Oil field tubular and an internal sleeve for use therewith, and a method of deactivating a float valve within the oil field tubular

A drill string float valve assembly for use with a drill string having a drilling bit at an end, the drill string float valve assembly comprising:

• at least one tubular sub having an internal passage formed between two opposing ends, each end configured for connection to an end of an adjacent drill string element;
• a flapper located within the at least one tubular sub, the flapper hinged to move between a closed position closing the internal passage and preventing flow moving up the drill string float valve assembly and past the flapper, and an open position;
• a sliding sleeve, configured to fit within the internal passage, movable from a first position where the flapper can operate freely to a second position where the sliding sleeve holds the flapper in the open position and allows free movement of tools in both directions through the drill string float valve assembly;
• and
• a retaining device, configured to prevent a deactivation tool from passing through the sliding sleeve unless the sliding sleeve is in the second position.