US 5,343,946 A · High pressure packer for a drop-in check valve

Abstract

A packer assembly for a drop-in check valve includes a series of stacked rings in the annulus between the housing of the drop-in check valve assembly and the surface of the bore of the landing sub. The rings include at least two elastomer rings of different hardness. The top elastomer ring is capped off by a multi-part metal ring assembly comprising oppositely facing inner and outer L-shaped rings and a central T-shaped ring. The inner and outer rings have their vertical legs vertically located against the respective adjoining annulus walls and their horizontal legs in line. The trunk of the T-shaped ring is in the gap between the horizontal legs and in contact therewith so that when the elastomer ring radially expands, the metal of the metal rings is maintained in metal-to-metal contact across the annulus. This seals the annulus and prevents extrusion by eliminating all gaps. The lower elastomer ring can likewise be capped by a similar three-part metal ring assembly. An additional horizontal surface ring is located below the multi-part ring to even the upward pressure. A coil spring or an expansion band can also be used as an anti-extrusion ring with respect to the bottom surface of the lower elastomer ring.

Claims23

Dependent claims

A drop-in check valve assembly for sealing off a drill string for controlling downhole high pressures, comprising

a landing sub with a central bore included as a joint in the drill string, said landing sub including a lower shoulder and an upward locking shoulder,
a check valve subassembly having a body with a central bore, said check valve subassembly being constrained against downward movement by the lower shoulder of said landing sub and against upward movement by said upward locking shoulder of said landing sub, said check valve further including
a ball valve housing with a ball seat at its lower end,
a ball for seating with said ball seat when the downhole pressure is in excess of the uphole pressure, and
a ball cage surrounding the lower end of said housing and telescoping therewith,
a compressible packer assembly located about said ball valve housing, the upper surface being in contact with the lower end of said check valve subassembly body and the lower surface being in contact with the upper end of said ball cage, said compressible packer assembly including
a soft elastomer ring,
an adjacent hard elastomer ring above said soft elastomer ring,
an upper multi-part anti-extrusion ring located above said hard elastomer ring for deflecting laterally by the movement of said hard elastomer ring when the downhole pressure exceeds the uphole pressure to seal off the gaps in the annulus between said ball valve housing and bore surface of said landing sub to prevent elastomer extrusion resulting from high downhole pressures, and
an expansible lower anti-extrusion metal ring to minimize elastomer extrusion at the lower end of said packer assembly.

7 more elements

A drop-in check valve assembly for sealing off a drill string for controlling downhole high pressures, comprising

a landing sub with a central bore included as a joint in the drill string, said landing sub including a lower shoulder and an upward locking shoulder,
a check valve subassembly having a body with a central bore, said check valve subassembly being constrained against downward movement by the lower shoulder of said landing sub and against upward movement by said upward locking shoulder of said landing sub, said check valve subassembly further including
a ball valve housing with a ball seat at its lower end,
a ball for seating with said ball seat when the downhole pressure is in excess of the uphole pressure, and
a ball cage surrounding the lower end of said housing and telescoping therewith,
a compressible packer assembly located about said ball valve housing, the upper surface being in contact with the lower end of said check valve subassembly body and the lower surface being in contact with the upper end of said ball cage, said compressible packer assembly including
a soft elastomer central ring portion,
hard elastomer upper and lower ring portions,
a laterally expansible upper metal ring for constraining said hard elastomer upper portion against pressure extrusion, and
a laterally expansible lower metal ring for constraining said hard elastomer lower ring portion against pressure extrusion,
said ball cage moving upward with downhole pressure in excess of uphole pressure to compress said upper and lower metal rings toward each other to cause concurrent lateral deflection expansion of said metal rings for pressure sealing the gaps in the annulus between said ball valve housing and said landing sub to prevent extrusion of said soft and hard elastomer rings as a result of high pressure and high temperature.

8 more elements

A drop-in check valve assembly for sealing off a drill string for controlling downhole high pressures, comprising

a landing sub with a central bore included as a joint in the drill string, said landing sub including a lower shoulder for constraining downward movement of a check valve subassembly and an upward locking shoulder for securing the landed check valve subassembly against upward movement,
a check valve subassembly having a central bore therethrough, including
an annular body having an external landing shelf for mating with said lower shoulder of said landing sub,
a slip with spring-loaded, outwardly biased slip fingers around the upper portion of said body for locking with said locking shoulder of said landing sub,
a ball seat assembly located in the lower end of said body,
a spring-loaded ball for seating with said ball seat assembly when the downhole pressure exceeds the uphole pressure in the central bore of said check valve subassembly,
a ball cage located below said ball for holding said ball and having flow-through side ports for allowing fluid circulation therethrough when said ball is not seated,
a compressible packer assembly located about said ball seat assembly, the upper surface being in contact with the lower end of said body and the lower surface being in contact with the upper end of said ball cage, said compressible packer assembly including
a soft elastomer central ring portion,
hard elastomer upper and lower ring portions,
a lateral expansible upper metal ring for constraining said hard elastomer upper ring portion against pressure extrusion, and
a lateral expansible lower metal ring for constraining said hard elastomer lower ring portion against pressure extrusion,
said body including an upward-facing holding surface and said slip fingers including downward-facing constraining surfaces,
said body being moved upwardly by said ball with a downhole pressure in excess of an uphole pressure, to thereby move said upward-facing holding surface of said body into contact with the downward-facing constraining surface of said slip fingers so that said body is prevented from further upward movement,
said ball cage moving upward with downhole pressure in excess of uphole pressure to compress said upper and lower metal rings toward each other to cause concurrent lateral deflection expansion of said metal rings for sealing the gaps in the annulus between said ball valve housing and said landing sub to prevent extrusion of said soft and hard elastomer rings as a result of high pressure and high temperature.

12 more elements

Dependencies are inferred from the claim text.

High pressure packer for a drop-in check valve

Life of this patent

High pressure packer for a drop-in check valve

Life of this patent

Abstract

Claims23