Perforating Gun Body Design for High Pressure Reliability
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Solution Overview
Problem
Existing perforating guns for subterranean well hydrocarbon production face challenges due to high costs, long lead times for specialized materials, and reliability issues under high hydrostatic pressures, as well as the need for expensive packing processes and detonation cords that can fail due to voids.
Innovation Solution
A perforating gun design featuring a body with a large outer diameter to small inner bore ratio, using commercially available materials like K-55 steel or zinc alloys, which includes inner bore and shaped charge cavities with fluid escape ports and explosive material, eliminating the need for detonation cords and separate liners, and incorporating explosive boosters and compaction devices for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a hollow body with large inner diameter is used to accommodate shaped charges, then the shaped charges can be properly positioned, but the wall thickness becomes relatively thin reducing structural strength
Solution Approach 1:
The hollow body is made from high yield strength materials (150,000 to 200,000 psi) that allow thin walls to maintain structural integrity. This composite approach combines the geometric requirement for large inner diameter with material science to achieve both volume and strength requirements simultaneously.
2Strength
If very high yield strength materials are used for the hollow body, then the structure can withstand high hydrostatic pressures, but the cost and lead time increase significantly
Solution Approach 1:
The patent specifies a yield strength range (150,000 to 200,000 psi) rather than a single extreme value, allowing manufacturers to select from multiple steel grades. This parameter optimization balances structural requirements with manufacturing accessibility, reducing both cost and lead time while maintaining adequate strength.
3Ease of operation
If detonation cords are used to energize shaped charges, then the charges can be initiated, but voids in the fabric tube can cause failure under high pressure
Solution Approach 1:
The patent removes the detonation cord from the system entirely, replacing it with direct initiation methods. This extraction eliminates the reliability issue of fabric tube voids while maintaining the ability to initiate shaped charges, as the initiation system is integrated directly into the charge holder structure.
4Adaptability or versatility
If metal liners are used to hold shaped charges, then the charges can be contained, but expensive packing processes at very high pressures are required
Solution Approach 1:
The charge holder structure is merged with the hollow body wall, eliminating the need for separate metal liners. The shaped charges are contained within recesses formed directly in the hollow body, which simplifies the manufacturing process and eliminates expensive high-pressure packing operations while maintaining secure charge containment.
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 reduces manufacturing complexity, increases reliability, and enhances detonation energy efficiency while using off-the-shelf materials, minimizing the need for specialized components and reducing the risk of failure under high pressure conditions.
Implementation Method 1
The shaped charges include an explosive material and are in communication with a detonating cord. Upon detonation the shaped charges produce explosive jets that cause penetration of the hollow body containing the shaped charges, the well casing wall (the exterior cement if used), and the adjacent formation to some degree.
Implementation Method 2
a shaped charge perforating gun apparatus for generating perforations within a well casing
Data Source
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AI summary
A perforating gun, perforating gun system, and method for producing the same is provided. The perforating gun includes a body and at least one cavity liner. The body has an axial length extending between a first axial end and a second axial end, and an outer radial surface extending between the first and second axial ends, an inner bore, and at least one shaped charge cavity disposed in the outer radial surface. The at least one shaped charge cavity is in fluid communication with the inner bore. The at least one cavity liner is disposed in the shaped charge cavity and is configured to retain an explosive material within the shaped charge cavity.