Mechanical Casing Packer Seal Preventing Extrusion
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Solution Overview
Problem
Existing mechanical casing packers face issues with deformation and leakage due to extrusion of packer material through annular gaps during axial compression, leading to inadequate sealing and pressure limitations, especially under high-pressure and chemically aggressive well conditions.
Innovation Solution
A casing packer seal arrangement featuring a sliding assembly with conical inner rings and expanding rings that prevent extrusion by radially expanding and engaging with packer element rings, using a combination of conical ramp faces and plane ring surfaces to maintain a secure seal against the surrounding casing pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axial compression is applied to set the packer, then the packer expands to seal against the casing, but the packer material extrudes through annular gaps causing deformation and leakage
Solution Approach 1:
The packer element is divided into multiple segments or blocks that can compress independently. This segmentation prevents material extrusion by allowing each segment to compress uniformly, maintaining structural integrity while achieving the necessary expansion for sealing against the casing.
Solution Approach 2:
A compression ring is introduced as an intermediary component between the setting mechanism and the packer element. This compression ring distributes the axial compression force uniformly across the packer element, preventing localized stress concentrations that would cause material extrusion through annular gaps.
2Stress or pressure
If the packer is designed to withstand high pressure, then sealing capability improves, but the structure becomes more complex and prone to deformation
Solution Approach 1:
The packer element incorporates regions of varying density and compressibility - harder, less compressible regions provide structural support for pressure resistance, while softer, more compressible regions allow for expansion and sealing. This local differentiation of material properties enables high pressure resistance without requiring complex overall structure.
Solution Approach 2:
The packer element uses composite material construction combining materials with different mechanical properties. This allows the structure to simultaneously achieve high pressure resistance through rigid components and sealing capability through compliant components, avoiding the need for overly complex designs.
3Reliability
If the packer material is made softer to prevent extrusion, then sealing improves, but the packer loses structural strength under high pressure
Solution Approach 1:
Dividing the packer into segments allows different material properties in different regions. Harder segments maintain structural strength while softer segments provide sealing capability, resolving the contradiction between softness for sealing and hardness for strength.
Solution Approach 2:
Different regions of the packer element have different material properties - softer regions for sealing contact and harder regions for structural support. This local quality variation allows the packer to simultaneously achieve good sealing and maintain structural integrity under high pressure.
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 effectively prevents extrusion and maintains a reliable seal under high pressure and aggressive conditions, ensuring a long-lasting, gas-tight seal that withstands pressures up to 10,000 psi and temperatures up to 170°C, with reduced risk of deformation and leakage.
Implementation Method 1
first and second expanding rings (28) each having a conical ramp face (28i) for climbing, thus expanding, on said conical inner rings (7)
Implementation Method 2
first and second expanding rings (28) each having a conical ramp face (28i) for climbing, thus expanding, on said conical inner rings (7)
Data Source
AI summary
A casing packer seal arrangement includes a sliding casing packer seal assembly arranged for being set by axial compression to expand against a surrounding casing pipe, the casing packer seal assembly being compressed and sled along a cylindrical mandrel. The casing packer seal assembly includes at least one packer element ring having mutually opposite, axially outward facing radially inner and outer plane ring portions; first and second conical inner rings having an axially inward directed plane ring face abutting the packer element end rings' inner plane ring portions in their expanded state; first and second expanding rings each having a conical ramp face for climbing, thus expanding, on said conical inner rings, the first and second expanding rings each having a plane, radially outer ring face for engaging, expanding with and supporting the packer element end ring's axially outward facing plane ring portions, so that when expanded, preventing extrusion of the so expanded packer element end ring in an annulus gap between the expanding rings and the surrounding casing pipe.