During drilling and completion and workover operations, drill rods, drill collars, casings, tubing strings are stuck or broken, drill bit cones are dropped, logging tools or cables are stuck, cable wire ropes are broken, packers are broken Interruption of normal drilling, workover, and completion operations due to stuck, sand, serious leaks, well collapse, blowout, etc., need to use fishing tools or take special measures to remove leaks, collapse, stuck, spray to resume normal operations. The operation and process of removing leaks, collapses, jams, and sprays is called "fishing."