Back to Low Alloy Medium Carbon QT
ML00159 - Mar.2020

Collapse of a Drill Pipe

Micrography of a longitudinal section of the pipe at the fracture position, in the thinner thickness. The diagonal line in the middle of the figure is the fracture surface and it is possible to identify that it was sheared with strong plastic deformation. The segregation bands (longitudinal lines) are deformed in the direction of the failure shearing, in a depth that is several milimeters deep in the pipe, from the fracture surface.

14

17
of a of the at the position, in the thinner thickness. The diagonal line in the middle of the figure is the surface and it is possible to identify that it was sheared with strong . The (longitudinal lines) are deformed in the direction of the failure shearing, in a depth that is several milimeters deep in the , from the surface.
M

Material

Low Alloy Medium Carbon QT
  • API 5D S135
  • AISI 4130
  • Modified
Ds

Description

The 5 7/8" has collapsed during operation due to lateral movement (). It broke during stretching, when it was removed from the well. The column was 2 years old and the pipe is ductile, typical of . The collapsed region is thicker (due to compression) and presented several plastically deformed (overloaded), and the rest of the fracture presented a ductile mechanism.

C

Chemistry (% in weight)

Pipe analysis

0.28C; 0.30Si; 0.56Mn; 0.015P; 0.006S; 0.95Cr; 0.006Ni; 0.48Mo.

Associated Images
Lateral image of a collapsed API 5D grade S135 drill pipe, presenting the fractured region (bottom of the figure) at the pipe body. Although the pipe steel is of a high strenght, the fracture characteristic is ductile, evidencing strong plastic deformation.
545
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Tempered martensite of the pipe body of this API 5D grade S135 drill pipe. The material presents, at this low magnification micrographic aspect, a slightly banded structure, usual for this type of drill pipe.
58
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrographic detail of the tempered martensite in the longitudinal section of the pipe body. Uniform structure.
44
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the tempered martensite in the longitudinal section of the pipe body.
39
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Martensite
Macroscopic view of the fracture in the pipe body. In the bottom of the figure, the fracture of the pipe shows a thicker thickness, revealing that this is the pipe region that was first damaged by bending (buckling). In the top of the figure, the fracture shows a (ductile) shearing mechanism and the thickness is thinner, as will be better observed in the macrography.
39
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - Fracture
Macrography of a longitudinal section of the pipe at the fracture position, as ground, showing in the rigth side the thicker thickness and several secondary cracks opened to the external side of the pipe (created during bending), and in the left side the shearing mechanism and the thinner thickness.
39
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Longitudinal Section AspectDf - Plastic Deformation
Macrography of a longitudinal section of the pipe at the fracture position, in the thicker thickness. The external side of the pipe (OD) is to the rigth side of the figure, and the internal side of the pipe is to the left of the figure. There are several secondary cracks, opened to the OD, created during bending.
37
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - NItal Etched MacroDf - Plastic Deformation
Macrography of a longitudinal section of the pipe at the fracture position, in the thinner thickness. The external side of the pipe (OD) is to the left side of the figure, and the internal side of the pipe is to the rigth of the figure. The fracture occurred by shearing the pipe in a single event (probably due to tensile stresses during removal).
37
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - NItal Etched MacroDf - Ductile Fracture
Macrographic detail of the longitudinal section of the pipe at the fracture position, in the thicker thickness. The several secondary cracks, opened to the OD, were created during bending and shows evidences of compression, responsible for the increase in the pipe thickness.
33
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - NItal Etched MacroDf - Ductile Fracture
Micrography of the longitudinal section of the pipe, at the thicker part of the fracture, showing several secondary cracks opened to the external side of the pipe. There are no problems in the material structure and the cracks are associated to large plastic deformation.
36
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Ductile Crack
Micrographic detail of the secondary cracks opened to the external side of the pipe. The cracks are associated to large plastic deformation.
30
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Ductile Crack
Micrographic detail of the ductile secondary cracks in the pipe body, close to the fracture. The strong plastic deformation is associated to the compression stresses generated by the buckling.
27
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Plastic Deformation
Macrographic detail of a longitudinal section of the pipe at the fracture position, in the thinner thickness. The external side of the pipe (OD) is to the left in the figure, and the internal side of the pipe is to the rigth in the figure. The fracture occurred by shearing the pipe in a single event (probably due to tensile stresses during removal).
24
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - NItal Etched MacroDf - Ductile Fracture
Micrography of a longitudinal section of the pipe at the fracture position, in the thinner thickness. The diagonal line in the middle of the figure is the fracture surface and it is possible to identify that it was sheared with strong plastic deformation. The segregation bands (longitudinal lines) are deformed in the direction of the failure shearing, in a depth that is several milimeters deep in the pipe, from the fracture surface.
17
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Ductile Fracture
Micrographic detail of sheared pipe, showing strong plastic deformation at the fracture. All the structure is deformed in the direction of the failure shearing.
17
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Plastic Deformation
Micrographic detail of sheared pipe, showing strong plastic deformation at the fracture. The structure shows the shear effect at the fracture.
15
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Martensite