Wave Manipulator for Electrohydraulic Fracturing
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Solution Overview
Problem
Electrohydraulic fracturing in low-permeability formations is inefficient due to the spherical radiation of shock waves, compression wave character, and acoustic impedance differences between the wellbore fluid and the formation, resulting in limited energy penetration and fracturing effectiveness.
Innovation Solution
The use of a wave manipulator system that channels and converts the acoustic shock wave from a quasi-spherical to a quasi-planar shape, changes its wave character from compressive to expansive, and adjusts its impedance to match the formation, focusing and directing the energy deeper into the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the acoustic shock wave radiates spherically in all directions, then the shock wave can be generated easily by electrohydraulic fracturing device, but the energy disperses rapidly and penetration depth is limited
Solution Approach 1:
The wave manipulator segments the spherical shock wave front into multiple controlled wavefronts using reflective surfaces, transforming the single spherical radiation into directed quasi-planar wave propagation that reduces geometric dispersion and enhances energy concentration at depth
Solution Approach 2:
The invention transforms the shock wave propagation from three-dimensional spherical radiation to two-dimensional quasi-planar wave propagation by using the wave manipulator to flatten and direct the wavefront, thereby reducing energy dispersion in the radial direction and concentrating energy along the propagation path
2Speed
If the shock wave has compressive wave character, then the wave can propagate effectively through the wellbore fluid, but it creates compression stress that is less effective for fracturing rock
Solution Approach 1:
The wave manipulator inverts the stress character of the shock wave by using reflective surfaces to convert the compressive wave into an expansion (tensile) wave, thereby transforming the stress type from compression to tension which is more effective for rock fracturing while maintaining propagation effectiveness
3Ease of operation
If there is acoustic impedance difference between wellbore fluid and formation, then the fluid can be easily pumped into the wellbore, but energy reflections occur at the interface reducing energy penetration
Solution Approach 1:
The wave manipulator acts as an intermediary device at the interface between the wellbore fluid and formation, using its structured reflective surfaces to gradually transition the acoustic impedance and reduce the abrupt impedance mismatch, thereby minimizing energy reflections and maximizing energy transmission into the formation
4Force
If the shock wave energy is concentrated in a small area near the wellbore, then the initial shock intensity is high, but the penetration depth into the formation is limited
Solution Approach 1:
The wave manipulator dynamically adjusts the shock wave propagation characteristics by using movable or adjustable reflective surfaces to control the wavefront shape, maintaining high intensity while extending penetration depth through adaptive wave focusing and directing mechanisms
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 enhances the energy deposition and penetration depth of the shock wave, increasing the effectiveness of fracturing in low-permeability formations by reducing geometric dispersion, converting compressive stress to tensile stress, and mitigating energy reflections, thereby improving the magnitude and depth of fracturing.
Implementation Method 1
electrohydraulic fracturing where a rapid arc discharge or plasma induced by the high voltage takes place in a liquid
Implementation Method 2
The rapid expansion of the arc channel and liquid vaporization and expansion results in outward radiation in all directions of a strong acoustic shock wave
Implementation Method 3
channeling the acoustic shock wave down the wellbore to change a shape of the acoustic shock wave to a quasi-planar shape
Implementation Method 4
converting the compressive wave character to an expansion wave character
Implementation Method 5
changing an acoustic impedance of the acoustic shock wave
Data Source
AI summary
Methods for electrohydraulic fracture stimulation of formations may include producing an acoustic shock wave having a compressive wave character in a wellbore penetrating a formation and manipulating the acoustic shock wave. The acoustic shock wave may be manipulated in one or more of the following steps: channeling the acoustic shock wave down the wellbore to change a shape of the acoustic shock wave to less spherical; converting the compressive wave character to an expansion wave character; and changing an acoustic impedance of the acoustic shock wave. The acoustic shock wave having the changed shape, the expansion wave character, and the changed acoustic impedance is distributed into the formation.