Thermoplastic Composite Downhole Tools Hoop Strength
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Solution Overview
Problem
Conventional metallic downhole tools face challenges such as high friction, limited burst and collapse strength, and susceptibility to corrosion in subterranean environments, which affect their performance and longevity.
Innovation Solution
The use of filament-wound thermoplastic composites, where the fiber placement favors hoop strength over axial strength, provides increased collapse and burst strength, reduced friction, and improved corrosion resistance compared to metallic counterparts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic materials are used for downhole tools, then axial strength is adequate, but hoop strength is limited and corrosion resistance is poor
Solution Approach 1:
The patent applies composite materials by combining thermoplastic matrix with fiber reinforcement (such as carbon fibers, glass fibers, or aramid fibers) to create a downhole tool that simultaneously achieves high hoop strength and corrosion resistance. The fiber reinforcement provides the necessary mechanical strength while the thermoplastic matrix offers corrosion protection, resolving the contradiction between strength and reliability in corrosive downhole environments.
2Ease of operation
If metallic materials are used for downhole tools, then manufacturing is straightforward, but friction is high and setting forces are excessive
Solution Approach 1:
The patent changes the material parameters from metallic to thermoplastic composite, which fundamentally alters the friction characteristics. The thermoplastic material provides lower coefficient of friction compared to metals, reducing the setting forces required for packers and other downhole tools. This parameter change resolves the contradiction by prioritizing operational ease while accepting advanced manufacturing processes for composites.
3Strength
If fiber placement favors hoop strength, then collapse and burst strength increase, but axial strength is reduced
Solution Approach 1:
The patent applies local quality by varying the fiber orientation and winding angles at different locations and layers of the downhole tool. By optimizing fiber placement patterns (such as using different winding angles in different layers), the composite structure achieves high hoop strength for collapse and burst resistance while maintaining adequate axial load capacity through strategically placed axial or helical fiber layers.
Data Source
AI summary
A variety of methods and apparatus are disclosed, including, in one embodiment, an apparatus comprising a downhole tool for use in a borehole, the downhole tool comprising a composite of thermoplastic and fibers, wherein the fibers reinforce the thermoplastic, and wherein fiber placement gives the composite as favoring the hoop strength over the axial strength.