Tubing drain valve useful with heavy, sand-bearing oil

An apparatus suitable for conducting fluid through a conduit therein from a first to a second port and including means for producing a fluid passage through a wall of said apparatus to communicate said conduit with the exterior of said apparatus intermediate said ports, comprising:

• a hollow body having a first section including said first port and a second section including said second port;
• a valved fluid passage between the interior and the exterior of said hollow body through a wall of said hollow body intermediate said first and second ports;
• means for engaging a surface of an object exterior of said hollow body for temporarily preventing movement of said first section in one direction along the longitudinal axis of said hollow body, said engaging means extending outwardly from said hollow body and being at least partially retractable within said fluid passage in its opened position so that said engaging means is disengaged from said surface and movement of said apparatus is permitted after said fluid passage is in its opened position;
• and
• means for opening said valved passage in response to movement of said second section in said direction along the longitudinal axis of said hollow body while movement of said first section is prevented.

A method for opening an initially closed fluid communication passage through the sidewall of a device between the exterior of said device and a conduit suitable for conducting fluid from a first to a second end of said device, said device having first and second longitudinally movable sections, comprising the steps of:

• extending engaging means outwardly from said device for temporarily preventing movement in one direction of said first section along the longitudinal axis of said device by engaging a surface of an object exterior of said device;
• moving in said direction said second section of said device along said longitudinal axis until said passage is opened;
• and
• retracting said engaging means at least partially into said opened passage to permit movement of said device.

A method for opening an initially closed fluid communication passage through the sidewall of a sub suitable for incorporation in a pipe string in a cased well bore, comprising:

• engaging the interior wall of the casing of said well bore with a plurality of dogs extending from a sleeve disposed about a tubular body suitable for incorporation in a pipe string to temporarily prevent movement of said sleeve;
• moving said tubular body relative to said temporarily fixed sleeve a predetermined distance along the longitudinal axis of said body without opening said passage;
• opening said passage only after said tubular body has been moved said predetermined distance;
• and
• disengaging said dogs to permit movement of said sleeve and said tubular body.

A sub suitable for incorporation in a pipe string disposed in a well bore casing for conducting fluid through said sub along the longitudinal axis of said sub and including means for producing a fluid communication passageway through the side wall of said sub, comprising:

• top and bottom tubular members adapted for incorporation in a pipe string, said tubular members longitudinally movable relative to one another;
• a valved fluid passage between the interior and the exterior of the side wall of said sub, said passage openable by relative longitudinal movement of said top and bottom tubular members;
• means for engaging said casing exterior of said tubular members for temporarily preventing movement of said bottom tubular member along the longitudinal axis of said casing, said engaging means extending outwardly from said tubular members and being at least partially retractable within said fluid passage in its opened position to that movement of said sub is permitted after said fluid passage is in its opened position;
• and
• means for opening said valved fluid passage in response to movement of said top tubular member relative to said bottom tubular member.