Sealed Ignition System for Subterranean Stimulation Tools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional propellant stimulation tools for subterranean formations face issues with fluid intrusion into the ignition system, compromising their functionality and reliability, especially in well bores with varying diameters, orientations, and extreme temperatures, due to inadequate sealing and mechanical strength.
Innovation Solution
A stimulation tool comprising a first and second tube with an annular volume, where the second tube interior is sealed from the first tube interior to prevent fluid communication, and a propellant member positioned within the first tube, with an ignition propagator that maintains the detonator cord free from fluid contact, ensuring effective ignition and controlled burn rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional propellant stimulation tool uses an open-ended sleeve around the detonator cord, then the detonator cord can be easily placed within the tool, but the ignition system is vulnerable to fluid intrusion from the surrounding environment
Solution Approach 1:
The patent employs a flexible membrane seal that closes the end of the detonator cord sleeve, creating a fluid-tight barrier while accommodating the cord's presence. This flexible film approach prevents well bore fluids from intruding into the ignition system while maintaining the ease of cord placement.
Solution Approach 2:
The patent introduces a fluid-resistant tape wrap as an intermediary layer between the detonator cord sleeve and the well bore environment. This tape acts as a mediator that blocks fluid intrusion paths while allowing the ignition system to function normally.
2Device complexity
If the propellant stimulation tool lacks a reusable metal carrier, then the tool structure is simpler, but the tool cannot withstand excessive forces in small diameter, deviated, or high temperature well bores
Solution Approach 1:
The reusable metal carrier serves multiple functions: it provides structural strength to withstand excessive forces in challenging well bores, acts as a fluid barrier to prevent fluid intrusion, and supports the propellant body during placement and operation. This multi-functional component resolves the contradiction between simplicity and strength.
3Reliability
If fluid resistant tape is wrapped around the ignition system connection, then contact between the ignition system and well bore fluids is reduced, but the sealing effectiveness is insufficient to fully protect against fluid intrusion
Solution Approach 1:
The patent uses a flexible membrane seal that provides superior fluid tightness compared to tape wrapping. This membrane creates a continuous barrier that fully seals the ignition system from well bore fluids, enhancing protection while maintaining relatively simple construction.
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 tool maintains the ignition system dry across a broad range of well bore conditions, enhancing the reliability and repeatability of propellant burns, and effectively stimulates the subterranean formation by preventing fluid intrusion and ensuring consistent performance.
Implementation Method 1
a propellant member and ignition system... a propellant is ignited locally to generate a gas which pressurizes the production interval
Implementation Method 2
The resulting gas creates and propagates fractures in the formation at the production interval of the well bore
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An apparatus for stimulating a subterranean formation includes a first tube, a second tube, a combustion body and an ignition propagator. The second tube is positioned within the first tube interior and the second tube interior is sealed from the first tube interior to substantially prevent fluid communication between the first tube interior and the second tube interior. The combustion body is formed from a solid propellant and is positioned within the first tube interior external to the second tube interior. The ignition propagator is positioned within the second tube interior and is substantially free from fluid contact with fluid residing in the surrounding environment external to the first tube wall.