High temperature completion plug

1. For use in closing a cylindrical passageway through a working member in which the passageway is defined in part by a reduced diameter internal circumferential sealing surface and an internal locking groove, a completion plug, comprising:

a plug body having a cylindrical external surface receivable within the cylindrical passageway of the working member and having an annular recess in said plug body thereby forming a reduced thickness circumferential lip on which is provided an external circumferential sealing surface, the circumferential lip having inward radial compressibility and being dimensioned to radially compressibly engage the working member internal circumferential sealing surface and having on said cylindrical external surface a circumferential locking groove; and

a locking ring receivable in the working member internal locking groove and simultaneously in said plug body external circumferential locking groove for thereby locking said plug body within the working member.

2. A completion plug according to claim 1 wherein said plug body external circumferential sealing surface has thereon at least one radially extending, integral, circumferential bead.

3. A completion plug according to claim 1 including an annular recess in said plug body radially inwardly of said external circumferential sealing surface thereby forming a reduced thickness circumferential lip on which said external circumferential surface is formed thereby providing increased inward radial compressibility of said plug body sealing surface.

4. A completion plug according to claim 1 wherein said plug body includes an integral, axial central post portion by which said plug body is insertable into the cylindrical passageway of a working member.

5. For use in closing a cylindrical passageway through a working member in which the passageway is defined in part by a reduced diameter internal circumferential sealing surface and an internal locking groove, a completion plug system, comprising:

a plug body having a cylindrical external surface receivable within the cylindrical passageway of the working member and having an external circumferential sealing surface dimensioned to radially compressibly engage the working member internal circumferential sealing surface and having on said cylindrical surface an external locking groove;

a locking ring received in said plug body external locking groove; and

a completion tool of exterior dimensions greater than the cylindrical passageway in the working member and enveloping an upper portion of said plug body for retaining said locking ring in said locking groove, said plug body being axially displaceable by downward force causing said locking ring to pass from envelopment by the completion tool and to enter into the working member internal locking groove.

6. A completion plug system according to claim 5 wherein said plug body external sealing surface has thereon at least one radially extending, integral, circumferential bead.

7. A completion plug system according to claim 5 including an annular recess in said plug body radially inwardly of said external circumferential sealing surface thereby forming a reduced thickness circumferential lip on which said external circumferential surface is formed thereby providing increased inward radial compressibility of said plug body sealing surface.

8. A completion plug system according to claim 5 wherein said plug body includes an integral, axial central post portion by which said plug body is insertable into the cylindrical passageway of a working member.

9. A completion plug system according to claim 8 wherein said completion tool releasably telescopically envelops said central post.

10. A completion plug system according to claim 8 including:

a tubular insertion member telescopically and releasably positioned on said central post portion of said plug body and having means at an upper end for receiving a piston rod by which said plug body is axially positionable, said completion tool being axially and detachably positioned on said insertion tool, downward force on the insertion member servicing to downwardly displace said plug body to release said lock ring into the working member internal locking groove.

11. For use in closing a cylindrical passageway through a working member in which the passageway is defined in part by a reduced diameter internal circumferential sealing surface and an internal locking groove, a completion plug assembly, comprising:

a plug body having a cylindrical external surface receivable within the cylindrical passageway of the working member and having an external circumferential sealing surface dimensioned to radially compressibly engage the working member internal circumferential sealing surface and having on said cylindrical surface an external locking groove and having an integral, axial central post portion;

a locking ring received in said plug body external locking groove;

a tubular insertion member telescopically and releasably secured to said plug member central post portion; and

a completion tool of external diameter greater than the cylindrical passageway in the working member and enveloping and releasably secured to said insertion tool, and having a skirt portion for retaining said locking ring within said plug body exterior locking ring groove, said insertion member and thereby said completion tool being downwardly displaceable to force said plug body into the working member passageway whereby said locking ring is released to expand into said internal locking groove, said insertion member and said completion tool being thereafter extractable from said plug body.

12. A completion plug assembly according to claim 11 wherein said plug body external sealing surface has thereon at least one radially extending, integral, circumferential bead.

13. A completion plug assembly according to claim 11 including an annular recess in said plug body radially inwardly of said external circumferential sealing surface thereby forming a reduced thickness circumferential lip on which said external circumferential surface is formed thereby providing increased inward radial compressibility of said plug body sealing surface.

14. A completion plug assembly according to claim 11 wherein said insertion member has means at an upper end for receiving a piston rod by which said plug body is axially positionable within the working member passageway.