Self Boosting Packer Element Locking Mechanism
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Solution Overview
Problem
Existing downhole packers that swell in response to well fluids struggle to effectively capture and retain differential pressure forces, leading to limitations in sealing capability and potential extrusion of the sealing element.
Innovation Solution
A packer assembly with elements that swell in contact with well fluids, featuring a locking mechanism to retain boost forces from applied loads, utilizing surface treatments and ratchet-like mechanisms to enhance friction and locking of forces in a specific direction, allowing for enhanced sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing element swells radially to form a seal, then the sealing capability is improved, but the sealing element may be extruded in the longitudinal direction
Solution Approach 1:
The sealing element is divided into multiple independent swelling segments or zones along its length. Each segment can swell radially to provide sealing at different positions, while the segmented structure prevents excessive radial swelling from causing longitudinal extrusion by distributing the swelling forces throughout multiple discrete zones rather than allowing uniform expansion along the entire element.
Solution Approach 2:
The sealing element incorporates asymmetric structural features such as varying radial thicknesses, different material properties in different zones, or asymmetric reinforcement patterns. These asymmetric designs allow the element to swell radially to the extent needed for effective sealing while the asymmetric geometry provides resistance to longitudinal extrusion by creating structural imbalance that counteracts the extrusion tendency.
2Force
If the sealing element is compressed into contact with the surrounding tubular, then the contact pressure is increased, but the element length is reduced
Solution Approach 1:
The sealing element utilizes changes in material parameters under pressure, such as viscoelastic properties or pressure-dependent modulus, to maintain adequate contact pressure while minimizing length reduction. The material is selected or formulated to exhibit pressure-hardening or viscoelastic recovery characteristics that allow the element to generate high contact pressures during compression while retaining sufficient length for effective sealing and avoiding excessive shortening.
3Force
If the sealing element swells to form a seal, then the sealing force is enhanced, but the differential pressure control capability is limited
Solution Approach 1:
The sealing element incorporates dynamic characteristics such as time-dependent swelling rates, pressure-responsive material properties, or movable components that adjust the sealing force in response to changing differential pressures. This dynamic behavior allows the element to maintain optimal sealing force across a range of pressure conditions while providing feedback control that enhances differential pressure management capability.
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 captures and retains differential pressure forces, enhancing the sealing force of the packer assembly to withstand greater pressure differentials and prevent extrusion, thereby improving the packer's sealing performance.
Implementation Method 1
elements that respond to the surrounding well fluids and swell to form a seal
Implementation Method 2
utilizing surface treatments and ratchet-like mechanisms to enhance friction and locking of forces in a specific direction
Data Source
AI summary
A packer assembly features one or more elements that preferably swell when in contact with well fluids and have a feature in them that responds to an applied load in a given direction by retaining such a boost force with a locking mechanism. A single element can have two such mechanisms that respond to applied forces from opposed directions. Friction force for adhering the element to the mandrel is enhanced with surface treatments between them that still allow the locking mechanisms to operate.