Perforating Gun Sacrificial Fill for Hoop Stress Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high hoop stress generated during perforating gun detonation can lead to deformation, fracture, and failure of tubular members, making retrieval difficult and increasing operational costs and risks of well abandonment.
Innovation Solution
Incorporating a sacrificial fill material within the perforating gun's internal cavities to redistribute and dissipate pressure, reducing hoop stress and reinforcing the detonation area, thereby using lower-strength materials without compromising the gun's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high explosive pressure is applied to create perforations, then perforation effectiveness is improved, but hoop stress exceeds yield strength causing gun failure
Solution Approach 1:
The patent applies beforehand cushioning by filling the internal cavity with sacrificial fill material that has lower yield strength than the tubular bodies. This sacrificial material is positioned in advance to absorb and redistribute hoop stress during detonation, preventing stress concentration at the tubular bodies and enabling them to withstand the explosive pressure without failure.
Solution Approach 2:
The sacrificial fill material acts as an intermediary element between the explosive pressure source and the tubular bodies. It mediates the stress transmission by absorbing and redistributing hoop stress, thereby protecting the tubular bodies from direct exposure to maximum stress while still allowing effective perforation to occur.
2Strength
If higher strength materials are used for tubular bodies, then resistance to hoop stress is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent applies local quality by using different material strengths in different locations: the sacrificial fill material has lower yield strength and is positioned in the internal cavity where stress concentration occurs, while the tubular bodies can use standard strength materials. This localized differentiation of material properties optimizes both performance and complexity.
3Reliability
If tubular bodies are deformed during detonation, then perforation is achieved, but retrieval becomes difficult requiring fishing tools
Solution Approach 1:
The sacrificial fill material serves as a disposable element that is intentionally designed to be consumed or deformed during the perforation process. It sacrifices itself by absorbing stress and preventing deformation of the valuable tubular bodies, thereby maintaining retrieval ease while still achieving effective perforation.
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
Reduces the risk of buckling failure, fracture propagation, and gun sticking in the wellbore, enhancing the likelihood of successful perforation and reducing non-productive time and remedial operations.
Implementation Method 1
the sacrificial fill material redistributes, or dissipates, most of the misdirected pressure away from the vulnerable tubular components of the perforating gun
Implementation Method 2
the sacrificial fill material absorbs energy from the firing to reduce hoop stress on the gun body
Data Source
AI summary
In general, in one aspect, embodiments relate to a perforating gun that includes a gun body, a charge tube disposed within the gun body, a plurality of charge cases disposed within the charge tube, and a sacrificial fill material disposed within at least a substantial portion of an inner cavity of the charge tube.