Introduction of Fishing Tools（5）

Pipe cutting tools

1. Hydraulic cutter

Hydraulic cutter is a tool that uses water horsepower to push the cutter to cut in the tube.

1）working principle

When the cutting knife is lowered into the predetermined cutting position, the pump is circulated and the displacement is gradually increased. The drilling fluid passes through the nozzles of the upper and lower valves to cause a pressure difference between the upper and lower sliders. This pressure difference causes the lower valve to overcome the spring. The resistance moves downwards, pushing the cutter head to rotate outward into the cutting state. At this time, the rotary cutter can cut. After the fish is cut off, the pressure difference between the stop of the pump and the down valve disappears. The slide valve is reset by the upward movement of the compressed spring. The cutter head rotates inward to reset under the action of the spring pressing piece. The cutter can be removed from the well.

2）Internal structure

The hydraulic cutter shall consist of an upper joint, a body and a lower joint.

Related tools

1、Impression Block

The mark is made by inserting soft lead into the lower end surface of the alloy structural steel body for salvage operations. The structure of the impression block can be probed into the well hole to detect the shape of the top of the falling fish.

2、Safety connector

The safety joint is a special tool assembled from two pieces. It is a special tool that protects the drill string in drilling, workover, oil test and other projects.

It is suitable for downhole accident handling, as well as for halfway testing during drilling and coring. Connect it to the required part of the drill string used to protect the drill string and not affect the normal operation of the drilling tool. Once the tool is stuck in the downhole, the drill string above the card point can be pulled out by the safety joint, and it can be docked when drilling again .