Expandable Packer Sealing Element with Non-Uniform Outer Diameter
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Solution Overview
Problem
Conventional expandable tubing solutions for sealing in wellbores often result in localized and unreliable seals due to the spring back effect, leading to low seal pressure and inadequate sealing performance.
Innovation Solution
The use of a sealing element with a non-uniform outer diameter, featuring alternating thick and thin bands, which expands differently to create undulations in the tubing, enhancing sealing performance by increasing collapse resistance and reducing elastic recovery effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional expandable tubing with uniform sealing elements is used, then the structure is simple and easy to manufacture, but the sealing pressure is low and unreliable due to spring back effect
Solution Approach 1:
The sealing element employs varying thickness along its length, with thicker sections at ends and thinner sections in the middle, creating localized differences in expansion behavior. This non-uniform thickness distribution allows different portions of the sealing element to perform different functions: end sections provide structural support while middle sections create enhanced sealing contact, thereby improving overall sealing reliability without requiring complex multi-component structures
Solution Approach 2:
The sealing element is divided into distinct thick and thin bands or sections along its length. This segmentation creates zones with different mechanical properties that expand at different rates when the tubing is expanded, generating undulating contact patterns that improve sealing reliability while maintaining a relatively simple monolithic structure
2Stress or pressure
If uniform thickness sealing element is used, then manufacturing is simple, but seal pressure is low due to elastic recovery
Solution Approach 1:
By creating local variations in thickness within the sealing element, the design achieves higher seal pressure in critical areas without requiring complex manufacturing processes. The thicker end sections are easier to manufacture while the thinner middle sections create the necessary compliance for high-contact-pressure sealing, resolving the contradiction between manufacturing simplicity and seal pressure generation
Solution Approach 2:
The sealing element's thickness parameter is deliberately varied along its length rather than kept uniform. This parameter change creates zones of different stiffness that expand differently, with thinner sections providing greater compliance and higher contact pressure against the wellbore, thereby increasing seal pressure while maintaining manufacturability through a single integrated component
3Strength
If thicker sealing bands are used throughout, then structural strength is improved, but expansion uniformity decreases and sealing effectiveness is reduced
Solution Approach 1:
The sealing element strategically places thicker sections at the ends for structural strength and support, while using thinner sections in the middle to enable greater expansion and better sealing contact. This local differentiation of thickness allows the structure to maintain overall strength while achieving non-uniform expansion patterns that improve sealing effectiveness
Solution Approach 2:
By segmenting the sealing element into thick end bands and thin middle bands, the design creates distinct functional zones: the thick ends provide structural integrity and anchor points, while the thin middle sections expand more readily to create undulating contact with the wellbore, thereby maintaining both strength and expansion versatility
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
This approach significantly improves sealing pressure and durability, achieving higher seal pressures and maintaining them over time, even at elevated temperatures, compared to conventional methods.
Implementation Method 1
reducing elastic recovery effects
Implementation Method 2
spring back effect resulting in low seal pressure
Data Source
AI summary
Methods and apparatus include an expandable packer having a tubing expanded to create a seal in an annulus surrounding the tubing. The tubing includes a non-uniform outer surface configured to cause formation of undulations in a diameter of the tubing upon expansion of the tubing. A plurality of expandable packers may be connected to a tubular string to isolate multiple zones in a wellbore. A production tubular equipped with multiple expandable packers may be installed in the tubular string. The expandable packers may also include non-uniform outer surfaces configured to form undulations upon expansion. The combination of tubular string and production tubular may be used in an enhanced oil recovery application such as injecting steam into a formation to enhance production.