Spear fishing tool

Abstract

A spear fishing tool for engaging an object to be removed from a well bore, commonly called a 'fish'. The spear fishing tool is characterized by a cylindrical housing, typically attached to a length of coiled tubing by means of a top sub and fitted with a reciprocating, hydraulically-operated plunger seated on an internal spring and having a bevelled end facing the down-hole 'fish'. Multiple latch fingers lie adjacent to the housing and are movably secured in place between the housing and plunger by means of a slotted finger collar threadably attached to the housing. The piston is further provided with a piston groove or slot that selectively matches corresponding lobes formed in the latch fingers, respectively, to facilitate the following: engagement of the tool housing with the fish; hydraulic extension of the piston downwardly with respect to the housing to effect retraction of the latch finger lobes into the piston groove or slot; extension of the tool housing through the fish neck opening; and spring-biased retraction of the piston upwardly to mismatch the finger lobes and the piston groove or slot and extend the latch finger lobes from the piston groove or slot into engagement with the internal groove of the fish.