Acoustic Reflection Wave Separation for Borehole Imaging
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Solution Overview
Problem
Conventional borehole imaging methods face challenges in extracting and enhancing reflection wave data from acoustic logging due to overwhelming direct waves, which limits the ability to accurately image near-borehole geological structures and steer drilling devices effectively.
Innovation Solution
A method and apparatus that separate and enhance reflection wave data by analyzing acoustic data to maximize moveout differences between direct and reflection waves, using techniques such as wave separation and enhancement stacking, and incorporating a priori information about bed inclination to improve imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional borehole imaging methods are used to collect acoustic data, then direct wave data is obtained, but reflection wave data is overwhelmed and cannot be extracted effectively
Solution Approach 1:
The acoustic data is segmented into direct wave components and reflection wave components through wave separation techniques. The method divides the recorded acoustic signal into multiple wavefield components based on their different propagation paths and characteristics, allowing the reflection wave data to be isolated from the overwhelming direct wave background.
Solution Approach 2:
The reflection wave data is extracted from the mixed acoustic signal by removing the direct wave components. The method uses wave separation algorithms to identify and extract the reflection wave portion of the acoustic data, effectively taking out the desired signal from the harmful background.
2Measurement precision
If the distance between signal transmitter and receiver is reduced to enhance moveout difference, then reflection wave separation is improved, but signal strength decreases
Solution Approach 1:
Multiple acoustic signals recorded by different receivers are merged and stacked together. The enhancement stacking process combines signals from multiple receivers that have similar reflection characteristics, thereby amplifying the reflection wave signal strength while maintaining the enhanced moveout difference achieved by the reduced transmitter-receiver distance.
Solution Approach 2:
The method uses periodic transmission of acoustic signals at different transmitter-receiver distances. By alternating between reduced distance (for moveout enhancement) and other distances, and periodically stacking the results, the system maintains signal strength while achieving improved reflection wave separation.
3Measurement precision
If wave separation and enhancement stacking techniques are applied to process acoustic data, then reflection wave data quality is improved, but processing complexity increases
Solution Approach 1:
The wave separation and enhancement stacking operations are performed as preliminary processing steps before final imaging. By preparing the reflection wave data in advance through these processing techniques, the subsequent imaging process becomes simpler and more effective, as the data is already separated and enhanced.
Solution Approach 2:
The processing system uses the inherent characteristics of the acoustic signals themselves (such as moveout differences and wavefield properties) to perform the separation and enhancement. The data essentially processes itself by exploiting its own physical characteristics, reducing the need for complex external processing algorithms.
4Measurement precision
If a priori information about bed inclination is incorporated into the processing, then imaging accuracy is improved, but requirement for additional information increases
Solution Approach 1:
The a priori information about bed inclination acts as an intermediary that guides the wave separation and stacking processes. This additional information serves as a mediator that helps the processing algorithm correctly interpret the acoustic signals and align the reflection waves for enhanced imaging accuracy.
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 significantly enhances the quality of structural images and enables more accurate steering of drilling devices by effectively extracting and enhancing reflection wave data, overcoming the limitations of conventional methods.
Implementation Method 1
transmitting a series of signals into a geological formation from the signal transmitter, and receiving the signals propagating from the signal transmitter with a receiver
Implementation Method 2
The residual data R contains reflection wave data
Data Source
AI summary
A method and apparatus for enhancing the moveout between a direct wave and a reflected wave. The method involves transmitting imaging signals into a body to be imaged and receiving the resulting signals propagated from the signal source. The step of receiving the propagated signals includes selectively adjusting the distance between the signal source and the signal receivers between successive signals. The method further comprises separating the reflected signals from the total received signals and enhanced stacking of the measured reflected signals.