Collar lock and seal assembly for well tools

Abstract

A collar lock and seal assembly for releasably locking a well tool such as a pump in a well flow conductor, such as casing or tubing, and sealing with the flow conductor around the assembly to restrict flow to a path into the pump. The assembly has an annular support surface engageable with a no-go shoulder in the flow conductor, radially movable locking keys for expansion into a locking recess in the flow conductor above the no-go shoulder, a longitudinally operable bypass valve, and interference fit annular seals. First shear pins hold the assembly unlocked while running in and second shear pins are activated to lock the assembly at operating position. The seals and connected parts are coupled to resist rotation by the pump when locked in a well casing. In operation the assembly is coupled in a tool train including an electric well pump, valves, and related structure. The tool train is lowered on a cable in a well casing until the flow conductor no-go shoulder is engaged. The bypass valve allows lowering in a closed liquid filled system. Upon engagement with the no-go shoulder the keys are locked outwardly, the bypass valve is closed, and the seals form a pressure barrier around the assembly to limit flow into the pump and resist rotation of the assembly by the pump. The collar lock dog and seal assembly is unlocked for removal by a longitudinal upward force applied to the cable.