Drill Bit Sound Analysis for Real-Time Geologic Layer Impedance
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Solution Overview
Problem
Existing methods for estimating primary wave (P-wave) seismic impedance and density values of geologic layers during drilling are costly due to the sophisticated equipment required for logging while drilling (LWD).
Innovation Solution
Utilizing drill bit sound to evaluate density and seismic impedance values by processing acoustic signals generated during drilling, including source and reflected acoustic signals, through convolution and rock physics models to determine subterranean properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If logging while drilling (LWD) equipment is used to estimate P-wave seismic impedance and density, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential acoustic signal processing functionality from complex LWD equipment and implements it using standard drill bit sound recording systems. By separating the acoustic signal acquisition (simple) from the complex inversion processing, the system achieves LWD-level accuracy without requiring sophisticated downhole equipment.
Solution Approach 2:
The patent replaces mechanical/LWD-based measurement systems with an acoustic signal processing system. Instead of using physical sensors downhole to directly measure seismic impedance, the system uses surface-recorded drill bit sounds and applies convolution algorithms to infer subsurface properties, substituting mechanical measurement with acoustic signal analysis.
2Measurement precision
If sophisticated LWD equipment is deployed, then density and seismic impedance values can be obtained, but cost increases
Solution Approach 1:
The patent uses inexpensive, readily available acoustic sensors and standard drilling equipment instead of expensive, specialized LWD tools. The system leverages the drill bit sound that is already being recorded for operational monitoring, adding value without requiring additional costly equipment deployment.
Solution Approach 2:
The patent creates a virtual copy of the subsurface geological properties through acoustic signal inversion. By processing the acoustic reflection signals mathematically, the system generates accurate models of density and seismic impedance without physically deploying expensive measurement tools into the borehole.
3Ease of manufacture
If drill bit sound is used for evaluation, then cost is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent employs iterative convolution algorithms that continuously refine the geological property models by comparing predicted acoustic signals with actual recorded signals. This feedback loop adjusts the density and seismic impedance estimates until the modeled acoustic response matches the recorded drill bit sound, ensuring high precision despite using simple equipment.
Solution Approach 2:
The patent transforms the acoustic signal from the time domain to the frequency domain through convolution and spectral analysis. By changing the parameter representation of the acoustic signal, the system extracts subtle geological information that would be invisible in the raw time-domain signal, maintaining measurement precision while using inexpensive equipment.
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
Enables real-time evaluation of geologic layer properties with reduced costs by leveraging drill bit sound, providing accurate density and seismic impedance values.
Implementation Method 1
the acoustic signal includes a source acoustic signal and a reflected acoustic signal, the reflected acoustic signal is produced in response to the source acoustic signal
Data Source
AI summary
Example computer-implemented methods, media, and systems for evaluating density and seismic impedance values of geologic layers using drill bit sound during drilling are disclosed. One example computer-implemented method includes receiving an acoustic signal associated with a sound produced by a well tool implemented to perform a well operation by contacting a portion of a subterranean zone, where the acoustic signal includes a source acoustic signal and a reflected acoustic signal, the reflected acoustic signal is produced in response to the source acoustic signal, and the sound is produced during a drilling operation. The acoustic signal is processed to determine the source acoustic signal and the reflected acoustic signal. A first signal is determined based on the source acoustic signal. A second signal is determined based on the reflected acoustic signal. Properties of the subterranean zone are determined based on a convolution of the first signal and the second signal.