Fishing Tools - What is Overshot Used For?

Overshot fishing tools are used to remove stuck or lost thin-wall tubing. They apply a radially inwardly directed grip on the tubing, necking it and eventually breaking it if not previously pulled free.

The overshot tool is preferably configured to concentrate loading in a manner parting the tubing, maintaining such grip despite the relatively large diameter reduction involved in such necking. Alternatively, the overshot tool can be designed to latch and release the tubing once it is permanently stuck.

Releasing and Circulating Overshot

The Releasing and Circulating Overshot is a common tool for fishing drill collar in a diamond core barrel, drill pipe, tubing and joint. It is equipped with a high pressure seal, so it can circulate the drilling fluid under higher pump pressure after catching the fish. It also has milling shoes on the lower part to trim the top of the fish.

The basic outside construction of the overshot includes a top sub, a bowl and a standard guide, while internal parts vary according to the catch desired. If the fish diameter is near the maximum catch size, a spiral grapple and a spiral grapple control are used; if the fish diameter is considerably below the maximum catch size, a basket grapple and a mill control packer are used.

It is a very strong and reliable tool for externally engaging, packing off or pulling a catch. It requires only right hand rotation during both engaging and releasing operations.

Stuckey's Specialty Tools’ releasing and circulating overshot is the strongest available fishing tool for engaging, packing off or pulling a catch. The internal parts of this overshot are designed to allow a user to dress the overshot for various types of catch, and to avoid damage or distortion to the catch or overshot while engaged, by providing helically tapered spirals in the inside diameter of the overshot’s bowl.

This overshot has a very simple and effective structure, and can catch a large number of fish at a high success rate. It can be dressed with either a spiral grapple, or a basket grapple, and is made from a high-quality raw material. It is forged and machined with CNC lathe, and advanced heat treatment technology keeps the teeth hardness and internal toughness of the grapple.

The overshot is equipped with a control spring to maintain the basket gripper in a substantially axially displaceable position relative to the overshot bowl. This allows the overshot to be withdrawn without having to withdraw the overshot basket from the wellbore.

The overshot is also provided with a heavy-duty non-releasable, "planted" overshot for retrieval of downhole items with damaged or missing external fish necks. This overshot is inserted into the tubing below the drilled hole and lowered over the outside wall of the downhole item. The overshot is then "planted" onto the downhole item by the operator using a standard releasable pulling tool or a Peak HD FRC pulling tool.

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Short Catch Overshot

Short catch overshot, also known as a shorty, is an external fishing tool that uses the latest in tubing technology to extract stuck pipe. It combines the power of a magnetic motor with the latest in downhole machining to produce an overshot of exceptional strength and durability. It may be outfitted with a number of proprietary and standard components including a top coupling, a bowl, a high-tech syringe and a well-matched guide.

The best way to determine which model is right for you is to consult with a Schlumberger representative Overshot. They are experts at identifying the most effective tools for your application and helping you choose the best model to meet your needs and budget. For more information, contact your local Schlumberger representative today.

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Pipe Fishing Tool

Overshot is a type of external catch device that does the opposite of taper taps, connecting to threads around the outside diameter of the pipe being retrieved. This allows the assembly to grip and recover lost pipes, drill bits, and other down-hole equipment that have slipped into the well.

Overshots can be used to retrieve down-hole tools and equipment in water wells and oil & gas production sites. They are typically screwed onto the bottom of a pipe with a diameter similar to the lost pipe and lowered into the casing, then they grip the outside diameter of the lost pipe.

The pipe is then raised up through the well and pulled out. It may need to be swung out by hand, using a long-handled grapple or another tool that can mesh up along the inside of the pipe and pull it out.

There are many types of overshots to choose from, and each one is designed with a unique purpose. Some of these include:

Junk Baskets (Poor Boy Junk Baskets) – This is a common tool for catching down-hole junk and other debris that is left over in a wellbore, generally after a contractor has removed the tubing or packer or otherwise has to remove it from the well. These tools can be made in a variety of different ways, and each individual one is custom designed by the contractor who makes them.

Magnets – These are another common tool for catching down-hole junk, but they are more commonly used by rotary drilling contractors to dislodge the stuck bit and drill joint or the other piece of down-hole hardware that has become stuck in the hole. They can be a little more expensive than other down-hole recovery tools, but they are also effective and can be easily removed from the well.

Jars – These are also common for catching down-hole junk, and they can be very powerful, enabling them to dislodge stuck bit, drill joint or other down-hole hardware that has become stuck in a hole. They can be very effective, but they are also very costly, so they are usually reserved for high-risk jobs.