Reverse circulation junk basket is the use of drilling fluid flow near the bottom at the local counter-cyclical revenue will be underground debris within the basket of a fishing tool. Reverse circulation junk basket is a versatile magnetic modular fishing tool. It on the rim that is junk basket; the basket into the anti-loop magnetic core is a fishing basket; the mill shoe can be formed into the first reverse circulation claw a claw.
Combination of reverse circulation junk basket mainly by the connector, cylinder, ball, bell and for the basket, core, milling shoes, claws top form.
Reverse circulation junk basket structure shown in Figure 13-12A. Magnetic structure of reverse circulation junk basket shown in Figure 13-12B. Working principle of reverse circulation junk basket shown in Figure 13-12C.
1, grinding shoes outside diameter than the diameter of well casing or at least limit the small 6.35 mm (1 / 4 inches), oriented eye wear shoes collar diameter than the rod drop into the eye at least a small fish and water 12.7 ~ 19.5 mm (1 / 2 to 3 / 4 inches) its length is 50.8 to 152 mm (2-6 inches). Casing shoes are not allowed to go out with the grinding blade.
2, if the roller pan into the fire, especially the three-cone pan into the fire. Bottom is usually tapered slim hole. Shoes should be preceded with the next drill grinding through the top well to expand your eyes fish.
3, with flat, concave bottom, conical grinding shoes Milling, draw the eye began to be repeated several times, with a small drill press mill into 30 minutes, and then gradually by 0.193 ~ 0.289 kN / mm (0.5 ~ O.751 tons / inch) into the grinding pressure. Displacement with half the normal drilling. Speed is generally 40 to 60 rev / min.
4, each 0.2 to 0.3 m into the ground or milled to mention a half-hour program on the eyes after 1 to 2 times. Plans to open eyes in the end put on the pump 3 to 5 meters, stop the pump 1 to 2 minutes and slowly grinding down to contact with broken shoes, the first iron mill into the rotation to open the pump. But not allowed to dry grinding.
Severe limp when milling should jump on mentioning draw the eye to change the parameters until smooth so far.
5, from drilling wells washed before the application of large displacement week and drilling activities.
(6) lock operation. When fishing or drilling is required after turning off the Flip the fish sticking to quit fishing tool, must be upside down to lock. Lock the front. First lift the anchor. And then gradually increase the displacement cycle, the device upside down cycle of 3 to 3.5 MPa pressure drop. Displacement of 100 to 150 L / min. Fluid will push the piston up, compressing the spring into the locked state. Locked, and the penalty is no longer played the role change. Stop the cycle upside down device to restore its original state.