBLE CORRECTION:
Dampen stress, avoid critical rotary speeds, minimize surface notching, move bottom-hole pipe up hole on trips, use shock subs, and prevent H2S in flow. Use lowest strength pipe where possible. Minimize rate of change in hole deviation PROBLEM:
Surface Notching CORROSION PITTING (General in location) USUAL EFFECT:
Bodywall loss, localized surface notch, stress concentration PROBABLE CAUSE:
Water, oxygen, CO2, salt, H2S, stress POSSIBLE CORRECTION:
Maintain mud PH above 9.5, use plastic coatings, inhibitors, oxygen scavenger, clean pipe I.D. & O.D., dampen stress, monitor with corrosion test rings PROBLEM:
Surface Notching SLIP CUTS (Located in slip area)
USUAL EFFECT:
Expanded O.D. /I.D. split pipe or tool joint Stuck pipe, internal explosion for back off POSSIBLE CORRECTION:
PROBABLE CAUSE:
Tongs placed on pipe, worn tool joints, improper tong jaws, poor handling
USUAL EFFECT:
PROBABLE CAUSE:
PROBLEM:
EXPANSION (Usually located above the pin and below the box which had been backed off)
PROBABLE CAUSE: USUAL EFFECT:
Multiple surface notches, stress concentrators
Washout, twist off, string separation, lost time, pipe loss Cyclic stressing, surface notches (corrosion, cuts, etc), hydrogen embrittlement
POSSIBLE CORRECTION:
Avoid sticking pipe, avoid overpull, consult API RP 7G for load limits per pipe class
PROBLEM:
Surface Notching RUBBER CUT EXTERNAL RING CORROSION (Usually found in an area approximately 2’ above pin end tool joint) USUAL EFFECT:
Circumferential concentrator
groove,
stress
PROBABLE CAUSE:
Corrosion / erosion at ends of drill pipe/ casing protectors– poor mud drain/ cleaning at protector end POSSIBLE CORRECTION:
Periodically move or remove protector, clean pipe at ends and under protector PROBLEM:
Surface Notching HAMMER MARKS (Usually found on tube in areas near the pin and box end tool joints) USUAL EFFECT:
Localized surface notch, cold worked metal PROBABLE CAUSE:
Tapping pipe to check fluid level on trip out POSSIBLE CORRECTION:
Use brass tipped hammer, tap pipe lightly
Avoid sticking pipe, minimize explosive force. Be sure explosive is placed in tool joint area, carefully inspect pipe before reuse PROBLEM:
COLLAPSE (Usually begins near tube center, often travels toward both ends)
Transverse surface notch, stress concentrator
SLIP AREA CRUSHING (Located in slip area)
PROBABLE CAUSE:
Pipe turning in slips, defective slips/bowl, improper slip handling POSSIBLE CORRECTION:
Use back-up tong for makeup and breakout, do not spin pipe with rotary, improve slip/bowl maintenance, use care while setting slips.
USUAL EFFECT:
Slip area O.D/ I.D. reduction, longitudinal splits in slip area, body wall thinning PROBABLE CAUSE:
Abrupt setting of slips, defective slip/ bowl maintenance, improper slips size POSSIBLE CORRECTION:
Stop pipe movement before setting slips, check slip-to-pipe fit, improve maintenance, and use only correct slip size
POSSIBLE CORRECTION:
Consult API RP 7G for maximum height setting of tool joints above slips, use both tongs, placed 90° apart, consult API RP RP 7G or the tool joint manufacturers recommendations for proper make-up torque per tool joint class, minimize breakout torques, minimize down-hole torques, use properly spaced stripping between pipe layers to minimize bending in storage or transit, avoid tough rough handling when moving pipe, use slings to winch pipe, avoid critical rotary speeds, avoid dropping string
USUAL EFFECT:
Tool Joint
Flattens tube, circulation block, string separation
WASHOUT
PROBLEM:
PROBABLE CAUSE:
USUAL EFFECT:
Excessive O.D. pressures, drill stem test, O.D. wear, I.D. erosion
Erosion of shoulder (face) seal and threads, mud pressure loss, string separation, lost time
POSSIBLE CORRECTION:
Consult API RP 7G or drill pipe manufacturers collapse charts per pipe class, minimize O.D. wear, keep pipe straight, and prevent I.D. erosion with plastic coating PROBLEM:
O.D. WEAR (Usually appears in center third of pipe body) USUAL EFFECT:
Body wall thinning, reduced tensile capacity, reduced cross section, reduced collapse resistance
PROBABLE CAUSE:
Leaking shoulder (face) seals, damaged shoulder (face) seals, insufficient make up torque, galled threads producing excessive shoulder standoff, shoulder fins rolled between seals, high spots on shoulder(false make-up torque), excessive shoulder removal by refacing, stretched pin threads, dirty threads and shoulders, misstabbing connection, improper jacking of stands in stand back area
PROBABLE CAUSE:
POSSIBLE CORRECTION:
Abrasive formations, bent pipe, deviated hole, high rotary speeds
Consult API RP 7G charts for proper make up torque per tool joint class, or tool joint manufacturer recommendations, remove shoulder damage by refacing. If possible, recut connection; remove shoulder fins by beveling shoulder; consult APIRP 7G, or tool joint manufacturers recommendations for maximum shoulder removal by refacing; keep thread protectors installed while picking up, laying down, handling, transporting, or storing pipe; clean threads and shoulder before make-up; use care when tripping pipe; use use only pipe pe jack tool with wide wide area contact.
POSSIBLE CORRECTION:
Straighten pipe, minimize ole deviation/rate of change, and avoid critical rotary speeds PROBLEM:
ID. EROSION (General location but often appears near upset areas) USUAL EFFECT:
Body-wall thinning, reduced cross-section, reduced tensile capacity, reduced collapse resistance PROBABLE CAUSE:
High velocity abrasion, sharp sand (solids), drilling, fluid turbulence, general corrosion POSSIBLE CORRECTION:
Plastic coating, minimize drilling fluid abrasives, inhibitors, minimize exposure to treating acids
USUAL EFFECT: PROBLEM:
PROBABLE CAUSE:
Bending in slips, setting tool joint too high above slips, improper tong/line geometry, no back up tong on makeup or breakout, poor transportation handling, dropping pipe on racks, critical rotary speeds, picking up pipe with winch line in center, improper drill collar weight
PROBLEM:
DRY OR MUDDY CONNECTION USUAL EFFECT:
Leaking shoulder (face) seals PROBABLE CAUSE:
Insufficient make-up torque, damaged shoulders (face) POSSIBLE CORRECTION:
Far East Inspection LocationsIndonesia Inspection: +62 (0)21 780 6265 Papua New Guinea Inspection: +62 (0)21 780 6265 Singapore Inspection: +65 6861 2688 Malaysia (Labuan) Inspection: +60 8 741 3020 Malaysia (Kemaman) Inspection: +60 9 863 1885 China (Shekou) Inspection: +86 755 2669 1915
Consult API-RP 7G or tool joint manufacturer recommendations for proper make-up torque per tool joint class, or, remove shoulder damage by refacing. If possible, recut connection; remove shoulder fins by beveling shoulder; consult API RP 7G, or tool joint manufacturer for maximum shoulder removal by refacing; keep thread protectors installed while picking up, laying down, handing, transporting, or storing pipe; clean threads and shoulder before make-up; use care when tripping pipe; use stabbing guide
USUAL EFFECT: USUAL EFFECT:
PROBABLE CAUSE:
Insufficient lubrication on shoulders, insufficient make-up torque, shoulder fins, high spots on shoulder POSSIBLE CORRECTION:
Apply rotary tool joint compound to shoulders when doping connection, remove shoulder fins by beveling shoulder, remove high spots by refacing, consult API-RP 7G or the tool joint manufacturers charts for proper make-up torques per tool joint class, use stabbing guide PROBLEM:
PIN BREAK (Cup type failure) USUAL EFFECT:
String separation, fishing job, lost time PROBABLE CAUSE:
Improper trip make-up torque, additional downhole make-up, improper type of lubricant producing excessive tension vs. make-up/torque POSSIBLE CORRECTION:
Consult API RP 7G charts or the tool joint manufacturer recommendations for proper make-up torque per tool joint class, minimize additional downhole make-up, use recommended rotary tool joint compound PROBLEM:
PIN BREAK (Flat fracture type failure) USUAL EFFECT:
String separation; fishing job, lost time PROBABLE CAUSE:
Pin wobble due to insufficient make-up, shoulder fins, false torque, fatigue cracking at thread root, galled threads POSSIBLE CORRECTION:
Consult API-RP 7G charts or the tool joint manufacturer recommendations for proper make-up torque per tool joint class, repair shoulder fins, use stabbing guide, repair galled threads PROBLEM:
PIN BREAK (Flat fracture type failure when torque and make-up are known to be satisfactory)
Distorted connection, loss of shoulder seal, will not mate properly with another connection, split body PROBABLE CAUSE:
Improper make up torque, additional down-hole make up, thin tool joints, improper thread lubricants POSSIBLE CORRECTION:
Maintain tool joint O.D., consult API RP 7G charts or tool joint manufacturer recommendations, for proper make up torque per tool joint class, minimize additional down-hole make up, use only recommended rotary tool joint compound, use stabbing guide, recut box PROBLEM:
STRETCHED PINS USUAL EFFECT:
Distorted connection, will not mate properly with another connection, possible pin break PROBABLE CAUSE:
Improper make-up torques, additional down-hole make-up, improper thread lubricant POSSIBLE CORRECTION:
Consult API RP 7G or tool joint manufacturer recommendations for proper make-up torques per tool joint class, minimize additional downhole make-up, use only recommend compound, use stabbing guide, recut pin PROBLEM:
GALLED THREADS USUAL EFFECT:
Damages mating threads, false torque, improper make-up, connection wobble, leaking shoulder seal, washout, pin break, drop string, lost time PROBABLE CAUSE:
Thread damage, handling without thread protectors, cross threading, worn threads, improper lubrication, dirty connection, defective kelly saver sub POSSIBLE CORRECTION:
Handle pipe only with thread protector, use care in stabbing and make-up, use stabbing guide, recut worn threads, use only recommended rotary tool joint compound, clean connections before use, repair or replace kelly saver sub PROBLEM:
SHOULDER FINS USUAL EFFECT:
Prevents shoulder make-up, false torque, leaking shoulder seal, wash-out, connection wobble, pin break, drop string, lost time
USUAL EFFECT:
String separation; fishing job, lost time PROBABLE CAUSE:
H2S, hydrogen embrittlement, excessive pin tension POSSIBLE CORRECTION:
Control H2S in flow, reduce stress level if possible, remove string from service for period of time, inspect tool joint threads PROBLEM:
WEAR (Thin shoulders) USUAL EFFECT:
Reduces torque capacity, belled boxes, reduced shoulder seat area PROBABLE CAUSE:
Crooked pipe, high rotary speeds, abrasive formations
PROBABLE CAUSE:
Mating tool joint with different O.D.’s, handling damage POSSIBLE CORRECTION:
Maintain tool joint O.D‘s if possible, remove fins by refacing and beveling, use stabbing guide, handle pipe only with thread protectors PROBLEM:
HEAT CHECKING USUAL EFFECT:
Time joint body cracking, washout, string separation lost time PROBABLE CAUSE:
Rapid heating due to friction between tool joint and formation, casing, whip stock, etc. high rotary speeds, rapid cooling POSSIBLE CORRECTION:
POSSIBLE CORRECTION:
Straighten pipe, reduce rotary speeds where possible, apply hard facing to box and pin end tool joints where possible
Reduce rotary speeds through tight areas; minimize tool- joint-toformation contact PROBLEM:
SHOULDER DAMAGE USUAL EFFECT:
Leaking shoulder seal, washout. String separation, lost time PROBABLE CAUSE:
Miss-stabbing connection, handling damage,, improper pipe jacking POSSIBLE CORRECTION:
Use care when tripping pipe, © Copyright NOV Tuboscope 2011
