Sliding-Piston Downhole Equalizer for Pyrotechnic Pressure Balance
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Solution Overview
Problem
Existing well tools face challenges in withstanding pressure differences during pyrotechnic heat generation processes, leading to potential tool destruction and increased costs due to the use of expensive materials or thick walls, and sudden pressure equalization can disrupt the heat generation process.
Innovation Solution
A downhole pressure equalizer with a piston compartment and sliding piston sections that adjust to equalize pressure differences by moving within the compartment, reducing frictional forces to manage pressure changes during the heat generation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the housing wall thickness is increased to withstand external pressure, then the strength and reliability improve, but the cost and material usage increase
Solution Approach 1:
The housing is divided into two pressure zones by a piston: a first compartment exposed to well pressure and a second compartment maintained at ambient pressure. This segmentation allows the housing to withstand external pressure without requiring increased wall thickness throughout, as only the first compartment needs to be pressure-resistant.
2Reliability
If sudden pressure equalization occurs during pyrotechnic heat generation, then the pressure balance is restored, but the heat generation process is disrupted or stopped
Solution Approach 1:
The piston is pre-positioned to separate the pyrotechnic mixture from the high-pressure environment before ignition. This preliminary arrangement ensures that when heat generation causes pressure increase, the piston can move to equalize pressure gradually without disrupting the combustion process, maintaining both pressure balance and process continuity.
Solution Approach 2:
The piston acts as an intermediary between the pyrotechnic mixture and the external high-pressure environment. It mediates pressure transmission, allowing the heat generation process to proceed undisturbed while still enabling pressure equalization when needed through controlled piston movement.
3Reliability
If expensive high strength materials are used to withstand external pressure, then the reliability improves, but the cost increases
Solution Approach 1:
By segmenting the housing into pressure-exposed and pressure-protected zones, the patent reduces the overall material requirements for pressure resistance. Only the first compartment and piston require high-strength materials, while the second compartment can use standard materials, thereby reducing manufacturing costs while maintaining reliability.
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 pressure equalizer effectively maintains pressure equilibrium before, during, and after the heat generation process, reducing the risk of tool destruction and ensuring consistent operation.
Implementation Method 1
the pressure difference between the fluid pressure in the first sub-compartment and the fluid pressure in the second sub-compartment causes the outer piston section and the inner piston section to move towards the second end of the piston compartment
Implementation Method 2
When the heat generating process is initiated, heat and gas will be produced as part of the process. This will cause the pressure inside the compartment to increase again.
Data Source
AI summary
The present invention relates to a downhole pressure equalizer comprising an elongated housing comprising a piston compartment having a first end provided in fluid communication with an outside of the elongated housing and a second end provided in fluid communication with a process chamber of a well tool. A piston device provided in the position compartment comprises an outer piston section slidingly and sealingly engaged with the piston compartment; and an inner piston section slidingly and sealingly engaged within the through bore of the outer piston section.