Fracturable Backup Rings for Seal Extrusion Prevention
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Solution Overview
Problem
Existing seal systems for oil well tubing and casing, such as packers and bridge plugs, face issues with unwanted extrusion of deformable seals, necessitating the need for alternative solutions to prevent seal extrusion and ensure effective sealing and pressure isolation.
Innovation Solution
An integrated seal backup system comprising a guiding mandrel, taper elements, a deformable element, and backup rings that fracture to expand and prevent unwanted extrusion, with the backup rings positioned between the taper elements and the deformable element to ensure complete isolation and containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deformable seal element is used to seal annular areas between concentric tubulars, then effective sealing and pressure isolation are achieved, but unwanted extrusion of the seal occurs
Solution Approach 1:
A deformable backup ring is positioned between the rigid backup ring and the deformable seal element. This intermediate deformable component absorbs the extrusion force, deforms under pressure to fill gaps, and prevents direct contact between the rigid backup ring and seal, thereby eliminating seal extrusion while maintaining sealing effectiveness
Solution Approach 2:
The backup ring system combines rigid and deformable materials in a composite structure. The rigid backup ring provides structural support and positioning, while the deformable backup ring provides compliance and gap-filling capability. This composite approach allows the system to resist extrusion forces without compromising the seal
2Object-generated harmful factors
If rigid backup rings are used to prevent seal extrusion, then seal containment is improved, but gap filling and adaptation to tubular irregularities are reduced
Solution Approach 1:
The backup ring system employs different material properties in different zones: the rigid backup ring provides structural support where needed, while the deformable backup ring provides compliance and gap-filling capability in contact with the seal. This local differentiation of material properties allows simultaneous achievement of extrusion prevention and adaptability
3Reliability
If multiple backup rings are used to enhance seal protection, then extrusion prevention is improved, but device complexity increases
Solution Approach 1:
The backup ring system is divided into functionally distinct segments: a rigid backup ring for structural support and positioning, and a deformable backup ring for compliance and gap-filling. This segmentation allows each component to be optimized for its specific function while working together to provide comprehensive seal protection
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 system effectively prevents unwanted extrusion of seals by using fracturable backup rings that expand radially, ensuring a secure seal against the tubular surface, thereby maintaining fluid pressure isolation and containment.
Implementation Method 1
deforming the deformable element radially outward to seal against the tubular surface
Implementation Method 2
backup ring having an inner taper matching the taper element and adapted to fracture in a pre-determined location in response to a diameter expanding force
Data Source
AI summary
An integrated seal backup system includes a guiding mandrel; opposing taper elements; a deformable element positioned around the mandrel and between the taper elements; opposing sets of rings adjacent the deformable element, each set having an inner solid ring having an outer diameter smaller than an inside diameter of the tubular to be sealed and at least one backup ring having an inner taper matching the taper element and adapted to fracture in a pre-determined location in response to a diameter expanding force.