Sonic Waveform Analysis for Drilling-Induced Rock Damage Mapping
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Solution Overview
Problem
Drilling-induced rock damage around wellbores poses challenges in predicting wellbore stability and hydrocarbon production, as existing methods lack effective means to accurately locate and characterize damage, leading to potential collapse, deformation, and reduced production.
Innovation Solution
A method utilizing sonic datasets to determine drilling-induced rock damage maps by processing sonic waveforms recorded at various source-receiver separations, generating logs and maps of sonic metrics such as slowness, which differentiate damaged from undamaged rock, allowing for informed completion strategies and risk mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional drilling methods are used without advanced characterization, then drilling operations can proceed quickly, but wellbore stability and rock damage cannot be accurately predicted
Solution Approach 1:
The patent replaces traditional mechanical rock damage assessment methods with acoustic/sonic wave-based detection. Sonic waves are transmitted through the rock formation and the resulting waveforms are analyzed to detect rock damage, substituting direct mechanical interaction with a non-contact acoustic field-based measurement system.
Solution Approach 2:
The patent transforms raw sonic waveform data into meaningful rock damage metrics by changing the parameter representation. It extracts features such as wave velocity, attenuation, and frequency content from the sonic signals, converting complex waveforms into interpretable parameters that characterize rock integrity and damage zones.
2Measurement precision
If sonic datasets are collected at multiple source-receiver separations for multiple source positions, then rock damage can be precisely characterized, but data acquisition time and processing complexity increase
Solution Approach 1:
The patent segments the rock formation into discrete zones based on rock damage characteristics by analyzing sonic waveforms from multiple source-receiver configurations. Each measurement configuration provides information about a specific spatial segment, and these segmented measurements are integrated to create a comprehensive rock damage map of the entire formation.
Solution Approach 2:
The patent uses multiple source positions and receiver separations (excessive action) to ensure complete coverage and accurate characterization of rock damage zones. By acquiring more data points than the absolute minimum required, it ensures that no damage zones are missed and provides redundancy for more robust interpretation.
3Reliability
If comprehensive sonic metrics are analyzed, then drilling-induced rock damage can be accurately mapped, but processing complexity and computational requirements increase
Solution Approach 1:
The patent extracts specific diagnostic features from the comprehensive sonic datasets, isolating the most informative parameters such as wave velocity changes, attenuation coefficients, and frequency spectrum characteristics. This extraction process separates the essential rock damage indicators from the redundant information in the raw sonic data.
Solution Approach 2:
The patent develops a multi-functional sonic analysis system that can evaluate multiple rock properties (integrity, damage zones, mechanical strength indicators) using the same sonic waveform data. The system serves multiple purposes: locating damage zones, characterizing their extent, and predicting wellbore stability, all from a single dataset analysis.
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 precise characterization of drilling-induced rock damage, enhancing wellbore stability, reducing sand production, and optimizing completion plans to extend well life and increase hydrocarbon production.
Implementation Method 1
A downhole sonic tool emits an acoustic wave into a rock formation
Data Source
AI summary
Methods and systems for determining a drilling-induced rock damage map are disclosed. The method includes obtaining a sonic dataset, including sonic waveforms recorded at a plurality of source-receiver separations for a plurality of source positions along an axis of a wellbore. The method further includes determining a log of a first metric using the sonic dataset and determining a map of a second metric using the sonic dataset. The method still further includes determining the drilling-induced rock damage map based, at least in part, on the log of the first metric and the map of the second metric.