Shaped Charge Outer Case Fragmentation Control
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Solution Overview
Problem
Existing shaped charges used in subterranean perforation operations generate excessive debris and rapid pressure rise, which obstructs production and tool passage, particularly in horizontal wells, due to their fragmentation and detonation characteristics.
Innovation Solution
The design of shaped charges with predefined fracture lines, composite outer cases, and specific material compositions that break apart into low-debris fragments upon detonation, minimizing impact forces on the gun body and reducing pressure rise, includes grooves in solid metal cases, coupled elements, and metal matrices with dispersed particles to control fragmentation and optimize perforation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If zinc alloy is used for shaped charges to reduce debris, then debris fragmentation is reduced, but rapid pressure rise occurs
Solution Approach 1:
The patent changes the physical state parameter of zinc from solid to liquid by controlling detonation conditions. The zinc outer case is designed to melt and form droplets rather than fragment as solid particles, fundamentally changing the debris generation mechanism while maintaining low debris harmful effects and controlling pressure rise characteristics
Solution Approach 2:
The patent uses composite material structure with zinc outer case combined with explosive filling. The zinc material properties are specifically selected to achieve desired fragmentation control and pressure characteristics when detonated, creating a composite system that balances debris reduction with pressure management
2Productivity
If conventional shaped charges are used, then perforation is achieved, but excessive debris obstructs production and tool passage
Solution Approach 1:
The patent employs zinc material that undergoes phase change to liquid droplets with characteristics similar to porous behavior in terms of flow and distribution. The molten zinc forms fine dispersed droplets that behave differently from solid fragments, reducing obstruction while maintaining perforation effectiveness
Solution Approach 2:
By changing zinc from solid to liquid state during detonation, the patent fundamentally alters the debris characteristics from obstructive solid fragments to flowable liquid droplets that can be more easily managed and removed, thus reducing production and tool passage obstructions
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
This approach reduces debris fragmentation, minimizes gun failure risks, and eliminates rapid pressure rise, enhancing perforation efficiency and reducing downhole problems by controlling the size and impact of fragments, thus improving perforator gun survival and wellbore integrity.
Implementation Method 1
The shaped charges typically include a charge case, a quantity of high explosive, and a liner. In operation, the perforations are made by detonating the high explosive which causes the liner to form a jet of particles and high pressure gas that is ejected from the shaped charge at very high velocity. This jet penetrates the wellbore or tubular string, thereby creating one or more openings
Implementation Method 2
zinc breaks up into very small particles upon detonation and may also change from a solid phase to a gas phase due to chemical reactions downhole
Implementation Method 3
the zinc outer case is operable to break up into a plurality of predefined fragments upon detonation of the explosive material
Data Source
AI summary
A method for forming a perforation is disclosed. The method comprises positioning a perforating gun at a desired location in the formation. The perforating gun comprises a gun body and a charge carrier. The method further comprises disposing one or more shaped charges within the charge carrier. The one or more shaped charges comprise an outer case, an inner liner, and an explosive material retained between the outer case and the inner liner. The outer case of the shaped charge comprises one or more predefined fracture lines. The method further comprises detonating at least one shaped charge, wherein detonating the at least one shaped charge forms one or more perforations in the formation.