Metal C-Ring Seal for Stinger Axial Sealing
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Solution Overview
Problem
Conventional metal lip seals in oilfield tubulars are not suitable for thin cross-sections required in reduced bore annulus stingers due to insufficient flexibility and high cost of replacement, and existing solutions compromise annulus flow area or reliability.
Innovation Solution
The use of a metal c-ring seal with a thin cross-section, supported by a U or V shaped seat, which allows for a more resilient and flexible seal that can handle higher pressures and manufacturing tolerances, enabling reliable sealing in thin stinger sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional metal lip seals are used in reduced bore annulus stingers, then sealing function is provided, but the stinger wall cross-section cannot be sufficiently reduced and replacement cost is high
Solution Approach 1:
The patent changes the geometric parameters of the seal by using a C-ring cross-section instead of a conventional lip seal design. This allows the seal to achieve sufficient flexibility and sealing performance with a reduced cross-section thickness of 1-5mm, enabling thinner stinger walls while maintaining sealing reliability under production bore pressures.
Solution Approach 2:
The C-ring seal is designed as a thin-walled flexible component with wall thickness of 1-5mm that can deform to accommodate manufacturing tolerances and provide reliable sealing. The flexible thin-walled structure allows the seal to conform to the sealing surfaces while maintaining structural integrity under pressure, solving the contradiction between thin cross-section and sealing reliability.
2Area of stationary object
If stinger wall cross-section is reduced to increase annulus flow area, then flow area is improved, but sealing reliability deteriorates with conventional seals
Solution Approach 1:
By changing the seal geometry to a C-ring configuration with optimized wall thickness of 1-5mm, the patent enables reduced stinger wall cross-section while maintaining sealing performance. This parameter change allows the annulus flow area to be increased without sacrificing sealing reliability, as the C-ring seal provides sufficient flexibility and pressure resistance in the thinner wall section.
3Volume of moving object
If metal c-ring seal with thin cross-section is used, then stinger wall cross-section is reduced, but the seal becomes stiff and tolerance sensitivity increases
Solution Approach 1:
The patent employs a composite design combining a thin-walled C-ring seal (1-5mm wall thickness) with a V or U-shaped support seat. The thin-walled C-ring provides flexibility and tolerance accommodation, while the V or U-shaped seat provides structural support and pressure distribution. This composite structure allows the use of thinner seal cross-sections without increasing tolerance sensitivity, as the support seat compensates for the reduced structural rigidity.
Solution Approach 2:
The V or U-shaped support seat acts as an intermediary element between the thin-walled C-ring seal and the stinger body. It provides mechanical support and pressure distribution to the thin seal, enabling the seal to handle higher pressures and be less sensitive to manufacturing tolerances despite its reduced cross-section thickness.
4Strength
If c-ring seal body is designed to resist normal pressures, then pressure resistance is improved, but the seal becomes extremely stiff and reliable sealing is lost
Solution Approach 1:
The patent optimizes the wall thickness parameter of the C-ring seal to 1-5mm, which provides sufficient flexibility for reliable sealing while maintaining adequate pressure resistance through the optimized C-ring geometry and the supporting V or U-shaped seat structure.
Solution Approach 2:
The combination of thin-walled C-ring seal material with the V or U-shaped support seat creates a composite sealing system where the thin seal provides flexibility and the support seat provides structural strength, achieving both pressure resistance and sealing reliability simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The metal c-ring seal provides a reliable and reusable sealing solution with improved pressure rating and reduced tolerance sensitivity, allowing for a thinner section stinger design that maintains sealing performance under high pressures.
Implementation Method 1
the opening of the metal c-ring seal is facing the high pressure side of the production bore, which pressure tend to expand the c-profile to firm engagement with contacting surfaces
Data Source
AI summary
An oilfield tubular, such as a stinger (1), designed to be installed in a tubing hanger (2) in an XMT (Christmas tree) located on the sea bed, is presented. The oilfield tubular (1) is exposed to the production bore (4) pressure, and includes axial sealing means (6) located on an end (1a) of the tubular (1). The axial sealing means (6) includes a metal c-ring seal (6a), which metal c-ring seal (6a) is smaller in cross section than the thickness (t1) of the oilfield tubular wall (1c). The opening (6b) of the metal c-ring seal (6a) is facing the high pressure side of the production bore (4). This pressure tend to expand the c-profile to firm engagement with contacting surfaces.