Cross-over sub acts for conversion and connection of drill stem component in petroleum, natural gas and geology drilling work. It is used mainly for connecting of upper drill tools and lower drill tools during drilling operations.
Type a stand for same diameter: One crossover sub has one size (d)on o. D., code a.
Type b stands for reduce type: One crossover sub has two sizes (d1, d2) on o. D., code b.
Type c is left hand thread type: The connection thread is left hand type, code c.
The cross over sub in 4 types of main structure:
|
Sort |
Description |
Upper Connection Part |
Lower Connection Part |
Type |
|
1 |
Kelly cross-over sub |
Kelly |
Drill pipe |
A or B |
|
2 |
Drill pipe cross-over sub |
Drill pipe |
Drill pipe |
A or B |
|
3 |
Interim cross-over sub |
Drill pipe |
Drill collar |
A or B |
|
4 |
Drill collar cross-over sub |
Drill collar |
Drill collar |
A or B |
|
5 |
Drill bit cross-over sub |
Drill collar |
Drill bit |
A or B |
|
6 |
Swivel cross-over sub |
Swivel lower sub |
Kelly |
C |
|
7 |
Fishing cross-over sub |
Kelly |
Drill pipe |
C |
|
Drill pipe |
Fishing tools |
C |