Downhole Stimulation Device Shaped Charge Ignition
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Solution Overview
Problem
Conventional downhole stimulation devices using propellant-based and explosive-based systems face inefficiencies due to long ignition periods and slower pressure buildup, which can lead to incomplete fracture expansion and reduced effectiveness when used together, as well as limitations in propellant volume and pressure generation.
Innovation Solution
A downhole stimulation device featuring a housing filled with energetic material and an initiator in the form of a shaped charge that rapidly ignites the material along its length, producing high-pressure gases to stimulate formations, with the shaped charge configured to penetrate the energetic material and generate a projectile for simultaneous ignition and pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional propellant ignition systems using pyrotechnic initiators or small rocket motors are used, then the propellant can be ignited, but the ignition period becomes too long (10-100 milliseconds), causing the propellant to burn sequentially from one end to the other rather than simultaneously
Solution Approach 1:
The propellant grain is segmented into multiple sections along its length, with each section having its own ignition point. Multiple detonation cords are positioned at different locations along the propellant grain, allowing simultaneous ignition of multiple segments rather than sequential burning from a single point.
Solution Approach 2:
The ignition approach transitions from one-dimensional sequential burning (cigarette-type burn from one end) to multi-dimensional simultaneous ignition by introducing detonation cords at multiple positions along the length of the propellant grain, enabling ignition to propagate through the propellant in multiple directions simultaneously.
2Power
If conventional propellant-based stimulation devices are used, then gas can be produced to stimulate formation, but the pressure buildup time is too long, rendering the device ineffective when combined with explosive-based stimulation devices that detonate much faster
Solution Approach 1:
The propellant grain is divided into multiple ignitable segments with detonation cords positioned at different locations. This segmentation allows simultaneous combustion of multiple segments, dramatically increasing the rate of gas production and pressure buildup compared to sequential burning.
Solution Approach 2:
The multi-point ignition system ensures continuous and simultaneous combustion throughout the propellant grain length, maintaining continuous gas generation and pressure buildup without the delays inherent in sequential burning, thereby achieving effective synchronization with explosive detonation.
3Speed
If an axially extending bore is created through the center of the propellant grain to accommodate a detonation cord, then radial burn propagation can be achieved, but the overall propellant volume is reduced, limiting the amount of propellant available for combustion
Solution Approach 1:
Instead of creating a continuous central bore through the propellant grain, detonation cords are positioned in localized regions or embedded within the propellant structure at specific locations. This approach enables radial burn propagation from these localized points while preserving the overall propellant volume and structural integrity.
Solution Approach 2:
The detonation cords are nested within or embedded in the propellant grain structure rather than requiring a separate central bore. This nesting approach allows the ignition system to be integrated within the propellant volume itself, maximizing the use of available space for both ignition mechanisms and propellant material.
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 configuration enables rapid and simultaneous ignition of the energetic material, achieving faster pressure buildup and more effective fracture expansion, allowing for enhanced stimulation of subterranean formations with improved efficiency and reliability compared to conventional systems.
Implementation Method 1
The initiator comprises a shaped charge for igniting the energetic material within the housing. The shaped charge is configured to produce a projectile to penetrate the energetic material in order to ignite the energetic material.
Implementation Method 2
As the propellant grain is initiated, gases from the burning propellant grain exit the housing through holes formed in the housing, entering the producing formation.
Implementation Method 3
The resultant shockwave caused by detonation of the high energy explosive material in the wellbore may be employed to fracture a formation adjacent the wellbore.
Data Source
AI summary
Downhole stimulation devices include an energetic material disposed within a housing and an initiator for igniting the energetic material. The initiator may comprise a shaped charge configured to produce a projectile to penetrate the energetic material to ignite the energetic material. The housing of the device may comprise a continuous outer surface. Methods of operating a downhole stimulation device include initiating an energetic material disposed within a housing of the stimulation device in order to burn the energetic material in a laterally extending direction transverse to a depth of a borehole in which the stimulation device is disposed.