Frac Plug Wedge Slip Design for Rapid Casing-Safe Removal
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Solution Overview
Problem
Existing frac and bridge plugs are difficult to remove quickly without damaging the well casing, as their slips often do not release properly, leading to increased drilling time and cost, especially in high-cost operations and horizontal well sections.
Innovation Solution
A plug apparatus with an annular wedge and slip design that includes a tapered outer surface and inner surface, a radially expandable sealing ring, and collet fingers to securely anchor and seal within the casing, allowing for efficient setting and retrieval without damaging the casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plugs with cone and slip sets are used to anchor in the casing, then the plug can be securely set and isolated, but the slips do not release properly making removal difficult and time-consuming
Solution Approach 1:
The slip assembly transitions from a static anchored state to a dynamic released state through controlled axial movement. The wedge-shaped cone forces the slips radially outward to jam between the cone and casing for anchoring, then allows radial retraction for release, enabling the plug to be pulled freely through the casing without damage.
Solution Approach 2:
The slip assembly is divided into multiple separate wedge-shaped segments rather than a unitary construction. These segments can be pushed radially into the casing and then released independently, allowing the plug to be removed by simply pulling without requiring milling or drilling operations.
2Loss of time
If plugs are made of materials that drill easily, then drilling time is reduced, but the expense increases
Solution Approach 1:
The invention extracts the need for drilling or milling operations entirely by providing a release mechanism built into the slip assembly. The plug can be removed by simple axial pulling motion after setting, eliminating the need to drill out the plug and avoiding both time loss and special material requirements.
3Ease of operation
If conventional setting tools with rams and annular sleeves are used, then the plug can be set in the casing, but the device complexity increases
Solution Approach 1:
The plug assembly is self-setting through the interaction of its own components. The wedge-shaped cone and slip assembly automatically jam radially outward when axial force is applied during setting, and automatically release when axial force is removed during retrieval, eliminating the need for complex setting tools with multiple actuating members.
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 plug apparatus enables rapid and cost-effective setting and removal of frac plugs, reducing drilling time and minimizing casing damage, while maintaining a simple and inexpensive design.
Implementation Method 1
The wedge has a tapered outer surface adjacent the wedge second end. The tapered outer surface increases in outside diameter from the wedge second end toward but not necessarily all the way to the wedge first end. The wedge second end is received in the slip first end so that the tapered outer surface of the wedge engages the tapered inner surface of the slip.
Implementation Method 2
A sealing ring is received about the tapered outer surface of the wedge. The sealing ring is radially expandable. The sealing element is also pushed radially outward to contact and seal against the inside wall of the casing.
Data Source
AI summary
A compact and simplified frac plug apparatus is provided with improved drillability. The frac plug includes an annular wedge, a sealing ring, and an annular slip. An adapter kit apparatus is provided for connecting the plug assembly to a setting tool. Methods of operation for setting the plug apparatus in a well are also disclosed.