Mud saver valve

A fluid retaining apparatus, in a top drive assembly for retaining fluid in the top drive assembly when a tubular is disconnected therefrom, comprising:

• a remote controlled shut-off valve mounted within a first tubular body, wherein said first tubular body is adapted to be detachably mounted below said top drive, wherein said remote controlled shut-off valve controls fluid flow into and out of said top drive;
• said first tubular body having a top end and a bottom end;
• a second tubular body adapted to be insertably mounted in said bottom end of said first tubular body;
• said second body being a downwardly extending closure member, said closure member having a bore extending axially therethrough;
• an axially movable piston disposed within said second body, said piston having a flange extending radially outwardly therefrom into contact with said body, a passage having a cross-sectional area for the flow of fluid therethrough, said passage being substantially coaxial with said bore, and a top side;
• said closure member having an upper side, wherein said upper side further comprises a plurality of flow passages, each having a cross-sectional area, such that the sum of the cross-sectional areas of said plurality of flow passages at least substantially equals the cross-sectional area of said passage within said piston;
• said upper side further having a plurality of check valves to allow fluid to flow upwardly therethrough, wherein said flow allows downhole pressure to be detected;
• a ring member engaging the lower end of said body and extending radially inwardly into contact with a compression spring;
• and
• said compression spring disposed within said body and compressed between said flange and said ring member, wherein said compression spring urging said piston axially upward blocking said plurality of flow passages, thereby preventing the downward flow of fluid therethrough.

A valve for retaining fluid in a kelly when a tubular is disconnected therefrom, comprising:

• said kelly having an upper end and a lower end;
• a first tubular body adapted to be detachably mounted to the lower end of said kelly;
• a second tubular body adapted to be inserted into said first tubular body;
• said second body being a downwardly extending closure member, said closure member having a bore extending axially therethrough;
• an axially movable piston disposed within said second body, said piston having a flange extending radially outwardly therefrom into contact with said body, a passage having a cross-sectional area for the flow of fluid therethrough, said passage being substantially coaxial with said bore, and a top side;
• said closure member having an upper side, wherein said upper side further comprises a plurality of flow passages, each having a cross-sectional area, such that the sum of the cross-sectional areas of said plurality of flow passages at least substantially equals the cross-sectional area of said passage within said piston;
• said upper side further having a plurality of check valves to allow fluid to flow upwardly therethrough, wherein said flow allows downhole pressure to be detected;
• a ring member engaging the lower end of said body and extending radially inwardly into contact with a compression spring;
• and
• said compression spring disposed within said body and compressed between said flange and said ring member, wherein said compression spring urging said piston axially upward blocking said plurality of flow passages, thereby preventing the downward flow of fluid therethrough.

A valve for retaining fluid in a rig assembly when a tubular is disconnected therefrom, comprising:

• a tubular body being a downwardly extending closure member, said closure member having a bore extending axially therethrough;
• an axially movable piston disposed within said body, said piston having a flange extending radially outwardly therefrom into contact with said body, a passage having a cross-sectional area for the flow of fluid therethrough, said passage being substantially coaxial with said bore, and a top side;
• said closure member having an upper side, wherein said upper side further comprises a plurality of flow passages, each having a cross-sectional area, such that the sum of the cross-sectional areas of said plurality of flow passages at least substantially equals the cross-sectional area of said passage within said piston;
• said upper side further having a plurality of check valves to allow fluid to flow upwardly therethrough, wherein said flow allows downhole pressure to be detected;
• a ring member engaging the lower end of said body and extending radially inwardly into contact with a compression spring;
• and
• said compression spring disposed within said body and compressed between said flange and said ring member, wherein said compression spring urging said piston axially upward blocking said plurality of flow passages, thereby preventing the downward flow of fluid therethrough.

A valve for retaining fluid in a rig assembly when a tubular is disconnected therefrom, comprising:

• a cylinder having a first end and a second end, wherein said cylinder houses said valve;
• a piston having a fluid passageway along its entire length, and having first and second ends, said first end of said piston having a first external diameter, and said second end of said piston having a second external diameter greater than said first external diameter, and a spring having first and second ends and sized to slide over the first end of said piston, but not over the second end of said piston;
• and
• an adjustment ring having external threads selected to be threaded into the second end of said cylinder and to bear against the first end of said spring, wherein said adjustment ring is threaded into the second end of said cylinder against one end of said spring.

A method for retaining fluid, in a top drive unit, of a top drive assembly, when a tubular is disconnected therefrom, comprising:

• detachably mounting a first tubular body below said top drive;
• inserting a second tubular body into said first tubular body, wherein said second tubular body is a valve;
• disposing an axially movable piston within said second tubular body, said piston having a flange extending radially outwardly therefrom into contact with said body, a passage having a cross-sectional area for the flow of fluid therethrough, and a top side;
• providing said valve with a plurality of flow passages each having a cross-sectional area such that the sum of the cross-sectional areas of said plurality of flow passages at least substantially equals the cross-sectional area of said passage within said piston;
• providing said valve with a plurality of check valves to allow fluid to flow upwardly therethrough, wherein said flow allows downhole pressure to be detected;
• engaging a ring member in the lower end of said body, wherein said ring member extends radially inwardly into contact with said piston;
• and
• compressing a compression spring disposed within said body between said flange and said ring member;
• urging said piston axially upward, by said compression spring, so that said plurality of flow passages is blocked by said top side of said piston, thereby preventing the downward flow of fluid therethrough.