Tree test plug

Abstract

A test plug for sealing a bore within a tubing hanger comprising an annular plug body having an axial bore extending therethrough, the axial bore forming a tapered annular seat and an enlarged receptacle within the plug body; a plurality of support dogs retractably mounted within corresponding slots formed in the plug body adjacent a lower portion of the receptacle; a mandrel slidably received within the receptacle, the mandrel having a downwardly and outwardly facing cam surface formed on a lower portion thereof; and a stinger having a tapered closure member adapted to be received in the annular seat, a spring for biasing the closure member against the seat and a seal ring for providing a fluid-tight seal between the closure member and the seat; wherein each support dog comprises an inner beveled edge formed on an upper portion thereof which preferably matches the cam surface of the mandrel, such that when the mandrel is set the cam surface will engage the beveled edge and urge the support dogs into an annular recess formed in the tubing hanger to thereby secure the test plug within the tubing hanger; and wherein the mandrel comprises an inwardly extending annular collar and the stinger comprises an outwardly extending ring forming a downwardly facing annular shoulder which overlaps the collar above the closure member, such that the closure member will not seal against the annular seat unless the mandrel is fully set, and the mandrel will release the closure member from the annular seat during retrieval of the test plug to thereby equalize the pressure above and below the test plug.