Kelly is designed to transfer the rotor torque to the drill string when drilling wells.
Kelly can be:
– Square section;
– Hexagonal section.
BASIC SIZES OF KELLY (SQUARE SECTION)
| Distance between faces, inch | Total length, ft |
| 2 1/2 | 37 |
| 3 | 37 |
| 3 1/2 | 37 |
| 4 1/4 | 37 |
BASIC SIZES OF KELLY (HEXAGONAL SECTION)
| Distance between faces, inch | Total length, ft |
| 3 | 37 |
| 3 1/2 | 37 |
