Composite Sleeve Mandrel Connection Shear Pin Reinforcement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing composite frac and bridge plugs in oil and gas well operations face challenges in sustaining higher pressures and operating temperatures, necessitating an improved sleeve to mandrel connection for enhanced durability.
Innovation Solution
A composite downhole tool design featuring a composite sleeve and mandrel with adhesive bonding and shear pins to distribute load across multiple laminate layers, providing increased interlaminate shear strength and improved connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If composite materials are used for frac and bridge plugs, then drill-out time is reduced, but the ability to sustain higher pressures and temperatures deteriorates
Solution Approach 1:
The patent employs a composite structure consisting of a composite mandrel and a composite sleeve made from different material compositions. The mandrel uses a first composite material optimized for drill-out properties, while the sleeve uses a second composite material with enhanced pressure and temperature resistance. This multi-material composite approach allows the plug to simultaneously achieve fast drill-out capability and high-pressure/temperature sustainability.
2Ease of manufacture
If adhesive bonding alone is used to connect sleeve and mandrel, then manufacturing is simplified, but connection strength under high pressure deteriorates
Solution Approach 1:
The patent merges two different connection mechanisms: adhesive bonding and mechanical interference fitting. The adhesive layer provides initial bonding and seals the interface, while the tapered pin inserted through aligned holes in both the sleeve and mandrel provides mechanical interlocking. This combination of chemical bonding (adhesive) and mechanical bonding (interference fit) ensures both ease of manufacture and high connection strength under pressure.
Solution Approach 2:
The adhesive layer acts as an intermediary substance between the sleeve and mandrel surfaces, creating a chemical bond that complements the mechanical bond. The adhesive fills micro-irregularities at the interface and distributes stresses, enhancing the overall connection strength while maintaining manufacturing simplicity.
3Ease of manufacture
If the pin hole extends through the entire mandrel thickness, then assembly is simplified, but structural integrity of the mandrel deteriorates
Solution Approach 1:
The pin hole is designed with local quality variation: it extends completely through the sleeve thickness to facilitate assembly, but only partially through the mandrel thickness (stopping before exposing the innermost laminate layers). This localized difference in penetration depth allows easy assembly while preserving the structural integrity of the mandrel's critical inner layers that provide strength and drill-out characteristics.
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 enhances the ability of frac and bridge plugs to withstand higher pressures and temperatures, ensuring reliable zonal isolation and efficient drilling operations by reinforcing the sleeve to mandrel connection with shear pins and adhesive bonding.
Implementation Method 1
an overlapped section that is fixed by adhesive bonding
Implementation Method 2
a shear pin may be located in the pin hole
Data Source
AI summary
A composite downhole tool, such as a frac plug or a bridge plug, having a composite sleeve located around a composite mandrel and defining an overlapping or overlapped section between the two. One or more shear pins with each shear pin having a pin hole is provided with the downhole tool to reinforce the downhole tool from interlaminate shear. The one or more shear pins can further be reinforced from rotation by overlapping at least part of the one or more pins with a lip of a ring.