Drill Bit Sound Analysis for Real-Time Rock Boundary Detection
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Solution Overview
Problem
Conventional methods for determining rock boundaries and acoustic velocities during wellbore drilling are inefficient, requiring drilling suspensions that increase costs and disrupt the drilling process, and struggle to separate direct and reflected drill bit sounds effectively.
Innovation Solution
A method that utilizes drill bit sound analysis by processing acoustic signals to separate direct and reflected signals, determining rock boundaries and velocities in real-time during drilling without interrupting the process, using a system with acoustic sensors and data processing to calculate two-way travel times and acoustic velocities from the drill bit to rock boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vertical seismic profiling (VSP) is used to determine rock boundaries and acoustic velocities, then measurement accuracy is improved, but drilling operation is interrupted for significant periods increasing cost and time
Solution Approach 1:
The drill bit serves dual purposes: both drilling the wellbore and generating acoustic signals for rock boundary detection. The drilling operation itself produces the acoustic energy needed for measurement, eliminating the need for separate measurement operations that would interrupt drilling.
Solution Approach 2:
The patent combines the drilling operation with the acoustic measurement operation into a single continuous process. The drill bit既是 drilling tool又是 acoustic source, and the drilling mud serves both as lubricant and as the medium for acoustic signal transmission and reception.
2Productivity
If drill bit sound is used as seismic source with surface geophones, then drilling suspension is avoided, but direct and reflected sounds cannot be effectively separated
Solution Approach 1:
Acoustic sensors positioned in the drill string act as intermediaries between the drill bit acoustic source and the rock boundaries. These sensors receive both direct and reflected sounds separately, enabling the system to distinguish and analyze reflected signals from rock boundaries without requiring surface geophones.
Solution Approach 2:
The patent moves the acoustic sensors from the surface dimension to the downhole dimension within the drill string. This spatial repositioning allows direct reception of acoustic signals close to the source, creating a new measurement dimension that enables separation of direct and reflected sounds through signal processing.
3Device complexity
If acoustic sensors are placed on ground surface, then equipment complexity is reduced, but signal attenuation in rock formations degrades measurement quality
Solution Approach 1:
The acoustic sensors are nested within the drill string structure, which itself is nested within the wellbore. This nested configuration places sensors in close proximity to the acoustic source (drill bit) and the target (rock boundaries), minimizing signal attenuation while maintaining relatively simple equipment architecture.
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 detection of rock boundaries and acoustic velocities, reducing drilling costs and allowing for continuous operation, with low-cost implementation and enhanced seismic data processing capabilities.
Implementation Method 1
receiving acoustic signals associated with sounds produced by a well tool implemented to perform a well operation
Implementation Method 2
The acoustic signals are composed of source acoustic signals and reflected acoustic signals produced in response to the source acoustic signals
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Implementations provide identification of rock boundaries and evaluation of rock interval velocities in subterranean zones. Actions can include receiving acoustic signals associated with sounds produced by a well tool implemented to perform a well operation by contacting a portion of a subterranean zone, the acoustic signals being composed of source acoustic signals and reflected acoustic signals produced in response to the source acoustic signals, processing the acoustic signals to determine the source acoustic signals and the reflected acoustic signals and determining properties of the subterranean zone based on the source acoustic signals and the reflected acoustic signals.