Retractable core barrel valving apparatus

摘要

The drilling apparatus includes a wire line core barrel having a head assembly and a drilling tool connected to the head assembly. The head assembly includes a latch body with a landing shoulder seatable on the drill string landing ring, latches seatable in a drill string latch seat and a fluid bypass channel for bypassing from one axial side of the landing shoulder to the other, a bushing in the bypass channel, a valve member movable in the channel from an axial outer bypass channel open position and an axial inner second position extending into the bushing for one of blocking axial inward fluid flow through the bushing and restricting inward flow through the bushing. A spring is provided in the bore inwardly of the bushing for abutting against the valve member in its second position to urge the valve member axially outwardly. A latch retractor is mounted to the latch body for movement relative thereto between a latch seated position and a latch retracted position for retracting the latch body through the drill string and valving mechanism connected to the latch retractor for moving the valve member in the fluid channel to the valve member outer open position. An overshot coupling device retracts the latch retractor and thereby retracts the latches and pull the ball portion outwardly of the bushing to decrease resistance to drilling fluid flow inwardly through the bushing.