초록 ▼

A mud saver valve for insertion within the drill string to retain mud in the drill pipe preventing the mud column from flowing past the valve when pumping is interrupted. The mud saver valve includes an internal check valve which permits increased flow of mud upward through the valve when a predeter

A mud saver valve for insertion within the drill string to retain mud in the drill pipe preventing the mud column from flowing past the valve when pumping is interrupted. The mud saver valve includes an internal check valve which permits increased flow of mud upward through the valve when a predetermined downhole pressure is reached. The increased flow of the check valve prevents a blow-out of the plug spear in the event sudden upward pressure is encountered. The check valve forms a part of the plug spear which is removable from the mud saver valve to facilitate the running of wireline tools.

대표청구항 ▼

In a mud saver valve for retaining fluids within a drill string, the mud saver valve including a tubular body adapted to be disposed within the drill string and an axially movable piston having a fluid passageway and disposed within the tubular body, a closure plug mounted within the upper end of th

In a mud saver valve for retaining fluids within a drill string, the mud saver valve including a tubular body adapted to be disposed within the drill string and an axially movable piston having a fluid passageway and disposed within the tubular body, a closure plug mounted within the upper end of the mud saver valve, said closure plug comprising: a removable spear body seated within the upper end of the mud saver valve, said spear body including a spear sleeve removably seated within the closure plug, a spear head telescopically receiving said spear sleeve, and check valve means; the piston biased against the downhole flow of fluids to selectively engage said closure plug closing the fluid passageway, said spear head telescopically extending relative to said spear sleeve when fluid pressure downhole of said spear body exceeds a predetermined fluid pressure thereby opening said check valve means allowing fluid exceeding said predetermined fluid pressure to flow upwardly through said closure plug when the fluid passageway is closed, said spear sleeve including an outwardly disposed annular shoulder and said spear head including an inwardly disposed annular shoulder, telescoping extension of said spear head relative said spear sleeve limited by said cooperating shoulders formed on said spear head and said spear sleeve.