FIELD

This disclosure relates to a metallic seal using geometric sealing features that are stacked above a cross-sectional symmetry line and reversible to enable sealing on tubular shapes having a wide range diametrical and surface variation and in harsh environments with extreme temperatures and pressures.

BACKGROUND

Wellhead drilling and completions equipment is used to produce petroleum-based fluids and gasses in environments that often pose harsh environments on the equipment. These systems utilize high pressure containing housings along with long lengths of pipe known as casing or tubing that is extended deep into the ground and require seals for containing and isolating areas with pressure. The depths and nature of these wells can generate extreme temperatures up to 1 ,000°F and high pressures that are in some cases beyond 20,000-psi.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, IB, 2 A, and 2B are cross-sectional and enlarged views of an embodiment of an H- shaped metallic seal resting in a seal gland right-side up and right-side down according to the teachings of the present disclosure;

FIG. 3 is a perspective view of an embodiment of an H-shaped annular metallic seal according to the teachings of the present disclosure; and

FIG. 4A, 4B, 5 A, and 5B are cross-sectional and enlarged views of an embodiment of an I- shaped metallic seal resting in a seal gland right-side up and right-side down according to the teachings of the present disclosure.

DETAILED DESCRIPTION

Metal seals are often used to contain and control pressures in the oil and gas well fracking applications - especially in the most extreme environments or applications. These seal types are ideal because metallic materials, in comparison to other alternatives such as rubber, are more inert and stable to environmental conditions, notably temperatures, pressures and chemicals. However, the typical metallic sealing elements used to create pressure boundaries are relatively inelastic and not resilient relative to non-metallic materials. Consequently, the sealing performance of metal seals can be compromised when mating against surfaces that are highly irregular (i.e. rough) or have diametrical variation because of loosely controlled manufacturing techniques or processes used to make the pipe or tubular housings.

The design of the novel metallic seal 10 provides a means for using a single piece seal solution that has the capability to seal between tubular bodies 12 and 13 having a high degree of diametrical variation up to, for example, 1/2-inch. Referring to FIGS. 1A and IB, the metal seal 10 provides a circumferential sealing profile that may include angled, straight, and tapered surfaces, as well as rings of different radiuses on the inner and outer portions of the metal seal. FIG. 3 is a perspective view of an exemplary metallic annular seal having an H-shaped cross-section shown in FIGS. 1A-2B and described above.

The metal seal 10 shown in FIGS. 1A-2B and 3 has a generally H-shaped configuration, with a first U-shaped portion 14 joined with a second inverted U-shaped portion 16. As shown, the U-shaped portion 14 of the seal 10 has two extended arms 18 and 19 that each furnish inside and outside sealing surfaces. The inside and outside sealing surfaces may include a profile and contour that are specially adapted to the intended mating bodies, including for example protruding rings and grooves. Similarly, the inverted U-shaped portion 16 of the seal 10 also includes two extended arms 20 and 21 that also furnish inside and outside sealing surfaces. The inside and outside sealing surfaces may also include a profile and contour that are specially adapted to the mating bodies, including for example protruding rings and grooves.

In a preferred embodiment, the arm extensions of one U-shaped portion 14 are thicker than the arm extensions of the other U-shaped portion 16. Further, the profile of the “crotch” area of the U- shaped portions 14 and 16 may have different contours that are configured to adapt to the intended mating bodies of the seal. Alternatively, the two U-shaped portions 14 and 16 of a seal 10 may be mirrored images of one another along the x-axis so that the seal is symmetrical along the x-axis. Further, the metallic seal may be symmetrical or mirror images along the y-axis.

The metal seal 10 is intended to be placed in a seal gland or pocket that may include a support ring 30 to mechanically energize the seal. An operator may install the seal to determine if it can be fully lowered into the gland, meaning that the inner portion of the “U” shaped profile clears or comes into light interference with the sealing diameter of the pipe. If the seal does not fit properly into the gland, the operator can then flip the reversible seal so that the other U-portion having a different inner sealing profile can be used to interface against the mating body geometry.

The seal design is also configured to be taller in cross-sectional height than the inner mating surface so that the lower seal arm will energize against a tubular or housing to create a pressure boundary, and the seal arms above the inverted U-portion will not contact or interfere with the mating bodies. Alternatively, a relief cut or groove may be cut into the mating area to allow clearance for the unused portion of the seal, either on the inner or outer mating portion of the seal. During seal makeup effort is made to install the seal ring into a gland or pocket and if there is an interference that will prevent the seal from being fully lowered into the pocket, meaning that the mating body or pipe is too large in diameter relative to the seal diameter, then the seal will be flipped so that the arm improperly interfering with the pipe, clears the height of the pipe and is not used for the sealing application. Instead the seal arm on the lower inner portion of seal will be used.

FIGS. 4A, 4B, 5 A, and 5B are cross-sectional and enlarged views of an embodiment of a generally I-shaped metallic seal 40 disposed between tubular bodies 32 and 33 having a high degree of diametrical variation up to, for example, 1/2-inch. The metal seal 40 provides inner and outer circumferential sealing profiles that may include angled, straight, and tapered surfaces, as well as rings of different radiuses on the inner and outer portions of the metal seal. The metal seal 40 shown in FIGS. 3A-4B has a generally I-shaped configuration, with a first I-shaped portion 44 joined with a second inverted I-shaped portion 46. As shown, the I-shaped portions 44 and 46 of the seal 40 each has inside and outside circumferential sealing surfaces. The inside and outside sealing surfaces may include a profile and contour that are specially adapted to the intended mating bodies, including for example protruding rings, grooves, tapers, etc.

In a preferred embodiment, the I-shaped portion 14 has a thicker dimension than the other I- shaped portion 16, or vice versa. Further, the profile of the inside and outside sealing profiles may be identical, similar but with different dimensions, or entirely different altogether. Specific areas of the I- shaped portions 44 and 46 may have different contours that are configured to adapt to the intended mating bodies of the seal. Alternatively, the two I-shaped portions 44 and 46 of a seal 40 may be mirrored images of one another so that the seal is symmetrical along a center line.

The metal seal 40 is intended to be placed in a seal gland or pocket formed between two tubular mating bodies 32 and 33. An operator may install the seal 40 in an orientation that provides the appropriate or desired sealing profile to interface with the mating body geometry.

Accordingly, the metallic annular seal described herein has an outer diameter and an inner diameter that are configured with a series of flats, tapers and radiuses to form a sealing profile. The seal has an H or I-shaped cross-sections that may be symmetrical (mirrored) (in dimension and/or contour) along a center line or they may be asymmetrical (in dimension and/or contour) along the same line. The shape and dimension of the two portions of the seal are designed to be reversible meaning that each portion may be made to fit within the envelope of the same sealing gland either right-side up or upside down.

The present disclosure relates to metallic seals primarily for use in petrochemical applications that require containment or control of pressurized fluids and gasses in environmental conditions that include extreme temperatures and chemically harsh environments. Example use cases include metallic seals within a wellhead or tubing head to seal off pressure from above and/or below a tubular body (as a hanger) that is used to hold pipe that is suspended into a well. Other applications include sealing off annular pressure between the outer diameter of a casing pipe and the inner diameter of a containment body such as a casing head or casing spools. However, often the hardness and in-elasticity of the metallic materials used to comprise the seal limit the sealing performance on parts that include high diametrical dimensional variation or considerable surface irregularities. Therefore, multiple seals with varying seal diameters are often supplied for a sealing application where operators fit a seal that best fits the sealing interface profiles. Alternatively, multiple bodies such as shims or adjustment plates can be supplied with the seal to help align it and match the application specific to the as-built sealing diameters. However, these systems add cost through the manufacturing of multiple bodies that may or may not be used in the field application. Cost is also added from added operational time during the installation, in addition to risk of failure from error in adjusting or using an incorrect seal given the as- built equipment and condition. The features of the present invention which are believed to be novel are set forth below with particularity in the appended claims. However, modifications, variations, and changes to the exemplary embodiments of the metallic seal described above will be apparent to those skilled in the art, and the metallic seal described herein thus encompasses such modifications, variations, and changes and are not limited to the specific embodiments described herein.