It’s a needed tool when drilling with a wire line system, since it is the mechanism that allows the extraction of core barrel inner tube from the bottom of the hole to the surface.
It allows also descent the inner tube in dry drilling conditions.
On one end, is attached to the rig speed winch by a cable and at the other end carries a “lifting dogs” that fit into the “spearhead” of the inner tube, allowing its unlocking and its ascent to the surface.
The Overshot of TECSO, S.A. incorporates some advantages over conventional overshots:
- Union of the Overshot to the cable more functional.
- Safety system that allows also descent the inner tube in dry drilling.
- Ascent of the inner tube safer, thanks to the locking bushing.
- The same Overshot, changing an adaptor and a pin, covers N, H and P diameters.
The following pages describe the complete Overshot in its different versions, the conversion kits and spares.