Dissolvable Bridge Plug Wedge Expansion
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Solution Overview
Problem
Conventional dissolvable bridge plugs in oil and gas well drilling operations result in a smaller casing diameter and are weaker than non-dissolvable materials, leading to increased costs and material intensity due to the need for larger and more complex assemblies.
Innovation Solution
A dissolvable bridge plug assembly featuring a tee bushing, coned bushing, and an expandable molded assembly with an elastomer seal, which expands via a wedge action to effectively seal the well casing and then dissolve, restoring the original casing diameter without additional intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional dissolvable bridge plugs are used to avoid milling operations, then intervention costs are reduced, but the casing diameter becomes significantly smaller than the original diameter
Solution Approach 1:
The bridge plug incorporates an expandable molded assembly with a conical section that transforms from a compact initial position to an expanded set position, dynamically adjusting its outer diameter to match the casing inner diameter. This dynamic expansion capability allows the plug to provide full-bore isolation without permanently reducing casing diameter, resolving the contradiction between cost-effective dissolvable plugs and maintaining casing diameter.
Solution Approach 2:
The plug utilizes parameter changes in the form of radial expansion, where the molded assembly and seal expand outward by a wedge action of the conical section. This parameter change enables the plug to transition from a small packaged state to a full-diameter sealing state, achieving both cost efficiency and full casing diameter restoration.
2Ease of operation
If dissolvable materials are used to create removable bridge plugs, then well intervention complexity is reduced, but the material strength becomes weaker than non-dissolvable materials
Solution Approach 1:
The bridge plug employs composite construction combining a rigid molded assembly made from dissolvable material with an elastomeric seal. This composite approach allows the structural components to provide necessary strength while the elastomer provides sealing capability, overcoming the weakness of pure dissolvable materials while maintaining ease of operation.
Solution Approach 2:
The plug is divided into functional segments: a rigid molded assembly for structural integrity and positioning, and a separate elastomeric seal for sealing. This segmentation allows each component to be optimized for its specific function, with the rigid portion providing strength and the elastomer providing sealing, resolving the strength limitation of dissolvable materials.
3Reliability
If dissolvable bridge plugs are designed to be material intensive to compensate for weakness, then sealing effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The elastomeric seal functions as a flexible element that conforms to the casing inner surface, providing effective sealing without requiring excessive material. The flexibility of the elastomer allows it to create a reliable seal with minimal material thickness, improving sealing effectiveness while reducing device complexity and cost.
Solution Approach 2:
The elastomeric seal acts as an intermediary between the rigid molded assembly and the casing wall, providing the sealing function. This intermediary approach allows the rigid structure to provide positioning and expansion force while the elastomer provides the actual sealing contact, achieving effective sealing with reduced overall material requirements.
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 solution provides effective sealing with reduced component size and material usage, lowering costs by allowing the well casing to reopen to its original diameter without milling, thus addressing the deficiencies of conventional dissolvable bridge plugs.
Implementation Method 1
a wedge action of the conical section results in expansion of the molded assembly and the seal
Implementation Method 2
the elastomer filling in gaps between segments of the slip assembly having thus expanded
Implementation Method 3
the components of the bridge plug assembly are made of dissolvable materials, and over time, the bridge plug assembly dissolves
Data Source
AI summary
A bridge plug assembly includes a tee bushing including a base and a stem, a coned bushing having a conical section and defining a bore that is configured to receive the stem, a molded assembly that is moveable over the conical section from an initial position to a set position, and a seal. The conical section is configured as a wedge such that when the stem is forced into the conical section during a setting process, the molded assembly and the seal move over the conical section from the initial position to the set position and expand radially outward by a wedge action of the conical section against a well casing. The molded assembly includes a slip assembly having a plurality of slip segments, over-molded with an elastomer. All components are made of dissolvable materials so as to reopen the well casing over time to its original inner diameter.