Importance

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Abstract

A plug catcher assembly comprising an elongated adapter sub having threads on its upper end for connecting to the pipe string, a reverse circulation or jet sub threadedly connected to the adapter sub, and a catcher sub threadedly connected to the jet sub for catching plugs. The catcher sub and the jet sub have a plurality of upwardly and outwardly directed apertures in its wall which are arranged to promote turbulent flow and slurry mixing and to initially direct such slurry flow in the upward direction. The apertures are vertically spaced in the catcher sub so as to prevent pressure locking and to assure that the sub stays free of cement slurry. The catcher sub can contain and catch as many as eight plugs to save rig time by eliminating tripping of the string between plugging operations. Additionally, a plug launching apparatus is disclosed for use in launching a plurality of plugs during a cementing operation. Upper and lower restrictions are provided in the bore of the launching sub so that pressure indications are given as a plug passes through a restriction and is launched.

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First Claim