Overshots

Description
Overshot is one of the necessary equipment for wireline drilling which could be put into the hole. This fishing tool is used to connect with the inner tube assembly and lift it up. Overshot is attached to drill rod and lowered over the pipe or stuck in the borehole. Hardened and self-cutting threads inside overshot firmly grasp the pipe, allowing the fish (such as inner tube and core) to be pulled from the hole.

Features
1. The overshot is the simplest fishing tool. It is used in back-off operation where its solid body offers high strength.
2. Solid one-piece construction furnished with a fine case hardened thread is on its shallow tapered inner circumference.
3. Four or six longitudinal flutes are machined across the internal wickers permitting elimination of cuttings when the hardened threads embed in the fish.
4. The tool is normally furnished with a box up connection.
5. The rotary overshot is a non-releasable tool and should normally be run below a safety joint in order to have positive release mechanism from the fish.
6. It is economical, safe and easy to use.

Principle
CDG’S overshot is an external catch fishing tool designed to catch the inner tube and core from the hole. Once the inner tube of a wireline core barrel is full of core sample, overshot is released from the top. Wireline overshot assembly slides inside the wireline drill rods and locks the spear head of core barrel. Along with inner tube, it is pulled out with steel wire rope.

China Drilling Geological Equipment Ltd. is a professional manufacturer of drilling tools. Main products cover impregnated synthetic diamond core bits, surface-set diamond bits, PDC core and noncoring bits, rod shoes & casing shoes, reaming shells, drill rods, core barrels, fishing tools (like overshots or wireline overshot assembly), water swivels, hoisting plugs, casing cutter assembly, adapter subs, wrenches, recovery tools and foot clamps. 80% of our products are sold abroad.