A significant flare to the box torque shoulder can be an indication of possible connection over torquing which could result in belled boxes or stretched pins.
A dark ring around the outer edge of the tool joint shoulders (sealing-surface) can be an indication of under torqued connections. Under torqued connections contribute to “wobble”
between pin and bow tool joints causing excessive thread flank wear, galling and possible cracking in the pin threads.
Shorter than normal tool joint length is usually indicative of “re-worked” threads and torque shoulder. Logic dictates that minimum length of the non-hardbanded surface should be somewhat longer that the longest tong die used.
Check general appearance of tong die marks on the pin and box tool joint body. A significant absence of tong die marks on the box tool joint is indicative of the use of only one (1) tong during make-up and break out operations. That practice can cause deep transverse scars in the slip area or result in under torque connections.
Excessively deep tong die marks can be indicative of over torquing or hard to break connections. Raised metal, resulting from excessively deep tong die marks can contribute to casing wear.
Tool Joint Hardfacing (Hardbanding)
Chrome alloy or palletized tungsten carbide hardfacings are frequently applied to tool joint boxes to enhance wear resistance.
Hardfacings typically applied to new tool joints, at the manufacturing plant, are typically applied 3/32” proud (raised) to the outside of tool joint surface.
Careful, but, objective consideration should be given to the presence of hardfaced tool joints and possible casing wear. Smooth or field worn hardfacings do less damage to the casing than hardfacings with a rough finish.
Obviously, hardfaced tool joints are intended to be run in open hole where the tool joint works against the surface of the well bore.
Tool Joint Welding Date
Check the tool joint welding date stamps located on the pin base adjacent to the torque shoulder. See API RP7G-2 for the information available for this procedure.
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A Guide to Users Visual Examination of Drill Pipe Cont…
Tool Joint Mill Slot and Groove Marking
Compare the mill slot and groove markings with API RP7G-2 illustrations to confirm drill pipe weight and grade. Be aware, however, that such markings are not standardized in the industry.
Thread Protectors
Check for presence of tool joint thread protectors. Absence of protectors may be indicative of damaged tool joint threads and shoulders.
Tube Body Outside Surface
When rolling several lengths of drill pipe to check straightness, observe the general outside condition of the tube body. Look for deep transverse cuts in the slip area, mashes at any location, or evidence of sharp notches anywhere on the surface.
Outside surface pitting on drill pie is uncommon unless the pipe has been stored in humid climates. If outside surface pitting is present, it is usually more evident within the outer one third (1/3) of the tube length at each end.
If the pipe has drill pipe/casing protectors installed, or shows evidence of protectors having once been installed, check carefully for corrosion damage on the pipe surface where the protector would normally be positioned.
Tube Body Inside Surface
Use a bright light to observe the inside surface of several drill pipe lengths.
Look for heavy mud scale deposits. Thick, dried mud scale flaking from the tube surface can plug small jet nozzles. Mud scale on the pipe surface tends to retain moisture and
accelerates corrosion pitting damage.
Most drill pipe is internally plastic coated to reduce damage to the I.D. surface from corrosion pitting.
Presence of plastic coating, in good condition, helps reduce accumulation of mud scale.
Plastic coating generally has a slick, shiny finish and its condition is relatively easy to evaluate with a bright light.
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A Guide to Users Visual Examination of Drill Pipe Cont…
The corrosion control is reasonable if between 70% to 80% of the tube surface between opposite upset runouts is covered with well-bonded plastic coating.
Large sections of dis-bonded coating not only reduce the percent of surface protection but flaking coating can be a plugging concern.
It is difficult to accurately evaluate inside surface pitting damage, in drill pipe, by visual examination from the pipe end. Presence of coating or mud scale tends to hide the pitted condition. If heavy scale is present, or if pitting can be seen, a more thorough inspection should be performed.
Other Helpful Information
If drill pipe has been exposed to severe hydrogen sulfide (H2S) the surface of the pipe will sometimes have a dark green to black color appearance a few days after exposure.
Ask for information about performance history of the string. Sometimes good data is kept regarding accumulated footage drilled, rotating hours, and failure and damage records, etc.
Determine when drill pipe was last inspected and what type of inspection services, and specifications were applied.
Match the inspection report documents with the pipe in question. The report should reflect when the inspection was performed and the number of lengths serviced. Corresponding length numbers and service date markings are steel die stenciled on the pin end tool joint 35°
taper adjacent to the upset and should match information on the inspection report.
NOV Tuboscope Drilling Services 2011 www.tuboscope.com 1-713 799-5100 [email protected]