Real-Time Tool Mode Waveform Removal in Acoustic LWD
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current real-time slowness processing in acoustic logging-while-drilling (LWD) environments is hindered by drilling noise and tool mode waveforms, which suppress formation acoustic waveforms, making it difficult to identify formation properties effectively.
Innovation Solution
A real-time method for removing tool mode waveforms using a workflow that involves filtering, buffering, and threshold-based analysis of waveforms to distinguish and remove tool mode waveforms without relying on depth logs, allowing for the formation of a differential phase time semblance map to derive formation slowness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If acoustic LWD data acquisition is performed in real-time while drilling, then formation properties can be identified promptly, but tool mode waveforms and drilling noise suppress formation acoustic waveforms making identification difficult
Solution Approach 1:
The patent extracts and removes tool mode waveforms from the composite acoustic waveform signal using a waveform removal algorithm. This separates the harmful tool mode waveforms from the useful formation acoustic waveforms, allowing clear identification of formation properties in real-time without waiting for post-processing.
Solution Approach 2:
The patent introduces an intermediary processing system that includes a waveform buffer, filtering mechanism, and threshold-based detection. This intermediary system processes the raw acoustic signal in real-time, removing tool mode waveforms before formation analysis, thus enabling both real-time operation and accurate measurement.
2Productivity
If conventional real-time processing is used, then processing speed is maintained, but tool mode waveforms cannot be effectively removed without depth logs
Solution Approach 1:
The patent implements a self-service processing system where the waveform removal algorithm operates autonomously using only the acquired waveform data itself. The system buffers waveforms, applies filtering, and removes tool mode waveforms based on intrinsic waveform characteristics without requiring external depth log inputs, enabling reliable real-time processing.
Solution Approach 2:
The patent performs preliminary waveform buffering and filtering before formation analysis. By pre-processing the acoustic waveforms to remove tool mode waveforms in advance using a buffered approach with threshold-based detection, the system ensures that subsequent formation property identification operates on clean, de-noised data.
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 effective real-time identification of formation properties by suppressing tool mode waveforms, improving the accuracy of formation slowness determination during LWD operations.
Implementation Method 1
Acoustic logging relies on the analysis of seismic waves generated and recorded within a borehole
Implementation Method 2
Pressure pulses, which may also be referred to as acoustic waves, reflect off different parts of a formation or wellbore. The reflected pressure pulses may form secondary pressure pulses or secondary acoustic waves
Data Source
AI summary
Methods and systems for removing tool mode waveforms. The method may include disposing a bottom hole assembly (BHA) into a wellbore. The BHA may comprise at least one transmitter configured to transmit a pressure pulse and at least one receiver configured to record one or more waveforms. The method may further comprise performing a logging-while-drilling (LWD) operation in which the one or more waveforms are recorded with the at least one receiver, transmitting the one or more waveforms to an information handling system, removing one or more tool mode waveforms from the one or more waveforms to form an updated set of waveforms, and forming differential phase time semblance map based at least in part on the updated set of waveforms. The system may comprise the BHA and information handling system configured to remove one or more tool mode waveforms.