Borehole Seismic Acquisition Using Hydroacoustic Pressure Gradient Measurement
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Solution Overview
Problem
Existing borehole seismic acquisition systems require extensive clamping devices to couple geophones to the borehole wall, which can lead to signal loss and noise interference, and struggle to effectively separate compressional and shear wave components in seismic data.
Innovation Solution
A borehole seismic survey system utilizing a cable with groups of pressure sensors, including hydrophones, to measure transversal and vertical pressure gradients, allowing for the detection of P- and S-wave events without the need for extensive clamping, and transforming pressure measurements into particle velocity data for comprehensive seismic analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If geophones are clamped to the borehole wall, then seismic signal detection is enabled, but signal loss and noise interference occur
Solution Approach 1:
The patent replaces the mechanical clamping system with a hydroacoustic measurement system. Instead of using geophones that must be physically clamped to the borehole wall, the invention uses hydrophones that measure pressure gradients in the borehole fluid. This substitution eliminates the need for mechanical contact with the borehole wall, thereby avoiding signal loss and noise interference associated with clamping while still enabling seismic signal detection through acoustic pressure measurements in the fluid medium.
2Measurement precision
If clamping devices are used to couple geophones to the borehole wall, then seismic data acquisition is possible, but device complexity increases
Solution Approach 1:
The patent eliminates complex mechanical clamping devices by substituting them with a hydroacoustic measurement approach. The system uses hydrophones suspended in the borehole fluid that measure pressure gradients without requiring physical attachment to the borehole wall. This substitution dramatically reduces device complexity while maintaining the capability to acquire seismic data, as the hydrophones can be freely positioned and moved along the borehole without mechanical coupling mechanisms.
3Quantity of substance
If geophones respond to both upgoing and downgoing seismic events, then comprehensive seismic data is obtained, but separation of P- and S-wave components becomes difficult
Solution Approach 1:
The patent segments the seismic wavefield measurement by using multiple hydrophones arranged to measure pressure gradients in different directions. By measuring both the vertical pressure gradient (dp/dz) and horizontal pressure gradient (dp/dx), the system separates the measurement components that correspond to different wave types. This segmentation of the measurement process allows for easier differentiation and separation of P-wave and S-wave components in the recorded data, while still capturing both upgoing and downgoing events.
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 enables accurate and efficient seismic data acquisition with reduced noise and signal loss, allowing for effective separation of P- and S-wave components, enhancing the interpretation of subsurface geological conditions without the need for clamping devices, thus improving the quality and reliability of seismic data.
Implementation Method 1
A borehole seismic survey system utilizing a cable with groups of pressure sensors, including hydrophones, to measure transversal and vertical pressure gradients
Implementation Method 2
A borehole seismic survey system utilizing a cable with groups of pressure sensors, including hydrophones
Implementation Method 3
transforming pressure measurements into particle velocity data for comprehensive seismic analysis
Data Source
AI summary
A borehole seismic acquisition system is described with a plurality of sensors arranged so as to identify within the data measured by the pressure sensors P- and S-wave related signals converted at the boundary of the borehole into pressure waves, the sensors being best arranged in groups or clusters sensitive to pressure gradients in one or more directions.