Expandable Isolation Packer with Recessed Sealing Element
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Solution Overview
Problem
Existing packer designs face challenges in protecting the sealing element during run-in while expanding to seal a larger borehole, as they either expose the element to damage or require thinner walls that compromise strength and sealing effectiveness.
Innovation Solution
The packer features projections or bumps in exterior recesses that act as anchors and extrusion barriers, which extend radially upon expansion to support the sealing element, optionally covered with sealing material, and can grow radially from longitudinal shrinkage due to axial or radial expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing element is placed on the mandrel outer diameter, then the packer can be expanded to seal the borehole wall, but the sealing element is exposed to damage during running in
Solution Approach 1:
The sealing element is nested within a recess in the mandrel outer surface, with the recess having a radial depth sufficient to protect the sealing element. The mandrel wall forms a protective cavity that houses the sealing element, shielding it from external damage during run-in while allowing it to expand radially to contact the borehole wall when needed.
2Adaptability or versatility
If the mandrel is expanded from its interior, then the packer can be set in a larger borehole, but the initial internal dimension of the mandrel is limited making expansion more difficult
Solution Approach 1:
The mandrel is designed as an expandable structure that transitions from a compact initial state with limited internal dimension to an expanded state with increased external dimension. The mandrel can be expanded from its interior using conventional expansion tools, allowing the packer to adapt to larger borehole sizes while maintaining ease of run-in through the original smaller dimensions.
3Reliability
If corrugations are used to protect the sealing material during run in, then the mandrel can use thinner wall pipe, but the mandrel becomes weaker and has low differential pressure rating
Solution Approach 1:
The sealing element is nested within a recess in the mandrel outer surface, providing protection during run-in. This approach eliminates the need for external corrugations, allowing the mandrel to maintain its full wall thickness and structural strength while still protecting the sealing element. The recess provides the necessary protection without compromising the mandrel's differential pressure rating.
4Reliability
If the sealing element is placed in a groove that is eliminated during expansion, then the seal can contact the borehole wall, but the sealing material forms thin unsupported strips that roll and fail to provide a reasonable annular seal
Solution Approach 1:
The sealing element is nested within a recess that maintains its structural form during expansion. The recess walls provide continuous support to the sealing element, preventing it from forming thin unsupported strips. As the mandrel expands, the sealing element is pushed radially outward while remaining supported by the recess structure, ensuring it maintains its integrity and forms a stable annular seal against the borehole wall.
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 configuration provides enhanced protection and sealing performance by maintaining a thicker sealing element during run-in and achieving a robust seal against the borehole wall with improved anchoring and pressure retention.
Implementation Method 1
Some designs employ swelling elements to bridge the gap to the borehole wall after exposure to well fluids over a period of time.
Implementation Method 2
Other designs expand the mandrel from within to bring the sealing element to the borehole wall.
Implementation Method 3
Shrinkage from expansion occurs from axial loading in compression from the swage to be advanced
Implementation Method 4
it also occurs as a consequence of radial expansion resulting from advancing of the swage
Data Source
AI summary
An expandable packer features a sealing element in an exterior recess that is straddled by projections or bumps. Upon expansion the bumps move out against the borehole wall as an anchor support. Optionally, the bumps may be covered with a sealing material and may be constructed to assist in their radial movement to the borehole wall as a result of expansion particularly if the mandrel is expanded in compression. The bumps are not necessarily expanded with the swage and their radial growth can be induced from longitudinal shrinkage resulting from radial expansion.