Disintegrating Plug for Subterranean Fracturing
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Solution Overview
Problem
Existing barrier plugs for subterranean fracturing operations require milling out after use, leaving residue and necessitating non-degradable components for sealing, which complicates subsequent operations.
Innovation Solution
A disintegrating plug design utilizing external ribs made from degradable materials for frictional contact and optional o-ring seals with hardened inserts for anchoring, allowing for complete removal and minimizing residue after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional non-degradable barrier plugs are used for fracturing operations, then reliable sealing and anchoring are achieved, but milling out is required after use leaving residue and complicating subsequent operations
Solution Approach 1:
The plug body material parameters are changed from non-degradable to degradable, allowing the plug to disintegrate after serving its sealing and anchoring function. This resolves the contradiction by maintaining reliability during use while eliminating the need for milling out and residue removal in subsequent operations.
Solution Approach 2:
The plug is designed as a disposable component that is discarded after its functional life. The degradable plug body is intentionally left to disintegrate in the wellbore, eliminating the need for recovery operations like milling out, thereby simplifying subsequent operations while maintaining sealing reliability during the fracturing process.
2Loss of substance
If degradable materials are used for the plug body, then complete removal is achieved minimizing residue, but sealing capability may be compromised
Solution Approach 1:
The plug is segmented into degradable and non-degradable components. The plug body is made degradable to minimize residue, while separate non-degradable sealing elements (o-rings, seals) are incorporated to maintain sealing capability. This segmentation allows each component to fulfill its specific function without compromise.
Solution Approach 2:
The plug uses composite construction combining degradable materials for the plug body with non-degradable materials for sealing components. This composite approach allows the degradable portion to minimize residue while the non-degradable sealing elements maintain reliable sealing capability throughout the fracturing operation.
3Strength
If hardened inserts are used for enhanced wall penetration and grip, then anchoring capability is improved, but non-degradable residue remains
Solution Approach 1:
The anchoring system is segmented into temporary and permanent components. Expandable ribs provide temporary anchoring during the fracturing operation and are designed to disintegrate with the plug body, while hardened inserts provide enhanced grip and are separated as minimal non-degradable residue. This segmentation reduces overall residue compared to using hardened inserts throughout the entire plug structure.
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
Enables efficient and residue-free plug removal after fracturing operations, reducing the need for milling and minimizing non-degradable components, while maintaining adequate sealing and anchoring capabilities.
Implementation Method 1
The ribs retain the body to the surrounding tubular wall with frictional contact
Data Source
AI summary
A disintegrating plug uses a setting tool to push a swage into the plug body that has external ribs that contact the wall of the surrounding tubular. The ribs retain the body to the surrounding tubular wall with frictional contact. Some leakage may ensue but in fracturing some leakage does not matter if enough volume under the right pressure reaches the formation. The sheared member during the setting comes out with the mandrel that is part of the setting tool. In an alternative embodiment one or more o-rings are used to seal while anchoring is assisted by the hardened insert(s) that can be snap fitted in using rib flexing or that can be a c-ring that is expanded and snapped in. The o-ring(s) are axially spaced from the insert(s).