Bridge Plug Slip Segmentation for Milling Removal
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Solution Overview
Problem
Conventional bridge plug designs are difficult to remove as milling leaves large pieces that are hard to circulate out of the flowbore due to their structural integrity.
Innovation Solution
The bridge plug design features a unitary, radially outer contact portion made of hardened cast iron and an inner body portion of easily disintegrable aluminum segments, cast within a phenolic slip ring, with openings creating points of weakness for disintegration during milling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional bridge plug designs are used, then the plug can be set and held in place, but milling through the plug leaves large pieces that are difficult to circulate out of the flowbore
Solution Approach 1:
The slip element is divided into two distinct segments: an outer contact portion made of hardened cast iron and an inner body portion made of aluminum. This segmentation allows the outer portion to maintain structural integrity for setting and holding, while the inner portion is designed to disintegrate during milling for easy removal and circulation.
Solution Approach 2:
Different materials with different properties are used in different regions of the slip element. The outer contact portion uses hardened cast iron for durability and engagement, while the inner body portion uses aluminum for easy disintegration. This local quality differentiation resolves the contradiction between needing structural integrity for setting and ease of removal for milling.
2Reliability
If the bridge plug is made of strong, durable material, then it can effectively seal and hold in place, but it requires excessive milling effort and leaves large pieces
Solution Approach 1:
The slip element is segmented into an outer contact portion for sealing and an inner body portion for structural support that is easily removed. This allows the sealing function to be performed by the durable outer portion while the inner portion is designed for rapid disintegration during milling, improving productivity.
Solution Approach 2:
The slip element uses a composite structure combining hardened cast iron for the outer contact portion and aluminum for the inner body portion. This composite material approach allows the plug to achieve reliable sealing with the cast iron while enabling efficient milling and easy circulation of debris with the aluminum inner portion.
3Ease of manufacture
If the bridge plug is designed as a single unit, then it is simpler to manufacture, but it cannot easily disintegrate during milling operations
Solution Approach 1:
The slip element is manufactured as a composite of two materials (hardened cast iron outer portion and aluminum inner portion) that are cast together. This segmented material approach maintains relative manufacturing simplicity while enabling the inner aluminum portion to easily disintegrate during milling operations.
Solution Approach 2:
The use of composite materials (cast iron and aluminum) allows the slip element to be manufactured as an integrated component with distinct functional zones. The aluminum inner body portion is designed to disintegrate during milling, providing ease of operation without requiring complex assembly or multiple manufacturing steps.
4Strength
If the outer contact portion is made of hardened material, then it can effectively engage the tubular member, but it resists milling and creates larger debris pieces
Solution Approach 1:
The slip element is segmented into a hardened outer contact portion for engagement and a softer inner body portion for easy milling. This segmentation allows the outer portion to maintain high strength for effective tubular member engagement while the inner portion mills quickly, improving overall productivity.
Solution Approach 2:
The outer contact portion is locally optimized with hardened cast iron for high-strength engagement with the tubular member, while the inner body portion is locally optimized with aluminum for easy milling. This local quality differentiation resolves the contradiction between engagement strength and milling speed.
Data Source
AI summary
A design for a bridge plug wherein the slip elements include an outer contact portion to engage a surrounding tubular member and an inner body portion designed to easily disintegrate during removal of the bridge plug by subsequent milling. The inner body portion is formed of a softer material than the outer contact portion. Also, the inner body portion is made up of a plurality of segments that are readily separated and dispsersed during milling out.