초록 ▼

A metal to metal seal for downhole tools. A sealing device includes a metal seal. A nonmetal seal may be used to bias the metal seal in a radial direction in response to a pressure differential applied to the sealing device. A well tool includes a housing assembly, a closure member and the sealing d

A metal to metal seal for downhole tools. A sealing device includes a metal seal. A nonmetal seal may be used to bias the metal seal in a radial direction in response to a pressure differential applied to the sealing device. A well tool includes a housing assembly, a closure member and the sealing device. Both of the metal and nonmetal seals contact a selected one of the housing assembly and closure member when the closure member blocks flow through the housing assembly. A method of sealing between the housing assembly and closure member includes the step of displacing the closure member to relieve the pressure differential, the metal seal continuing to seal against the pressure differential until the nonmetal seal no longer seals between the housing assembly and the closure member.

대표청구항 ▼

1. A well tool, comprising: a housing assembly;a tubular closure member which selectively permits and prevents fluid flow through at least one opening in a wall of the housing assembly; anda sealing device which seals between the housing assembly and the tubular closure member, the sealing device in

1. A well tool, comprising: a housing assembly;a tubular closure member which selectively permits and prevents fluid flow through at least one opening in a wall of the housing assembly; anda sealing device which seals between the housing assembly and the tubular closure member, the sealing device including at least a first metal seal and at least one nonmetal seal, a sealing surface of the first metal seal contacting a selected one of the housing assembly and the closure member when the tubular closure member prevents flow through the opening, wherein the nonmetal seal radially biases the first metal seal into sealing contact against the selected one of the housing assembly and the tubular closure member in response to a first pressure differential across the sealing device, and wherein the sealing device further includes a second metal seal, and wherein the nonmetal seal radially biases the second metal seal into sealing contact against the selected one of the housing assembly and the tubular closure member in response to a second pressure differential across the sealing device, the first and second pressure differentials being oppositely directed relative to each other. 2. The well tool of claim 1, wherein the first metal seal includes an arm which elastically deforms, thereby biasing the first metal seal against the selected one of the housing assembly and the tubular closure member, when the closure member prevents flow through the opening. 3. The well tool of claim 1, wherein the nonmetal seal is positioned between the first and second metal seals when the sealing device is positioned between the housing assembly and the tubular closure member. 4. A sealing device, comprising: a first metal seal; anda first nonmetal seal which biases the first metal seal in response to a first pressure differential applied to the sealing device in a first direction, thereby providing a radial seal between a housing assembly and a tubular closure member, wherein fluid flow through at least one opening in a wall of the housing assembly is selectively permitted and prevented in response to longitudinal displacement of the tubular closure member relative to the housing assembly, wherein the first metal seal and a second metal seal are positioned between the first nonmetal seal and a second nonmetal seal when the sealing device is positioned between the housing assembly and the tubular closure member, and wherein the first and second metal seals and the first and second nonmetal seals are positioned on a same longitudinal side of the opening when fluid flow through the opening is prevented by the tubular closure member. 5. The sealing device of claim 4, wherein the second metal seal includes an arm which elastically deforms to bias a sealing surface of the second metal seal against a selected one of the housing assembly and the tubular closure member. 6. The sealing device of claim 4, wherein the second nonmetal seal biases the second metal seal in response to a second pressure differential applied to the sealing device in a second direction opposite to the first direction. 7. The sealing device of claim 4, wherein the first metal seal includes an arm which elastically deforms to bias a sealing surface of the first metal seal against a selected one of the housing assembly and the tubular closure member. 8. A method of sealing between a housing assembly and a tubular closure member, the method comprising: providing a sealing device including first and second metal seals and first and second nonmetal seals;applying a first pressure differential in a first direction across the sealing device while the sealing device seals between the housing assembly and the tubular closure member, wherein the tubular closure member selectively permits and prevents fluid flow through at least one opening in a wall of the housing assembly; andlongitudinally displacing the tubular closure member relative to the housing assembly to relieve the first pressure differential, the first metal seal continuing to seal against a selected one of the housing assembly and the tubular closure member until the first nonmetal seal no longer seals against the selected one of the housing assembly and the tubular closure member, wherein the displacing further comprises the first pressure differential being relieved across the first nonmetal seal, then the first metal seal, then the second metal seal, and then the second nonmetal seal. 9. The method of claim 8, wherein the applying further comprises the first nonmetal seal biasing the first metal seal in a radial direction to seal against the selected one of the housing assembly and the tubular closure member. 10. The method of claim 9, further comprising applying a second pressure differential across the sealing device in a second direction opposite to the first direction while the sealing device seals between the housing assembly and the tubular closure member. 11. The method of claim 10, wherein the second pressure differential applying further comprises the second nonmetal seal biasing the second metal seal in the radial direction to seal against the selected one of the housing assembly and the tubular closure member. 12. The method of claim 10, further comprising sealing between the tubular closure member and the housing assembly by elastically deforming an arm of the second metal seal, thereby biasing a sealing surface of the second metal seal against the selected one of the tubular closure member and the housing assembly. 13. The method of claim 12, wherein the second pressure differential applying further comprises the second nonmetal seal applying a force to the arm in response to the second pressure differential, thereby further biasing the sealing surface of the second metal seal against the selected one of the tubular closure member and the housing assembly. 14. The method of claim 8, further comprising sealing between the tubular closure member and the housing assembly by elastically deforming an arm of the first metal seal, thereby biasing a sealing surface of the first metal seal against the selected one of the tubular closure member and the housing assembly. 15. The method of claim 14, wherein the applying further comprises the first nonmetal seal applying a force to the arm in response to the first pressure differential, thereby further biasing the sealing surface of the first metal seal against the selected one of the tubular closure member and the housing assembly. 16. A method of sealing between a housing assembly and a tubular closure member, the method comprising: providing a sealing device including first and second metal seals and at least one nonmetal seal, wherein the nonmetal seal biases the first metal seal in a radial direction to seal against a selected one of the housing assembly and the tubular closure member;applying a first pressure differential in a first direction across the sealing device while the sealing device seals between the housing assembly and the tubular closure member, wherein the tubular closure member selectively permits and prevents fluid flow through at least one opening in a wall of the housing assembly;longitudinally displacing the tubular closure member relative to the housing assembly to relieve the first pressure differential, the first metal seal continuing to seal against the selected one of the housing assembly and the tubular closure member until the nonmetal seal no longer seals against the selected one of the housing assembly and the tubular closure member; andapplying a second pressure differential across the sealing device in a second direction opposite to the first direction while the sealing device seals between the housing assembly and the tubular closure member, wherein the nonmetal seal biases the second metal seal in the radial direction to seal against the selected one of the housing assembly and the tubular closure member. 17. The method of claim 16, wherein the displacing further comprises the first pressure differential being relieved across the first metal seal, then the nonmetal seal, and then the second metal seal. 18. The method of claim 16, further comprising sealing between the tubular closure member and the housing assembly by elastically deforming an arm of the first metal seal, thereby biasing a sealing surface of the first metal seal against the selected one of the tubular closure member and the housing assembly. 19. The method of claim 18, wherein the first pressure differential applying further comprises the nonmetal seal applying a force to the arm in response to the first pressure differential, thereby further biasing the sealing surface of the first metal seal against the selected one of the tubular closure member and the housing assembly. 20. The method of claim 16, further comprising sealing between the tubular closure member and the housing assembly by elastically deforming an arm of the second metal seal, thereby biasing a sealing surface of the second metal seal against the selected one of the tubular closure member and the housing assembly. 21. The method of claim 20, wherein the second pressure differential applying further comprises the nonmetal seal applying a force to the arm in response to the second pressure differential, thereby further biasing the sealing surface of the second metal seal against the selected one of the tubular closure member and the housing assembly.