Annular chamber seal

• US 5,799,949 A
• Filed: 01/23/1997
• Issued: 09/01/1998
• Est. Priority Date: 03/24/1993
• Status: Expired due to Term

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Hickey, Kurt A., Beall, Clifford H., Rawson, Michael S.
• Primary Examiner(s): DePumpo, Daniel G.
• Application Number:
  US08/787,781
• Time in Patent Office: 586 Days
• Field of Search: 277/115, 277/117, 277/236, 277/1, 277/170, 277/171, 277/59, 277/70, 277/110, 277/144, 277/167.5, 166/319, 166/320, 166/321, 285/140, 285/141, 285/142, 285/143, 285/351, 285/334, 285/332.2, 285/333, 285/332, 285/332.1, 285/334.2
• US Class Current: 277/300
• CPC Class Codes: E21B 17/025 Side entry subs
• CPC Class Codes: E21B 17/0423 with plural threaded sections, e.g. with two-step threads
• CPC Class Codes: E21B 34/10 operated by control fluid supplied from outside the borehole
• CPC Class Codes: E21B 34/106 the retrievable element being a secondary control fluid actuated valve landed into the bore of a first inoperative control fluid actuated valve

Abstract

Internal and external metal-to-metal radially interfering seals are provided for an annular chamber. Typically, an annular chamber is used in tubular goods to be part of the hydraulic control circuitry, such as for operating subsurface equipment such as a subsurface safety valve. Resilient seals are eliminated and sealing reliability is enhanced by a design which features metal-to-metal seals internally and externally, preferably assembled by an external two-step thread. The radial interference seal, which is internally disposed, is constructed so as to be incapable of experiencing tensile loads. This reinforces joint integrity by minimizing stresses on thin components.

Claims

1. An apparatus for isolating a chamber from at least one of pressures internal to the apparatus and pressures applied externally to the apparatus, said apparatus defining a tubularly shaped wall containing a chamber, said chamber comprising a portion of a downhole fluid-actuated system, comprising:

an elongated housing comprising a threaded pin and a threaded box tubular components, said components when threaded together forming a wall, said wall having an interior and exterior face and defining an annular chamber therein and at least one passage running in said wall in communication with said chamber and serving as part of a pressurized fluid-actuated downhole control system;

at least one internal seal to prevent at least one of flow into said chamber from pressure against said internal face and pressure in said chamber from escaping past said interior face;

at least one external seal to prevent at least one of flow into said chamber from pressure against said external face and pressure in said chamber from escaping past said exterior face;

said chamber disposed in said housing in communication with said seals; and

said internal and external seals formed by metal-to-metal contact between said housing components, whereupon threading of said housing components, fluid pressure can be communicated through said chamber and said passage for operation of a fluid-actuated control system.

2. The apparatus of claim 1, wherein:

said internal seal is formed by a radial interference fit between said housing components; and

said chamber extending annularly within said wall.

3. The apparatus of claim 2, wherein said internal seal comprises a plurality of radial interference seals.

4. A sealing system against internal and external pressures applied to an annular chamber in a downhole tubular forming a part of a fluid-actuated system, comprising:

an elongated housing having a bore therethrough and forming an annular chamber formed in a wall thereof, said wall having an internal face exposed to said bore and an external face forming the outside of the downhole tool, said wall further forming at least one passage therethrough, independent of said bore and in communication with said chamber as a part of a pressurized fluid control system through said wall;

said housing composed of a threaded pin and a threaded box members, said chamber formed between said pin and box members when threaded together;

at least one internal seal exposed to said bore and said chamber, comprising of a metallic component of said pin engaging a metallic component of said box;

at least one external seal exposed to said chamber and said external face formed by metallic component contact between said pin and said box;

said internal seal disposed on an opposite side of said chamber from said external seal.

5. The sealing system of claim 4, wherein said internal seal comprises a radial interference fit.

6. A method of sealing a chamber in a wall of a downhole tubular against internal and external applied pressures, comprising:

forming a threaded tubular pin and a threaded tubular box member so that when threaded together, a chamber is formed in a wall defined by said threaded together pin and box members;

providing an internal metal-to-metal seal for said chamber, between said pin and box;

threading said pin and box to form said internal seal;

providing an external metal-to-metal seal due to said connection;

disposing said internal seal on the opposite side of said chamber from said external seal;

providing at least one passage in said wall in fluid communication with said chamber;

connecting said passage in a fluid control system independent of an internal bore formed by said wall.

7. The method of claim 6, further comprising:

providing at least an interference fit for said internal metal-to-metal seal.

8. The method of claim 7, further comprising:

minimizing the potential of longitudinal stresses on the thinner wall pin end adjacent said internal seal.

9. A sealing system for an annular passage in a downhole tool, comprising:

an elongated housing having a bore therethrough and forming an annular chamber;

said housing composed of threaded pin and box members;

at least one internal seal exposed to said bore and said chamber, comprising of a metallic component of said pin engaging a metallic component of said box;

said internal seal comprises a radial interference fit;

said metallic components comprising said internal seal are unrestrained longitudinally to minimize stresses due to applied forces in a direction parallel to said bore;

at least one external seal exposed to said chamber and to outside the downhole tool which is on the opposite side of said threaded pin and box members than said bore, said external seal formed by metallic component contact between said pin and said box;

said threaded pin and box members further comprising at least one passage therethrough in fluid communication with said chamber to allow said chamber to function in a pressurized fluid control system, independent of said bore.

10. An apparatus for downhole use, comprising:

a pin member and a box member joinable by mating threads to form an internal bore and an annular chamber therebetween;

at least one seal to prevent pressure in said bore or from outside said threaded pin and box from entering said chamber;

said pin and box members, when threaded together, defining an internal wall which defines at least a portion of said internal bore and said chamber, said internal wall formed being thin to facilitate radial penetration from said bore into said chamber;

said chamber in flow communication through one of said threaded pin and box member with at least one passage in a pressurized fluid control system, said passage being distinct from said internal bore, for normal operation of said pressurized fluid control system;

whereupon said thin wall selectively facilitates an additional entry into said chamber for alternative operation of the fluid control system.

11. The apparatus of claim 10, wherein said seal to keep internal bore fluids out of said chamber is formed in part by said thin wall.

12. The apparatus of claim 11, wherein said thin wall is part of a metallic interference fit between said pin and said box to form said seal.

13. The apparatus of claim 12, wherein said thin wall is of a sufficient thickness to withstand said interference fit and applied internal pressures in said chamber.

14. The apparatus of claim 13, wherein:

said pin and box joined by an internal and external seal with said chamber therebetween;

said seal comprises a metal interference fit internally and externally to isolate fluid internal and external of said joined pin and box from entry into said chamber.

15. The apparatus of claim 14, wherein said internal seal is longitudinally displaced from said external seal with said chamber in between to allow said thin wall to form part of said chamber.

16. The apparatus of claim 10, wherein:

said pin and box are joinable by longitudinally displaced internal and external seals;

said chamber is disposed therebetween to allow said thin wall to form a part of said chamber.

17. A method of providing access to a fluid control circuit through a tubular, comprising:

fabricating a threaded pin and a threaded box;

threading said pin to said box;

creating an annular chamber by said threading;

creating an internal bore by said threading;

creating at least one seal for said chamber by said threading;

providing a thin wall to separate said internal bore from said chamber.