What are the main precautions for reverse circulating junk basket?
1. It can not be used in the formation with high hardness;
2. The inner diameter of the fishing basket shall be greater than the maximum outer diameter of the cone;
3. Downhole conditions shall be normal;
4. Run in the well to the bottom 0.2-0.3m, start the pump for circulation for half an hour, wash the bottom of the well, then stop the pump and throw the ball to realize reverse circulation;
5. Light pressure 10-30 kn, maximum not more than 50kN, slow rotation, drilling and fishing. When the footage exceeds 0.1M from the fishing basket chuck to the bottom of the milling shoe, the pump can be stopped and Pooh.
Matters related to reverse circulation nesting and salvaging:
When milling large pieces of debris in the well, use the counter circulation of the killing fluid to make the debris and falling objects enter the fishing drum. After stopping the pump, leave the large pieces of debris and falling objects in the sleeve and bring them out of the ground. It reduces the circulation displacement and avoids the risk of stuck drilling, improves the equipment utilization rate, and reduces the number of trips.
The reverse circulation sleeve milling fishing tool is composed of a sleeve milling head, a sleeve milling cylinder, a threaded joint, a flap seat tube, a flap, and a positioning post.
The fishing drum borrows the principle of the rat cage, and processes a cover plate that can be opened and closed at any time in the barrel. The top flap is opened by reverse circulating water flow, so that debris enters the upper sleeve of the flap, and the pump is turned over The plate is closed by its own weight, and fine debris has been brought out of the ground with the workover fluid, and the larger debris stays inside the casing mill tube, which is carried out of the well with the casing mill tube when it starts drilling. At the same time, the flip plate seat has a drainage hole, and the well can be washed and killed after fishing.
Reverse circulation casing milling and fishing tools are suitable for casing, grinding, milling and cleaning of fish heads in oil and water wells, especially directional wells with horizontal wells, horizontal wells, and construction wells with large well depths and large construction displacement requirements. Construction wells that are prone to debris and small objects are particularly suitable.