Drilling string sub is made of high-strength alloy constructional steel and processed by heat treatment.
Its structure is suitable to the connected drilling string and the Sub connections at the both
ends are up to API standard. It is mainly used for conversion and connection of the drilling string
components in oil, natural gas operation.
Applicable documents: SY/T5200-2002 API Spec7
the type and main parameter of Drilling String Sub
|
No |
Class |
Type |
|
|
|
one |
Kelly Sub |
A or B |
Kelly |
Tool Joint |
|
two |
Special Drill-Stem Sub |
A or B |
Tool Joint |
Tool Joint |
|
three |
Crossover Sub |
A or B |
Tool Joint |
Drill Collar |
|
four |
Drill Collar Sub |
A or B |
Drill Collar |
Drill Collar |
|
five |
Bit Sub |
A or B |
Drill Collar |
Bit |
|
six |
Swivel Sub |
C |
Swivel Sub |
Kelly |
|
seven |
Fishing Crossover Sub |
C |
Kelly |
Tool Joint |
|
C |
Tool Joint |
Fishing Tool |
