Expandable Metallic Seal for High-Pressure Well Applications
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Solution Overview
Problem
Existing subterranean well seals face challenges with high pressure resistance, material deformation under stress, and incomplete dissolution of frac plug materials, leading to clogging and reduced effectiveness in hydraulic fracturing applications.
Innovation Solution
A radially expandable metallic seal with alternating slits to minimize stress and a resilient gasket for sealing, allowing for high expansion without plastic deformation and complete dissolution of metallic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If resilient materials such as rubber are used for sealing, then the seal can be readily axially compressed to expand its diameter, but the pressure holding capability is very low due to axial extrusion into the extrusion gap
Solution Approach 1:
The seal is divided into multiple circumferential segments that can independently deform and expand. This segmentation allows the seal to expand radially when axially compressed while preventing axial extrusion, as each segment is constrained by its neighbors. The segmented structure resolves the contradiction by enabling easy compression while maintaining pressure holding capability through the interlocking segment geometry.
2Reliability
If the seal is radially expanded to a larger diameter, then it can operate under higher differential pressure, but internal stresses cause plastic deformation and prevent retraction
Solution Approach 1:
The seal transitions from a static structure to a dynamic one where the circumferential segments can move relative to each other during expansion and contraction. This dynamic configuration allows the seal to expand radially under differential pressure while maintaining the ability to retract, as the segments can flex and return to their original positions. The dynamic design resolves the contradiction by enabling high pressure resistance without permanent deformation.
3Ease of manufacture
If dissolving rubber or rubber-like elements are used in frac plugs, then they can provide sealing, but they do not completely dissolve and may reform as solids at cooler temperatures, creating clogs
Solution Approach 1:
The seal material transitions from organic rubber to inorganic metallic material, fundamentally changing the chemical composition and dissolution behavior. Metallic materials dissolve completely into solution at downhole temperatures and do not reform as solids when cooling occurs, eliminating the clogging problem. This parameter change in material composition resolves the contradiction by maintaining sealing function while preventing harmful solid formation during temperature cycling.
4Reliability
If metallic seal materials are used, then they can resist higher differential pressure and are less prone to nibbling, but the expansion process introduces internal stresses that cause plastic deformation
Solution Approach 1:
The metallic seal is divided into circumferential segments that can independently deform during expansion. This segmentation reduces the internal stresses in each individual segment, preventing plastic deformation while maintaining the overall pressure holding capability. The segmented structure allows controlled elastic deformation distributed across multiple segments rather than concentrating stress in a continuous ring.
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 solution provides a durable, high-pressure seal that minimizes deformation and ensures complete dissolution, reducing clogging risks and maintaining effectiveness across varying temperatures.
Implementation Method 1
the ring is axially compressed so as to radially expand the ring into sealing engagement with the interior surface of the tubular member
Implementation Method 2
A radially expandable metallic seal with alternating slits to minimize stress and a resilient gasket for sealing, allowing for high expansion without plastic deformation
Implementation Method 3
a resilient gasket for sealing, allowing for high expansion without plastic deformation
Data Source
AI summary
A high-pressure capable sealing apparatus and method for sealing against an interior surface of a cylindrical tubular member provides the ability to expand to a larger diameter from a given running diameter and to transition back to the original diameter. The sealing apparatus may include a ring assembly with a metallic ring characterized by a uniform axial cross-sectional profile having an outward-facing convexity and an inward-facing concavity. A plurality of slits may be radially formed through the ring about the outer surface to relieve stress within the ring during radial expansion. A circular resilient gasket may be at least partially coaxially disposed within the ring concavity. The ring assembly may be located between uphole and downhole shoulders, which may be selectively axially movable with respect to one another so as to selectively axially compress and radially expand the ring into sealing engagement with a tubular member.