Swelling Element Packer Circumferential Stress Assembly
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Solution Overview
Problem
Swellable packer elements tend to pull away from the mandrel when exposed to well fluids, creating leak paths and reducing the sealing effectiveness due to residual hoop stresses and inconsistent adhesive application.
Innovation Solution
A vacuum or pressure method is used to induce circumferential stresses in the sealing element during assembly, ensuring it maintains contact with the mandrel and minimizing leak paths during the swelling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing element is allowed to swell freely on exposure to well fluids, then the sealing capability is improved, but the element pulls away from the mandrel creating leak paths
Solution Approach 1:
The patent applies preliminary anti-action by pre-inducing circumferential compressive stresses in the sealing element during assembly on the mandrel. These pre-applied stresses counteract the tensile hoop stresses that develop when the element swells, preventing the element from pulling away from the mandrel and eliminating leak paths while maintaining reliable sealing.
2Reliability
If adhesive is applied to prevent the element from pulling away, then the sealing effectiveness is improved, but the adhesive application becomes inconsistent
Solution Approach 1:
The patent replaces the chemical adhesive system with a mechanical stress system. Instead of relying on inconsistent adhesive bonding, the invention uses controlled mechanical circumferential compressive stresses induced during assembly to prevent radial separation. This mechanical approach provides more reliable and consistent performance than adhesive application.
3Stress or pressure
If the inside diameter of the element is constrained during assembly, then contact pressure is maintained during swelling, but the element cannot expand radially to seal
Solution Approach 1:
The patent applies local quality by creating different stress states in different directions within the sealing element. Circumferential compressive stresses are induced to maintain contact pressure against the mandrel, while the element is simultaneously allowed to expand radially outward to seal against the wellbore or tubular. This directional differentiation of mechanical properties resolves the contradiction between maintaining contact pressure and enabling radial expansion.
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 method effectively prevents the inside diameter of the sealing element from growing away from the mandrel, maintaining a secure seal and eliminating leak paths, even in the presence of well fluids.
Implementation Method 1
elements that swell to a sealing position on exposure to well fluids have been used
Implementation Method 2
A vacuum and a pressure method are described
Implementation Method 3
A vacuum and a pressure method are described
Data Source
AI summary
A sealing element that swells on exposure to well fluids present or added to the wellbore is assembled to the mandrel in a manner to induce circumferential stresses proximately to the inside diameter of the element so as to resist the tendency of the inside diameter of the element to grow during the swelling process. A vacuum and a pressure method are described. Leak paths between the mandrel and the sealing element are minimized or eliminated as a result.