APPARATUS AND METHOD FOR INSERTING AND RETRIEVING A TOOL STRING THROUGH WELL SURFACE EQUIPMENT

摘要

Well surface equipment is provided to seal around the outer surface of portions of tool sections as the tool sections are assembled or disconnected in a portion of the well surface equipment. The portion of the well surface equipment is isolated from wellhead pressure to enhance well operator control during assembly or disassembly of a tool string. Also, if a fluid path is opened up due to activation of the tool string (such as initiation of a detonating cord that is placed in the fluid path), a barrier mechanism is actuated to block fluid communication through this fluid path so that a portion of the well surface equipment can remain isolated from wellhead pressure to enable convenient retrieval and disconnection of tool sections.