Big Gap Element Sealing System With Grooved Packing
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Solution Overview
Problem
Conventional element sealing systems for wellbore tools fail to create a seal when the cross-sectional thickness of the gap between the outer diameter of the liner and the inner diameter of the surrounding casing is greater than the pre-set thickness of the packing element.
Innovation Solution
The proposed element sealing system includes a packing element with a groove that forms a double hump configuration upon compression, accompanied by multiple back-up rings with offset slots, allowing the packing element to radially expand and form a seal even when the gap thickness exceeds the packing element's thickness, preventing extrusion and ensuring a consistent seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional element sealing system with a packing element is used, then the system can create a seal when the gap thickness is less than or equal to the packing element thickness, but the system fails to create a seal when the gap thickness exceeds the packing element thickness
Solution Approach 1:
The packing element is segmented into multiple sections by grooves, allowing it to form a double hump configuration that can adapt to varying gap thicknesses. This segmentation enables the packing element to deform and expand radially in a controlled manner, creating effective seals in gaps larger than the original packing element thickness.
Solution Approach 2:
The packing element transitions from a static configuration to a dynamic one, forming a double hump configuration upon compression. This dynamic transformation allows the packing element to adapt its shape and size to match the gap dimensions, enabling sealing in variable gap conditions.
2Reliability
If the packing element thickness is increased to seal larger gaps, then the sealing capability for large gaps is improved, but the system becomes unable to seal smaller gaps effectively and the device complexity increases
Solution Approach 1:
The packing element is divided into multiple segments by grooves, allowing it to form a double hump configuration. This segmentation enables a single packing element of standard thickness to effectively seal larger gaps without increasing the original packing element dimensions or overall system complexity.
Solution Approach 2:
The packing element utilizes radial expansion in the radial dimension to seal larger gaps, rather than increasing the axial thickness. This dimensional transformation allows the packing element to adapt to larger gaps while maintaining its original thickness and avoiding increased system complexity.
3Reliability
If multiple back-up rings with slots are added to prevent extrusion, then the sealing reliability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The back-up rings are designed with slots that segment the ring structure, allowing controlled radial expansion while preventing extrusion. This segmentation provides the necessary sealing integrity through a relatively simple manufacturing process.
Solution Approach 2:
The back-up rings function as flexible structures that can expand radially to contact the casing and prevent extrusion of the packing element. This flexible design provides enhanced sealing reliability without requiring complex rigid structures.
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 enables the sealing system to effectively create a seal in gaps with a cross-sectional thickness up to twice the packing element's thickness, providing pressure integrity and preventing gas migration, even under high temperature and pressure conditions.
Implementation Method 1
the packing element is adapted to form a double hump configuration upon compression
Implementation Method 2
radially expanding the back-up rings into contact with the tubular string
Data Source
AI summary
A sealing system includes a packing element having a groove in a surface thereof. The packing element is adapted to form a double hump configuration upon compression. The sealing system may include a first ring member disposed a first end of the packing element, a second ring member is disposed at a second end of the packing element, a first seal ring is disposed laterally outward of the first ring member, and a second seal ring is disposed laterally outward of the second ring member. A first inner back-up ring is disposed laterally outward of the first seal ring. The first inner back-up ring includes slots. A first outer back-up ring is disposed adjacent the first inner back-up ring and includes slots, wherein that slots in the first outer back-up ring are offset from the slots in the first inner back-up ring.