Bi-directional Frac Plug Grip Ring with Asymmetric Rake Angles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fracturing plugs in the oil and gas industry require extensive drilling to access the full wellbore after use, due to their long axial lengths and complex retrieval processes, which complicates subsequent operations.
Innovation Solution
A frac plug design featuring an upper and lower mandrel with a radially outward sealing element and grip ring, including gripping elements at different rake angles to securely engage the wellbore, allowing for efficient sealing and gripping without upward or downward movement, facilitating easier retrieval by reducing drilling requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional frac plugs are used with long axial lengths, then reliable sealing and gripping are achieved, but extensive drilling is required to access the full wellbore after use
Solution Approach 1:
The grip ring is segmented into multiple grip elements that can be distributed around the wellbore circumference, allowing the plug to achieve reliable gripping function with a shorter axial length. The segmentation enables the gripping force to be distributed across multiple contact points rather than requiring a long axial engagement.
Solution Approach 2:
The grip elements are positioned at different rake angles (orientations) around the wellbore circumference rather than along the axial direction. This dimensional redistribution allows the plug to achieve reliable gripping through circumferential distribution of grip elements, reducing the axial length required while maintaining gripping reliability.
2Reliability
If slip assemblies move outward to grip the wellbore wall, then the frac plug sets securely, but the axial length increases requiring more drilling
Solution Approach 1:
The slip assembly is divided into multiple slip elements that can engage the wellbore wall at different circumferential positions. This segmentation allows secure setting to be achieved through distributed engagement points, reducing the axial length required compared to a single long engagement surface.
Solution Approach 2:
The slip elements engage the wellbore wall in a circumferential distribution pattern rather than requiring extended axial engagement. By utilizing the circumferential dimension for setting security, the axial length of the frac plug can be reduced while maintaining reliable setting.
3Reliability
If the grip ring uses gripping elements at different rake angles, then bi-directional gripping engagement is achieved preventing upward and downward movement, but device complexity increases
Solution Approach 1:
The grip elements are positioned at asymmetric rake angles relative to the horizontal plane, with some elements having positive rake angles and others having negative rake angles. This asymmetric arrangement enables bi-directional gripping capability, preventing both upward and downward movement of the plug. The asymmetric geometry allows each grip element to engage the wellbore wall in a specific direction, providing stability against bidirectional forces.
Solution Approach 2:
The grip ring structure is designed to perform multiple functions: it provides gripping engagement, prevents axial movement in both directions, and maintains plug position during pressure differentials. By integrating these multiple functions into a single grip ring component rather than separate assemblies, the overall device complexity is reduced while achieving reliable bi-directional gripping.
Data Source
AI summary
A frac plug for use in a wellbore includes an upper mandrel with an axis extending therethrough and a lower mandrel that moves axially along the axis and towards the upper mandrel. The frac plug further includes a sealing element and a grip ring that move radially outward from the axis and into engagement with the wellbore. The grip ring includes a first gripping element positioned at a first rake angle with respect to the axis to prevent upward movement of the grip ring with respect to the wellbore when in gripping engagement with the wellbore, and a second gripping element positioned at a second rake angle with respect to the axis that is different from the first rake angle to prevent downward movement of the grip ring with respect to the wellbore when in gripping engagement with the wellbore.