Patent ID: 7287596

Claim:
A well comprising: a bore hole extending from a surface location and penetrating a hydrocarbon bearing interval, a casing string in the bore hole having a predetermined minimum internal diameter, and a flapper valve assembly having: an internal diameter at least as large as the casing internal diameter and providing a tubular housing providing part of the casing siring and being at a location between the hydrocarbon bearing interval and the surface location, a flapper valve member movable between a first inoperative position allowing upward and downward flow through the casing string and a second operative position allowing upward flow and preventing downward flow through the casing string, and a manipulable device for holding the flapper valve member in the first position, the manipulable device comprises a sliding sleeve having a lower position holding the flapper valve in a stowed position and an upper position allowing the flapper valve to move to the second operative position allowing upward flow and preventing downward flow through the casing string, the sliding sleeve protecting the flapper valve from accumulating debris in the stowed position, a first end of the sleeve having a downwardly facing shoulder for receiving operative elements of a setting tool and thereby pulling the sliding sleeve upwardly into the upper position, and a second end of the sleeve adapted to sealingly engage the tubular housing when the flapper valve is disposed at the first position.