Multi-layer Perforating Gun Body Using Expandable Tubulars
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Solution Overview
Problem
Perforating gun bodies in the downhole drilling and completions industry face excessive swelling and failure due to high forces from setting off charges, limiting the amount of explosives that can be used and resulting in costly fishing operations and lost rig time.
Innovation Solution
A perforating gun body design featuring multiple layers with different yield strengths, where a radially inward layer is expanded to engage a radially outward layer, creating a sealed structure with scallops that enhance ballistic survival characteristics by preventing crack propagation and allowing for increased explosive load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high forces are used to set off charges in perforating guns, then the explosive power and shot density can be increased, but the gun body experiences excessive swelling and failure from cracks
Solution Approach 1:
The gun body is divided into multiple layers (first layer with first yield strength, second layer with second yield strength) having different mechanical properties. This segmentation allows each layer to handle different aspects of the stress - the outer layer resists crack propagation while the inner layer contains the explosive force, thereby increasing both explosive power capability and gun body reliability
Solution Approach 2:
The patent employs composite construction with layers of dissimilar materials having different yield strengths. The first layer (outer) and second layer (inner) are made from materials selected to provide complementary mechanical properties, creating a composite structure that survives high explosive forces while maintaining integrity
2Productivity
If more explosives are used to increase shot density, then productivity improves, but the risk of catastrophic failure increases
Solution Approach 1:
By segmenting the gun body into multiple layers with different yield strengths, the structure can accommodate higher explosive loads without catastrophic failure. The layered design distributes and manages the forces from increased shot density, allowing higher productivity while maintaining safety
Solution Approach 2:
The multi-layer structure acts as a pre-designed protective system that cushions and absorbs the forces from high-density explosives before they can cause catastrophic failure. The layers are configured in advance to handle the expected force spectrum, preventing crack propagation and body failure
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 multi-layer design increases the survivability of perforating guns, enabling higher shot density and explosive load per foot, reducing the risk of catastrophic failure and minimizing manufacturing costs.
Implementation Method 1
the second layer expanded radially to engage the first and second layers
Data Source
AI summary
A perforating gun body including a first layer having a first yield strength and a second layer having a second yield strength, the second layer positioned radially inwardly from the first layer with a radial gap initially provided between the first and second layers, the second layer expanded radially to engage the first and second layers, the first and second yield strengths being dissimilar.