Acoustic Resonance Permeability Logging
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Solution Overview
Problem
Current methods for accurately measuring the permeability of geologic formations are inefficient, as they lack precise techniques for determining the ability of formations to transmit fluids, which is crucial for hydrocarbon exploration and recovery.
Innovation Solution
A method and apparatus using an acoustic wave source and receiver to generate and measure pressure at a resonant frequency within a borehole, allowing for the calculation of permeability by processing the amplitude of eigenwaves formed at the boundary between the borehole and the porous medium, along with a computer program product for determining permeability from these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional logging methods are used to measure permeability, then the measurement process is simple, but the measurement precision is insufficient
Solution Approach 1:
The patent applies acoustic wave vibration to induce radial oscillations in the borehole fluid and formation interface. By measuring the resonant frequency and damping characteristics of these oscillations, the system achieves precise permeability measurements. The acoustic source generates vibrations that propagate through the borehole fluid, and the receiver detects the resulting pressure variations, enabling accurate determination of formation permeability through vibration-based measurement.
Solution Approach 2:
The patent utilizes changes in acoustic wave parameters (frequency, amplitude, phase) as the acoustic wave interacts with the formation. By analyzing how these parameters change during propagation and reflection, the system extracts permeability information. The resonant frequency shift and damping ratio provide direct measurements of formation properties, transforming physical parameter changes into quantitative permeability data.
2Measurement precision
If accurate permeability measurements are obtained using resonance methods, then the measurement precision improves, but the ease of operation decreases
Solution Approach 1:
The system automatically identifies resonant frequencies and calculates permeability values without requiring manual intervention. The logging instrument self-adjusts the acoustic frequency to match formation resonances, automatically processes the pressure signal data, and computes permeability results. This automation maintains measurement precision while simplifying operator tasks to basic instrument deployment and data retrieval.
3Measurement precision
If resonance frequency measurements are used, then the measurement precision increases, but the loss of time increases due to frequency tuning and measurement cycles
Solution Approach 1:
The system employs periodic acoustic wave cycles at varying frequencies to sweep through the resonant range and identify formation resonances. By using repeated periodic measurements at different frequencies, the system efficiently locates the resonant peak and extracts permeability data. This periodic frequency sweeping approach balances measurement precision with time efficiency, completing accurate measurements in standardized time intervals.
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 provides accurate and efficient permeability measurements, enabling better resource allocation and hydrocarbon recovery by determining the fluid transmission ability of geologic formations.
Implementation Method 1
measuring a pressure, p(1), of an acoustic wave in the borehole
Implementation Method 2
the acoustic wave comprising a frequency that is about a resonant frequency of a system that includes the borehole and the porous medium
Implementation Method 3
an acoustic wave receiver for receiving an acoustic wave from the porous medium
Data Source
AI summary
A method for determining permeability of a porous medium of a formation, the method including: placing a logging instrument into a borehole that traverses the porous medium, the borehole filled with a borehole fluid; measuring a pressure, p(1), of an acoustic wave in the borehole at about a boundary between the porous medium and the borehole, the acoustic wave comprising a frequency that is about a resonant frequency of a system that includes the borehole and the porous medium; calculating the permeability from the pressure; and providing the permeability as output to a user.