Work Instruction (Used Drill Pipe Coating) - NOV
Content
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 1
of 17
WORK INSTRUCTION
SCOPE:
To provide a general guideline for evaluating the condition of internal plastic
coatings in used drill pipe.
RECOMMENDATIONS:
1. Pipe to be visually inspected shall be cleaned internally, preferably with high
pressure water jetting equipment. Removal of drilling mud, chemical
residues, dust and dirt, and other visible contaminants is required. Debris
generated from the water blast step should be visually inspected to see if any
coating became disbonded during the process.
NOTE:
Water Blast should not exceed 15,000psi pressure. Recommend
use of a commercially available 360° nozzle. Do not use a pencil
point nozzle.
2. The pipe I.D. is dried with compressed air to remove residual water prior to
visual inspection.
3. To help determine fitness for purpose, Classes 1, 2, 3, and 4 have been
established to provide guidelines for evaluating the condition of the coating.
4. Several tools will be needed to perform the coating inspection:
a. High intensity light (alternatively, a mirror can be used to capture the
sunlight if the evaluation is taking place outside and there is a
sufficient amount of sun)
b. A hinged mirror capable of extending into the ID of the pipe for a
visual evaluation of the internal upset run-out
c. A knife to be used to test the adhesion around areas of damaged
coating
5. Photographs showing the varying conditions of the Classifications are
recommended for training inspectors and can be used to assist in decisions.
The classifications are broken down further by three areas of concern within
the drill pipe: (1) the tool joint, (2) the upset run-out, and (3) the tube body.
The effects of corrosion are more severe in the upset run-out area as well as
the tube body. The tube body is the part of the pipe that has the thinnest steel
and will therefore see a corrosion pit or body wall loss failure first. The upset
run-out, while having areas of thicker steel than the tube body, is the area that
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 2
of 17
WORK INSTRUCTION
sees much higher stress due to the several changes in geometry. A pit in the
upset run-out is a starting point of a stress crack which can then lead to a
wash-out. For these reasons, more concern is taken with minimal coating
damage in these areas.
6. Coating loss in the tool joint, up to 100%, is not always in and of itself
sufficient reason for down grade. However, if coating loss in tool joint is
creeping into the “run out” area, this area needs to be thoroughly evaluated for
coating adhesion as outlined in this guide.
7. The benefits of a comprehensive used drill pipe coating inspection program
are to ultimately extend the useful life of the pipe and prevent premature
failures caused by pitting type corrosion in the critical transition area (weld
line and internal upset area).
PICTORIAL DESCRIPTION OF DEFECTS
Figure 1: Blistered Coating
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 3
of 17
WORK INSTRUCTION
Figure 2: Coating Delaminating (Peeling) away from an area of damage
Figure 3: Wireline Cuts in Coating
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 4
of 17
WORK INSTRUCTION
CLASSIFICATIONS:
CLASS 1 (Premium)
Description:
STATUS:
•
Re-use
For the ID coating to achieve a class 1 (premium) designation it can
contain:
o Minor abrasion and scrapes down the tube and in the critical
transition area. The metal substrate cannot be exposed in any of
the areas of abrasion.
o No corrosion products (rust or scale) are present in the tube or
transition area.
o I.D. Coating is not blistering or delaminating (peeling off).
Figure 4: Class 1 (Premium) in the Tool Joint
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 5
of 17
WORK INSTRUCTION
Figure 5: Class 1 (Premium) in the Upset Run-out
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 6
of 17
WORK INSTRUCTION
Figure 6: Class 1 (Premium) in the Tube Body.
Figure 7: Internal camera view of Class 1 coating in the tube body
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 7
of 17
WORK INSTRUCTION
CLASS 2
STATUS:
Re-use
Description:
•
•
•
•
•
Wireline and tool damage to the coating in the tooljoints is normal and
acceptable to a 25% loss of coating film. Using a knife, test the
adhesion of the coating around the area of damage to ensure that
significant coating undercreep is not present. If undercreep is present,
take measures to remove loosely adhered coating
The I.D. coating in the tube body and the upset run-out contains
limited wire line cuts and tool damage.
Presence of surface corrosion (rust) is visible, but no significant pitting
is present. In addition, there should be no serious underfilm
(undercreep) corrosion present. This can be determined by using a
knife to pry at the coating around the area of damage. Coating
removed from this area that has evidence of rust attached to the
underside of the coating is evidence of underfilm corrosion. If
underfilm corrosion is present, this joint will be downgraded to a
minimum of Class 3.
Overall there can be coating loss of 5% or less in the tube body (with
no more than 3% being confined to one area). In the upset run-out,
limited cuts and scrapes can be present, but there is minimal coating
loss in this area (less than 2%). In the areas of coating loss, there
should be no evidence of corrosion pitting taking place. If need be use
a Boroscope to more closely evaluate coating condition in the tube
body.
Even though there are areas of mechanical damage down to the metal
substrate, the coating shows no signs of blistering or delaminating
(peeling off). As with the determination of underfilm corrosion,
coating delamination can be determined by obvious peeling of the
coating around areas of damage or by the use of a knife to check
adhesion around the area of damage. Coating that is easily removed
constitutes delamination.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 8
of 17
WORK INSTRUCTION
Figure 8: Class 2 Coating in the Tool Joint
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 9
of 17
WORK INSTRUCTION
Figure 9: Damage caused during the re-hardbanding of used drill pipe can lead to coating degradation, but in the tool
joint, coating loss is less of a concern
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 10
of 17
WORK INSTRUCTION
Figure 10: Class 2 Internal Up-set Run-out. Note the damage in the tool joint coating bleeding into the upset-runout.
Figure 11: Class 2 Tube Body. Note pinhole areas of coating damage and minor indication of rust on the left.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 11
of 17
WORK INSTRUCTION
CLASS 3
STATUS:
Re-use/Re-coat
Description:
•
•
•
•
•
•
The I.D. coating in the tube body contains wireline cuts and tool
damage.
Underfilm corrosion is present but physical removal is not severe and
only exposes a minimal amount of steel.
Coating loss is 15% or less in the tube body (with no more than 8%
confined to one area of the pipe).
Damage to the transition area (upset run-out) is observed but coating
loss is less than 15% and the onset of pitting type corrosion has not yet
occurred.
I.D. coating is not blistering or delaminating (peeling off). Coating
that is blistered or showing signs of delamination will automatically
downgraded to Class 4.
Damage to the coating in the tooljoints is normal and coating loss of
up to 60% is acceptable. Ensure that coating showing signs of
delamination are added to the lost coating to generate an accurate
percentage of coating damage.
NOTE:
Re-use of this pipe in normal drilling operations is acceptable. However, the
coating should be re-inspected after each well drilled or completed.
NOTE:
Re-coating of this class pipe should be considered in deep, high temperature, high
pressure wells (especially directional wells) with significant amounts of CO2
and/or H2S, or for use in workover/completion operations.
NOTE:
Water Blast can be used to dislodge any coating that may have been loosened due
to long term exposure to the environment.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 12
of 17
WORK INSTRUCTION
Figure 12: Class 3 Tool Joint. Note that the coating has been breached in several areas, but there is no peeling.
Figure 13: Class 3 - Damage to the upset run-out viewed with a hinged mirror
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 13
of 17
WORK INSTRUCTION
Figure 14: Class 3 Tube Body. Note the several areas of coating loss down to bare steel, there is
no peeling of the coating in those areas.
CLASS 4
STATUS:
Re-coat
Description:
•
•
Moderate to severe coating damage in the tube body and transition
area with severe underfilm corrosion observed during the adhesion
testing at areas of coating damage.
Coating loss in the tube body is 16% or more with the onset of pitting
corrosion.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 14
of 17
WORK INSTRUCTION
•
•
•
NOTE:
Coating loss in the transition area is 16% or more with the onset of
pitting corrosion.
I.D. coating shows evidence of blistering and delamination (peeling).
Up to complete tool joint coating loss.
100% loss of coating in the tool joint is not an immediate rejection. Further
evaluation of the upset runout and tube body should be the final determining
factor on the rejection of a joint.
Figure 15: Class 4 Tool Joint. Note the extensive loss of internal coating and the presence of pitting corrosion
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 15
of 17
WORK INSTRUCTION
Figure 16: The presence of blisters indicates coating degradation which can be caused by excessive temperature,
chemical exposure, and/or the coating reaching the end of its useful life
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 16
of 17
WORK INSTRUCTION
Figure 17: Class 4 Internal Upset Run-out. Note the extensive loss of coating, the presence of underfilm corrosion
and the presence of pitting corrosion.
Figure 18: Coating damage in the tool joint that propagates from the tool joint, through the upset run-out and into the
tube body leading to a Class 4 rating
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 17
of 17
WORK INSTRUCTION
Figure 19: Class 4 Tube Body. Note the peeling of the coating around the areas of damage and the blistering
beginning to form.
Figure 20: Delamination of the coating in the tube body automatically drops the joint to a Class 4
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 1
of 17
WORK INSTRUCTION
SCOPE:
To provide a general guideline for evaluating the condition of internal plastic
coatings in used drill pipe.
RECOMMENDATIONS:
1. Pipe to be visually inspected shall be cleaned internally, preferably with high
pressure water jetting equipment. Removal of drilling mud, chemical
residues, dust and dirt, and other visible contaminants is required. Debris
generated from the water blast step should be visually inspected to see if any
coating became disbonded during the process.
NOTE:
Water Blast should not exceed 15,000psi pressure. Recommend
use of a commercially available 360° nozzle. Do not use a pencil
point nozzle.
2. The pipe I.D. is dried with compressed air to remove residual water prior to
visual inspection.
3. To help determine fitness for purpose, Classes 1, 2, 3, and 4 have been
established to provide guidelines for evaluating the condition of the coating.
4. Several tools will be needed to perform the coating inspection:
a. High intensity light (alternatively, a mirror can be used to capture the
sunlight if the evaluation is taking place outside and there is a
sufficient amount of sun)
b. A hinged mirror capable of extending into the ID of the pipe for a
visual evaluation of the internal upset run-out
c. A knife to be used to test the adhesion around areas of damaged
coating
5. Photographs showing the varying conditions of the Classifications are
recommended for training inspectors and can be used to assist in decisions.
The classifications are broken down further by three areas of concern within
the drill pipe: (1) the tool joint, (2) the upset run-out, and (3) the tube body.
The effects of corrosion are more severe in the upset run-out area as well as
the tube body. The tube body is the part of the pipe that has the thinnest steel
and will therefore see a corrosion pit or body wall loss failure first. The upset
run-out, while having areas of thicker steel than the tube body, is the area that
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 2
of 17
WORK INSTRUCTION
sees much higher stress due to the several changes in geometry. A pit in the
upset run-out is a starting point of a stress crack which can then lead to a
wash-out. For these reasons, more concern is taken with minimal coating
damage in these areas.
6. Coating loss in the tool joint, up to 100%, is not always in and of itself
sufficient reason for down grade. However, if coating loss in tool joint is
creeping into the “run out” area, this area needs to be thoroughly evaluated for
coating adhesion as outlined in this guide.
7. The benefits of a comprehensive used drill pipe coating inspection program
are to ultimately extend the useful life of the pipe and prevent premature
failures caused by pitting type corrosion in the critical transition area (weld
line and internal upset area).
PICTORIAL DESCRIPTION OF DEFECTS
Figure 1: Blistered Coating
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 3
of 17
WORK INSTRUCTION
Figure 2: Coating Delaminating (Peeling) away from an area of damage
Figure 3: Wireline Cuts in Coating
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 4
of 17
WORK INSTRUCTION
CLASSIFICATIONS:
CLASS 1 (Premium)
Description:
STATUS:
•
Re-use
For the ID coating to achieve a class 1 (premium) designation it can
contain:
o Minor abrasion and scrapes down the tube and in the critical
transition area. The metal substrate cannot be exposed in any of
the areas of abrasion.
o No corrosion products (rust or scale) are present in the tube or
transition area.
o I.D. Coating is not blistering or delaminating (peeling off).
Figure 4: Class 1 (Premium) in the Tool Joint
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 5
of 17
WORK INSTRUCTION
Figure 5: Class 1 (Premium) in the Upset Run-out
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 6
of 17
WORK INSTRUCTION
Figure 6: Class 1 (Premium) in the Tube Body.
Figure 7: Internal camera view of Class 1 coating in the tube body
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 7
of 17
WORK INSTRUCTION
CLASS 2
STATUS:
Re-use
Description:
•
•
•
•
•
Wireline and tool damage to the coating in the tooljoints is normal and
acceptable to a 25% loss of coating film. Using a knife, test the
adhesion of the coating around the area of damage to ensure that
significant coating undercreep is not present. If undercreep is present,
take measures to remove loosely adhered coating
The I.D. coating in the tube body and the upset run-out contains
limited wire line cuts and tool damage.
Presence of surface corrosion (rust) is visible, but no significant pitting
is present. In addition, there should be no serious underfilm
(undercreep) corrosion present. This can be determined by using a
knife to pry at the coating around the area of damage. Coating
removed from this area that has evidence of rust attached to the
underside of the coating is evidence of underfilm corrosion. If
underfilm corrosion is present, this joint will be downgraded to a
minimum of Class 3.
Overall there can be coating loss of 5% or less in the tube body (with
no more than 3% being confined to one area). In the upset run-out,
limited cuts and scrapes can be present, but there is minimal coating
loss in this area (less than 2%). In the areas of coating loss, there
should be no evidence of corrosion pitting taking place. If need be use
a Boroscope to more closely evaluate coating condition in the tube
body.
Even though there are areas of mechanical damage down to the metal
substrate, the coating shows no signs of blistering or delaminating
(peeling off). As with the determination of underfilm corrosion,
coating delamination can be determined by obvious peeling of the
coating around areas of damage or by the use of a knife to check
adhesion around the area of damage. Coating that is easily removed
constitutes delamination.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 8
of 17
WORK INSTRUCTION
Figure 8: Class 2 Coating in the Tool Joint
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 9
of 17
WORK INSTRUCTION
Figure 9: Damage caused during the re-hardbanding of used drill pipe can lead to coating degradation, but in the tool
joint, coating loss is less of a concern
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 10
of 17
WORK INSTRUCTION
Figure 10: Class 2 Internal Up-set Run-out. Note the damage in the tool joint coating bleeding into the upset-runout.
Figure 11: Class 2 Tube Body. Note pinhole areas of coating damage and minor indication of rust on the left.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 11
of 17
WORK INSTRUCTION
CLASS 3
STATUS:
Re-use/Re-coat
Description:
•
•
•
•
•
•
The I.D. coating in the tube body contains wireline cuts and tool
damage.
Underfilm corrosion is present but physical removal is not severe and
only exposes a minimal amount of steel.
Coating loss is 15% or less in the tube body (with no more than 8%
confined to one area of the pipe).
Damage to the transition area (upset run-out) is observed but coating
loss is less than 15% and the onset of pitting type corrosion has not yet
occurred.
I.D. coating is not blistering or delaminating (peeling off). Coating
that is blistered or showing signs of delamination will automatically
downgraded to Class 4.
Damage to the coating in the tooljoints is normal and coating loss of
up to 60% is acceptable. Ensure that coating showing signs of
delamination are added to the lost coating to generate an accurate
percentage of coating damage.
NOTE:
Re-use of this pipe in normal drilling operations is acceptable. However, the
coating should be re-inspected after each well drilled or completed.
NOTE:
Re-coating of this class pipe should be considered in deep, high temperature, high
pressure wells (especially directional wells) with significant amounts of CO2
and/or H2S, or for use in workover/completion operations.
NOTE:
Water Blast can be used to dislodge any coating that may have been loosened due
to long term exposure to the environment.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 12
of 17
WORK INSTRUCTION
Figure 12: Class 3 Tool Joint. Note that the coating has been breached in several areas, but there is no peeling.
Figure 13: Class 3 - Damage to the upset run-out viewed with a hinged mirror
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 13
of 17
WORK INSTRUCTION
Figure 14: Class 3 Tube Body. Note the several areas of coating loss down to bare steel, there is
no peeling of the coating in those areas.
CLASS 4
STATUS:
Re-coat
Description:
•
•
Moderate to severe coating damage in the tube body and transition
area with severe underfilm corrosion observed during the adhesion
testing at areas of coating damage.
Coating loss in the tube body is 16% or more with the onset of pitting
corrosion.
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 14
of 17
WORK INSTRUCTION
•
•
•
NOTE:
Coating loss in the transition area is 16% or more with the onset of
pitting corrosion.
I.D. coating shows evidence of blistering and delamination (peeling).
Up to complete tool joint coating loss.
100% loss of coating in the tool joint is not an immediate rejection. Further
evaluation of the upset runout and tube body should be the final determining
factor on the rejection of a joint.
Figure 15: Class 4 Tool Joint. Note the extensive loss of internal coating and the presence of pitting corrosion
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 15
of 17
WORK INSTRUCTION
Figure 16: The presence of blisters indicates coating degradation which can be caused by excessive temperature,
chemical exposure, and/or the coating reaching the end of its useful life
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 16
of 17
WORK INSTRUCTION
Figure 17: Class 4 Internal Upset Run-out. Note the extensive loss of coating, the presence of underfilm corrosion
and the presence of pitting corrosion.
Figure 18: Coating damage in the tool joint that propagates from the tool joint, through the upset run-out and into the
tube body leading to a Class 4 rating
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
EFFECTIVE DATE
08/09/10
USED DRILL PIPE –
INTERNAL PLASTIC COATING CLASSIFICATIONS
PAGE 17
of 17
WORK INSTRUCTION
Figure 19: Class 4 Tube Body. Note the peeling of the coating around the areas of damage and the blistering
beginning to form.
Figure 20: Delamination of the coating in the tube body automatically drops the joint to a Class 4
This coating evaluation procedure is an uncontrolled document from NOV Tuboscope and may be used without
permission.
Copyright NOV Tuboscope. 2009. All Rights Reserved.
