Downhole Seismic Source Array for Energy Attenuation
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Solution Overview
Problem
Current seismic sources, both surface and downhole, face limitations such as limited frequency bandwidth, high cost, reliability issues in rugged environments, and attenuation of energy as it passes through near-surface layers, which hinder effective subsurface imaging and oil/gas exploration.
Innovation Solution
A linear array of orbital vibrators is deployed within a wellbore, secured with low friction rollers and cemented or connected via drill pipe/tubing, providing improved acoustic coupling and power transmission with a separable topside electronics unit for synchronization and power supply, enabling efficient seismic surveys with enhanced resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If surface seismic sources (vibroseis trucks) are used, then power output is sufficient, but energy is heavily attenuated by near-surface layers and frequency bandwidth is limited
Solution Approach 1:
The patent introduces an intermediate medium (coupling fluid or cement) between the downhole seismic source and the wellbore wall to improve acoustic coupling. This intermediary transfers vibrational energy more efficiently from the source to the surrounding formation, reducing energy loss while maintaining broad frequency bandwidth capability
Solution Approach 2:
The patent replaces traditional mechanical coupling methods (direct contact) with fluid-based acoustic coupling. The coupling fluid fills the annular space between the source and wellbore, providing superior acoustic impedance matching and energy transmission across a wider frequency range
2Measurement precision
If downhole seismic sources are deployed, then near-surface attenuation is bypassed and resolution is improved, but power output is limited to prevent damage to well casings
Solution Approach 1:
The patent segments the seismic source into multiple independent vibrators arranged in an array within the wellbore. Each vibrator operates at lower power individually, but collectively they produce high-resolution seismic signals. This segmentation allows bypassing near-surface attenuation while distributing power requirements across multiple lower-power elements
Solution Approach 2:
The patent combines multiple low-power downhole vibrators into a coordinated array system. By synchronizing the operation of multiple vibrators, the system achieves the cumulative acoustic energy needed for high-resolution imaging without requiring any single source to exceed power limits that would damage well casings
3Adaptability or versatility
If downhole sources are moved to multiple locations via wireline, then survey flexibility is achieved, but operational cost and complexity increase
Solution Approach 1:
The patent creates a dynamic, reconfigurable seismic survey system where the downhole source array can be electrically reconfigured and repositioned along the wellbore using wireline deployment. This allows the same physical hardware to adapt to different survey requirements by changing its operational configuration rather than requiring multiple fixed installations
4Productivity
If downhole sources require periodic maintenance and wireline deployment, then operational flexibility is maintained, but productivity and operational cost decrease
Solution Approach 1:
The patent designs the downhole source array with self-contained power supplies, control electronics, and coupling mechanisms that eliminate the need for periodic wireline interventions. The system serves itself by maintaining operational capability through integrated battery power and autonomous control, significantly improving productivity and reducing operational costs while maintaining reliability in rugged downhole environments
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 significantly increases the spatial/temporal resolution of subsurface imaging, reduces energy attenuation, and allows for permanent installation, reducing operational costs and improving survey efficiency by eliminating the need for frequent maintenance and external resources.
Implementation Method 1
seismic sources are used to introduce controlled acoustic waves into the subsurface
Implementation Method 2
secured with low friction rollers
Implementation Method 3
secured with low friction rollers and cemented or connected via drill pipe/tubing, providing improved acoustic coupling
Data Source
AI summary
A multitude of seismic sources are formed into a linear array which can be permanently cemented within a wellbore. The seismic sources can be orbital vibrators that are electrically connected and protected from the cementing by use of pieces of drill pipe and tubing that are interconnected and provide a container for electrical connection of the seismic sources and provide surface access through a surface vault.